www.icc-es.

org | (800) 423-6587 | (562) 699-0543 A Subsidiary of the International Code Council ®

ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE

STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS

AC434

Approved October 2011

PREFACE
Evaluation reports issued by ICC Evaluation Service, LLC (ICC-ES), are based upon performance features of
the International family of codes. (Some reports may also reference older code families such as the BOCA
National Codes, the Standard Codes, and the Uniform Codes.) Section 104.11 of the International Building Code®
reads as follows:

The provisions of this code are not intended to prevent the installation of any materials or to
prohibit any design or method of construction not specifically prescribed by this code,
provided that any such alternative has been approved. An alternative material, design or
method of construction shall be approved where the building official finds that the proposed
design is satisfactory and complies with the intent of the provisions of this code, and that the
material, method or work offered is, for the purpose intended, at least the equivalent of that
prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety.

This acceptance criteria has been issued to provide interested parties with guidelines for demonstrating
compliance with performance features of the codes referenced in the criteria. The criteria was developed through
a transparent process involving public hearings of the ICC-ES Evaluation Committee, and/or on-line postings
where public comment was solicited.

New acceptance criteria will only have an “approved” date, which is the date the document was approved by
the Evaluation Committee. When existing acceptance criteria are revised, the Evaluation Committee will decide
whether the revised document should carry only an “approved” date, or an “approved” date combined with a
“compliance” date. The compliance date is the date by which relevant evaluation reports must comply with the
requirements of the criteria. See the ICC-ES web site for more information on compliance dates.

If this criteria is a revised edition, a solid vertical line (│) in the margin within the criteria indicates a technical
change from the previous edition. A deletion indicator () is provided in the margin where wording has been
deleted if the deletion involved a technical change.

ICC-ES may consider alternate criteria for report approval, provided the report applicant submits data
demonstrating that the alternate criteria are at least equivalent to the criteria set forth in this document, and
otherwise demonstrate compliance with the performance features of the codes. ICC-ES retains the right to refuse
to issue or renew any evaluation report, if the applicable product, material, or method of construction is such that
either unusual care with its installation or use must be exercised for satisfactory performance, or if
malfunctioning is apt to cause injury or unreasonable damage.

NOTE: The Preface for ICC-ES acceptance criteria was revised in July 2011 to reflect changes in policy.

Acceptance criteria are developed for use solely by ICC-ES for purpose of issuing ICC-ES evaluation reports.

Copyright© 2011

@Seismicisolation
@Seismicisolation
 ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS MATRIX
(FRCM) COMPOSITE SYSTEMS (AC434)
1.0 INTRODUCTION Bond Strength or Tensile Strength of Concrete Repair and
1.1 Purpose: The purpose of this acceptance criteria Overlay Materials by Direct Tension (Pull-off Method),
ASTM International.
is to establish requirements for recognition of fiber-
reinforced cementitious matrix (FRCM) composite 1.3.12 ASTM D 1141-98 (2008), Standard Practice for
systems, used for the strengthening of masonry and Preparation of Substitute Ocean Water, ASTM
concrete structures, in ICC Evaluation Service, LLC (ICC- International.
ES), evaluation reports under the 2012 and 2009
® 1.3.13 ASTM D 2247-11, Standard Practice for
International Building Code (IBC). The basis of
Testing Water Resistance of Coatings in 100% Relative
recognition is IBC Section 104.11.
Humidity, ASTM International.
The reason for the development of this criteria is to
1.3.14 ASTM D 2344/D 2344M-00 (2006), Standard
provide guidelines for the evaluation of alternative
Test Method for Short-Beam Strength of Polymer Matrix
strengthening methods for masonry and concrete
Composite Materials and Their Laminates, ASTM
structural elements, where the codes do not provide
International.
requirements for testing and determination of structural
capacity, reliability and serviceability of these products. 1.3.15 ASTM D 3165-07, Standard Test Method for
Strength Properties of Adhesives in Shear by Tension
1.2 Scope: This criteria applies to passive fiber-
Loading of Single Lap-Joint Laminated Assemblies, ASTM
reinforced cementitious matrix (FRCM) composite systems
International.
used to strengthen existing masonry and concrete
structures. Properties evaluated include FRCM material 1.3.16 ASTM E 4-10, Standard Practices for Force
properties; axial, flexural and shear capacities of the Verification of Testing Machines, ASTM International.
FRCM system; performance of the FRCM system under 1.3.17 ASTM E 83-10a, Standard Practice for
environmental exposures; performance under exposure to Verification and Classification of Extensometers, ASTM
fire conditions; and structural design procedures. International.
1.3 Referenced Codes and Standards: 1.3.18 ASTM E 104-02 (2007), Standard Practice for
®
1.3.1 2012 and 2009 International Building Code Maintaining Constant Relative Humidity by Means of
(IBC), International Code Council. Aqueous Solutions, ASTM International.
1.3.2 ACI 318-11 (2012 IBC), Building Code 1.4 Definitions:
Requirements for Structural Concrete and Commentary, 1.4.1 Design Values: The FRCM composite
American Concrete Institute. system’s load and deformation design capacities that are
1.3.3 ACI 318-08 (2009 IBC), Building Code based on load and resistance factor design (strength
Requirements for Structural Concrete and Commentary, design) method.
American Concrete Institute. 1.4.2 FRCM Composite Material: A fiber-reinforced
1.3.4 ASCE 41-06: Seismic Rehabilitation of Existing cementitious matrix (FRCM) is a composite material
Buildings, American Society of Civil Engineers. consisting of a sequence of one or more layers of cement-
based matrix reinforced with fibers in the form of open grid
1.3.5 TMS 402-11/ACI 530-11/ASCE 5-11 (2012
(mesh). When adhered to concrete or masonry structural
IBC), Building Code Requirements for Masonry Structures,
members, they form an FRCM system. Components are:
American Concrete Institute.
1.4.2.1 Structural Reinforcement Grid: Open
1.3.6 TMS 402-08/ACI 530-08/ASCE 5-08 (2009
grid (mesh) of strands made of fibers [i.e., aramid, alkali
IBC), Building Code Requirements for Masonry Structures,
resistant (AR) glass, carbon, and polyparaphenylene
American Concrete Institute.
benzobisoxazole (PBO)], consisting of primary direction
1.3.7 ASTM C 138-10b, Standard Test Method for (PD) and secondary direction (SD) strands connected
Density (Unit Weight), Yield, and Air (Gravimetric) of perpendicularly. The typical strand spacing of PD and SD
Concrete, ASTM International. strands is less than one inch (25.4 mm).
1.3.8 ASTM C 157-08, Standard Test Method for 1.4.2.2 Cement-based Matrix: A polymer-
Length Change of Hardened Hydraulic Mortar and modified cement-based binder (mortar) that holds in place
Concrete. the structural reinforcement grids in FRCM composite
material.
1.3.9 ASTM C 387/C 387M-11, Standard
Specification for Packaged, Dry, Combined Materials for 1.4.3 Cracking Load and Displacement: Load and
Mortar and Concrete, ASTM International. displacement at which the moment-curvature relationship
of the masonry or concrete member first changes slope or
1.3.10 ASTM C 947-03 (2009), Standard Test Method
at which the cracking moment as defined in ACI 318,
for Flexural Properties of Thin-Section Glass-Fiber-
Section 9.5.2.3, or TMS 402, Section 3.3.5.5, is reached,
Reinforced Concrete (Using Simple Beam with Third-Point
whichever occurs first.
Loading), ASTM International.
e1 1.4.4 Yielding Load and Displacement: Load and
1.3.11 ASTM C 1583/C 1583M-04 , Standard Test
displacement at which longitudinal steel reinforcement of
Method for Tensile Strength of Concrete Surfaces and the
@Seismicisolation
@Seismicisolation
2
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

the reinforced masonry or concrete member reaches its described in this section, and any additional tests
yield strength as defined in ACI 318, Section 2.2. identified by the applicant for special features of the
1.4.5 Passive Composite Systems: Composite product or system, shall be specified.
systems that are not post-tensioned after installation are Overall, qualification testing shall provide data on
considered as passive composite systems. material properties, force and deformation limit states,
1.4.6 Rational Analysis and Design Procedure: A including failure modes of the composite material and
each structural system described in Sections 4.0 and 5.0,
method of structural analysis and design that takes into
to support a rational analysis and design procedure. The
account equilibrium, structural stability, geometric
specimens shall be constructed under conditions specified
compatibility, and both short- and long-term material
by the evaluation report applicant to be recognized in the
properties.
ICC-ES evaluation report, including curing. The specimens
1.4.7 FRCM Composite Material Configuration: A shall be prepared to verify the range of the FRCM
combination of all applicable parameters that affect the composite material configurations (layers, thickness,
performance of the FRCM composite material, such as components, bonding agents, etc.) specified by the
layers, thicknesses, components, bonding agents, etc. applicant. Tests shall simulate the anticipated range of
2.0 BASIC INFORMATION loading conditions, load levels, deflections, and ductility.

2.1 General: The following information shall be 4.0 MATERIAL TEST METHODS
submitted: 4.1 General: Required FRCM composite material
2.1.1 Product Description: A detailed description of physical, mechanical, and durability properties are
the FRCM system is needed, including the following items: described in this section along with the test procedures.
Properties obtained from these tests shall be considered
1. Description and identification of the product or in the design criteria and limitations described in Section
system. 8.0. Evaluation of test results shall be made on the basis
2. Restrictions or limitations on use. of the average values obtained from a minimum of five
specimens for each condition. Table 1 offers a summary of
2.1.2 Installation Instructions: Instructions shall the minimum material tests required for each FRCM
include the following items. material system.
1. Description of how the product or system will 4.2 Physical and Mechanical Properties of FRCM
be used or installed in the field. Composite Material:
2. Procedures establishing quality control in field 4.2.1 Drying Shrinkage: A panel of FRCM material
installations. for this test shall be cured, tested, and measured in
3. Requirements for product handling and accordance with general procedures outlined in ASTM C
storage. 157. Coupon specimens shall be cut from larger size
panels. Five coupon specimens shall be used for drying
4. For installations that depend on bond between shrinkage measurements for each FRCM configuration.
the system and the substrate, on-site testing of bond to The size of specimens shall be 3 by 16 inches (76 by 400
the substrate is required. mm). Caution shall be used to eliminate bending error that
2.1.3 Packaging and Identification: A description may occur.
of the method of packaging and field identification of the 4.2.2 Void Content: Five FRCM specimens shall be
system components. Identification provisions shall include tested for each FRCM configuration. The size of
the evaluation report number and the name or logo of the specimens shall be 3 by 6 inches (75 by 152 mm). The
inspection agency. tests shall be conducted in accordance with ASTM C 138.
2.1.4 Field Preparation: A description of the Air content and unit weight shall be measured.
methods of field-preparation, such as proportioning and 4.2.3 Tensile Strength: Tensile testing to determine
mixing, application, curing, and finishing. the tensile strength, elongation, and modulus of elasticity
2.2 Testing Laboratories: Testing laboratories shall shall be conducted on coupons cut from FRCM panels laid
comply with the ICC-ES Acceptance Criteria for Test up using a procedure similar to that in the actual in-service
Reports (AC85) and Section 4.2 of the ICC-ES Rules of application and according to the applicant’s instructions.
Procedure for Evaluation Reports. The test procedures shall comply with the “Tensile Testing
of Fiber-Reinforced Cementitious Matrix (FRCM)
2.3 Test Reports: Test reports shall comply with
Composite Specimens” included in Annex A. Tests shall
AC85.
be conducted for both primary and secondary grid
2.4 Product Sampling: Products shall be sampled in directions, if different and required in the structural
accordance with Section 3.1 of AC85. application. A minimum of five specimens are required for
3.0 TEST AND PERFORMANCE REQUIREMENTS each FRCM configuration.
4.2.4 Composite Interlaminar Shear Strength:
3.1 Qualification Test Plan: A qualification test plan
Composite interlaminar shear strength tests on FRCM
shall be submitted for ICC-ES staff review prior to any
panels shall follow general procedures of ASTM D 2344.
testing. The intent of testing is to verify the design
Alternatively, test procedures of ASTM C 947 can be
equations and assumptions used in the engineering
adopted for FRCM in conjunction with provisions of ASTM
analysis and presented in the Design Criteria Report
D 2344 for interpretation of results and reporting regarding
referenced in Section 8.0. All or part of the tests
@Seismicisolation
@Seismicisolation
3
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

interlaminar related issues. A minimum of five specimens 4.7 Lap Tensile Strength: When applying FRCM
are required for each FRCM configuration. composite materials for strengthening of structural
4.3 Properties of Mortar Matrix: Mortar used in masonry or concrete members, splices and laps will be
necessary for the grid reinforcement. To determine the
FRCM composite material as matrix shall comply with
relative tensile strength at the grid overlap area, lap tensile
ASTM C 387/C 387M, which covers the production,
strength testing is required. This test will be particularly
properties, packaging, and testing of packaged, dry,
useful if the joint configuration closely simulates the actual
combined materials for mortars. Normal-strength mortar
joint in material field application.
shall have minimum compressive strengths of 2,500 and
3,500 psi (17.0 and 24.0 MPa) at seven and 28 days, It is understood that in application of multilayer FRCM
respectively. A minimum of five specimens are required for composite materials, the laps shall be staggered from the
each mortar type to be recognized in the ICC-ES laps in the nearby layer. Laps in one layer shall start with a
evaluation report. minimum distance equivalent to the development length of
4.4 Freezing and Thawing: fiber strands in the matrix established by the applicant, or
larger.
4.4.1 Procedure: Freezing and thawing conditioning
is introduced for both tension FRCM panel specimens 4.7.1 Procedure: The general test procedures of
(Section 4.2.3) and interlaminar shear FRCM specimens ASTM D 3165 shall be used with exposures listed in Table
(Section 4.2.4). For each specimen type, five specimens 2. Fifty test coupons shall be cut from a larger FRCM
shall be conditioned and five shall be kept at ambient material panel. The panel shall consist of only one layer of
temperature as benchmarks. A total of twenty specimens FRCM material. The grid in the panel shall be two-piece
is required. The size of specimens shall be the same as with an overlap length in the middle. The lap length may
that required for tensile testing (described in Section vary, but a minimum 2-inch (51 mm) lap length is
4.2.3). Ten samples shall be conditioned for one week in a recommended. The coupons shall be cut having the same
humidity chamber [100% humidity, 100°F (37.7°C)]. These dimensions as described in the tensile strength testing
specimens shall then be subjected to twenty freeze-thaw process in Annex A, such that the overlap length is
cycles. Each cycle consists of a minimum of four hours at positioned at mid-length. Curing, specimen preparation,
0°F (-18°C), followed by 12 hours in a humidity chamber tab preparation and properties, tab installation and grip
[100 percent humidity, 100°F (37.7°C)]. conditions shall follow those described in the tensile
strength testing in Annex A. Multiple-layer tests can also
4.4.2 Conditions of Acceptance: At the end of be considered with a configuration that serves the purpose
freeze/thaw cycles, the specimens shall be visually of this test.
examined for surface changes such as erosion, scaling,
cracking, and crazing. The samples shall then be tested 4.7.2 Conditions of Acceptance: For unconditioned
for tensile strength and interlaminar shear. Specimens are specimens (control), lap tensile strength shall be not less
tested in their primary direction. Freeze/thaw specimens than that of a specimen with continuous reinforcement.
shall retain at least 85 percent of the tensile and shear The exposed specimens shall retain the percentage of
properties of control specimens. tensile strength generated on control specimens noted in
Table 2.
4.5 Aging: These tests shall be considered in design
criteria and limitations. 4.8 Bond Strength:
4.5.1 Procedure: Both wet and dry FRCM panel 4.8.1 Procedure: For tensile bond testing, forty
specimens are aged in accordance with Table 2. Both FRCM materials shall be prepared. The FRCM material
exposed and control specimens are then tested for tensile shall be applied onto the substrate [minimum 2.5 inches
strength, tensile modulus, elongation, and interlaminar (63 mm) thick] in accordance with the applicant’s
shear strength in accordance with Sections 4.2.3 and instructions. Thirty specimens shall then be exposed to
4.2.4. Specimens shall be tested in their primary direction. conditions presented in Table 2. Ten specimens shall be
A minimum of five specimens for each FRCM kept in standard laboratory conditions as control
configuration are required. specimens. The test shall follow the general procedures of
the ASTM C 1583. The pull-off strength shall be computed
4.5.2 Conditions of Acceptance: Control and
based on the maximum indicated load. A minimum of five
exposed specimens shall be visually examined using 5x
specimens for each FRCM configuration are required.
magnification. Surface changes affecting performance,
such as erosion, cracking, and crazing, are unacceptable. 4.8.2 Conditions of Acceptance: The predominant
The exposed specimens shall retain the percentage of mode of failure shall be cohesive failure at a strength of at
tensile and interlaminar shear properties generated on least 200 psi (1.38 MPa) for the control specimen. The
control specimens noted in Table 2. exposed specimens shall retain the percentage of bond
4.6 Fuel Resistance: Ten FRCM panel specimens strength generated on control specimens noted in Table 2.
shall be prepared of which five are exposed to diesel fuel 4.9 Fire-resistance-rated Construction: The effect
reagent for a minimum of four hours. After conditioning, of the FRCM material system on fire-resistance rated
the specimens shall be tested in accordance with Section construction shall be evaluated according to Section 703
4.2.3 for tensile strength, tensile modulus and elongation. of the IBC.
Specimens shall be tested in their primary direction.
Specimens shall retain at least 85 percent of the tensile 4.10 Interior Finish: The classification of the FRCM
properties of control specimens. A minimum of five composite system as an interior finish shall be determined
specimens are required for each FRCM configuration. according to Section 803 of the IBC.
@Seismicisolation
@Seismicisolation
4
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

5.0 STRUCTURAL PERFORMANCE TEST METHODS Figure 1. For gravity (non-dynamic) loading application,
the load may be monotonically applied. The limit states
5.1 General: Tests required to validate the
shall be determined based on material properties and
performance of structural components are described in
maximum concrete compression strain of 0.003.
this section, along with the recommended procedures.
Evaluation of test results shall be made on the basis of the 5.3.1.2 Shear Tests:
values obtained from a minimum of three identical
5.3.1.2.1 Configuration: Beam spans shall be
specimens. The deviation of any strength value obtained
configured to induce shear limit states or failure modes as
from any single test shall not vary from the average value
related to FRCM performance. Either simple or rigid
for all tests by more than 15 percent. If such deviation
supports are permitted. Extremes of dimensional, FRCM
from the average value for any test exceeds 15 percent,
reinforcing, and compressive strength parameters of the
then additional tests shall be performed until the deviation
concrete beams to be strengthened by FRCM shall be
of any test does not exceed 15 percent or a minimum of
considered.
six tests have been performed.
5.3.1.2.2 Procedure: For seismic or wind
5.2 Masonry:
loading, the lateral load procedure shall conform to Figure
5.2.1 Wall Flexural Tests (Out-of-plane Load): 1. For gravity loading, the load may be monotonically
applied. The limit states shall be determined based on
5.2.1.1 Configuration: Wall flexural specimens
geometric and material properties.
shall be configured to induce out-of-plane flexural limit
states and failure modes as related to FRCM 5.3.2 Beam-to-column Joints:
performance. Extremes of dimensional, FRCM reinforcing,
5.3.2.1 Configuration: The beam-to-column joint
and masonry compressive strength parameters of the
shall be configured to induce joint-related limit states or
masonry wall to be strengthened by the FRCM shall be
failure modes as related to FRCM performance. The
considered.
column portion may be constructed to represent a section
5.2.1.2 Procedure: For seismic or wind-load between inflection points. Extremes of dimensional, FRCM
application, the lateral load procedure shall conform to reinforcing and compressive strength parameters of the
Figure 1. For gravity (non-dynamic) loading application, concrete beam-to-column joins to be strengthened by
the load may be monotonically applied until the FRCM shall be considered.
strengthening system is damaged, its capacity is reached,
5.3.2.2 Procedure: The lateral load procedure
or desired limit states are achieved. Specimens may be
shall conform to Figure 1. A vertical load shall be
axially loaded to consider effects of axial loads. The
continuously applied and varied within a specified range.
loading in the out-of-plane direction may be applied at
The limit states shall be determined based on geometric
third-points, by airbags or by other means representing
and material properties.
actual conditions.
5.3.3 Columns:
5.2.2 Wall Shear Tests (In-plane Shear):
5.3.3.1 Pure Axial Tests:
5.2.2.1 Configuration: Wall shear specimens
shall be configured to induce in-plane shear limit states or 5.3.3.1.1 Configuration: Column specimens
failure modes as related to FRCM performance. Extremes shall be configured to induce axial compression limit
of dimensional, FRCM reinforcing and masonry states or failure modes as related to FRCM performance.
compressive strength parameters of the masonry wall to Extremes of dimensional, FRCM reinforcing, and strength
be strengthened by the FRCM shall be considered. parameters of the concrete columns to be strengthened by
FRCM shall be considered.
5.2.2.2 Procedure: For seismic or wind-load
application, the load procedure shall conform to Figure 1. 5.3.3.1.2 Procedure: The load shall be
For non-dynamic loading application, the lateral load may monotonically applied. The limit states shall be determined
be monotonically applied until the strengthening system is based on geometric, material properties and column end
damaged, its capacity is reached, or desired limit states support conditions.
are achieved. Specimens also may be axially loaded to
consider effects of axial loads. 5.3.3.2 Flexural Tests:

5.3 Concrete: 5.3.3.2.1 Configuration: Column specimens

shall be configured to induce flexural limit states or failure
5.3.1 Beams: modes as related to FRCM performance. Either cantilever
or double fixity (reverse curvature) is permitted in
5.3.1.1 Flexural Tests:
specimens. Extremes of dimensional, FRCM reinforcing,
5.3.1.1.1 Configuration: Beam spans shall be and strength parameters of the concrete columns to be
configured to induce flexural limit states or failure modes strengthened by FRCM shall be considered.
as related to FRCM performance. Either simple or rigid
5.3.3.2.2 Procedure: For seismic or wind-load
supports are permitted. Extremes of dimensional, FRCM
applications, the lateral load procedure shall conform to
reinforcing, and compressive strength parameters of the
Figure 1. For gravity (non-dynamic) loading applications,
concrete beams to be strengthened by FRCM shall be
the load may be monotonically applied. Axial loads within
considered.
a specific range shall be applied. The limit states shall be
5.3.1.1.2 Procedure: For seismic or wind-load determined based on geometric, material properties and
application, the lateral load procedure shall conform to column end support conditions.
@Seismicisolation
@Seismicisolation
5
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

5.3.3.3 Shear Tests: 1. Information noted in the referenced standard.

5.3.3.3.1 Configuration: Column specimen 2. Description of test setup.
spans shall be configured to induce shear limit states or 3. Rate and method of loading.
failure modes as related to FRCM performance. Double
fixity (reverse curvature) is required. Extremes of 4. Deformation and strain measurements.
dimensional, FRCM reinforcing, and compressive strength 5. Modes of failure.
parameters of the concrete columns to be strengthened by
FRCM shall be considered. 7.3 Design Criteria Report: The report shall include a
complete analysis and interpretation of the qualification
5.3.3.3.2 Procedure: For seismic or wind-load test results. Design stress and strain criteria for masonry
application, the lateral load procedure shall conform to or concrete members shall be specified based on the
Figure 1. For gravity (non-dynamic) loading application, analysis, but shall not be higher than specified in Section
the load may be monotonically applied. Axial loads within 8.0.
a specific range shall be applied. The limit states shall be
determined based on geometric, material properties and Design stresses and strains shall be based on a
column end support conditions. characteristic value approach verified by test data. The
drying shrinkage values determined in Section 4.0 shall be
5.3.4 Slabs: considered in the design procedure. The design shall
5.3.4.1 Configuration: Slab spans shall be consider, if applicable, secondary stresses resulting when
configured to include flexural limit states or failure modes dead loads are relieved during application and
as related to FRCM performance. Either simple or rigid subsequently reapplied. Adoption of the minimum
supports are permitted. Extremes of dimensional, FRCM acceptable standards for design outlined in Section 8.0
reinforcing and compressive strength of the concrete slabs does not eliminate the need for structural testing.
to be strengthened by FRCM shall be considered. Situations not covered in Section 8.0 shall be subject to
special considerations and testing, and design values shall
5.3.4.2 Procedure: For gravity (non-dynamic) be compatible with the conservative approach adopted in
loading application, the load may be monotonically Section 8.0.
applied. The limit states shall be determined based on
8.0 MINIMUM ACCEPTABLE DESIGN CRITERIA
material properties and maximum concrete compression
strain of 0.003. 8.1 General: Design procedures shall be in
accordance with Chapter 19 or 21 of the IBC, as
6.0 QUALITY CONTROL
applicable, except as modified in this section. FRCM
6.1 Manufacturing: Quality control procedures during material properties to be used for design as described in
manufacture of the system components as described in this section are obtained from Section 4.0. The value of
Section 1.4.2 shall be described a quality documentation any material property to be used in the design equations
complying with the ICC-ES Acceptance Criteria for Quality of this section is defined as the average value minus three
Documentation (AC10), and there shall be inspections by times the standard deviation. The limit state design
an inspection agency accredited by the International capacities as determined in accordance with Section 8.0
Accreditation Service, Inc. (IAS), or otherwise acceptable of this criteria cannot exceed the five percent fractile
to ICC-ES. A qualifying inspection shall be conducted at values of the capacities obtained experimentally in
each manufacturing facility when required by the ICC-ES accordance with Section 5.0.
Acceptance Criteria for Inspections and Inspection 8.2 Masonry:
Agencies (AC304).
8.2.1 Flexural Strength Enhancement: The FRCM
6.2 Installation and Special Inspection: All composite material bonded to surfaces of masonry may be
installations shall be done by applicators approved by the used to enhance the design flexural strength out of the
report applicant. The quality assurance program shall be plane of the wall by acting as additional tension
documented. Special inspection is required and shall reinforcement. In such cases, the section analysis shall be
comply with Section 1704 of the IBC. Duties of the special based on normal assumptions of strain compatibility
inspector shall be prepared by the report applicant, and between masonry, steel reinforcement (if any), and FRCM
included in the evaluation report. The maximum debonded composite material. The out-of-plane flexural strength of a
area permitted after installation of bonded FRCM systems (reinforced or unreinforced) masonry wall depends on the
shall be specified by the applicant. controlling failure mode. Failure modes for an FRCM-
7.0 FINAL SUBMITTAL strengthened wall include:

7.1 Contents: The final submittal shall consist of a  Crushing of the masonry in compression
test report or test reports, and a design criteria report, as  Debonding of the FRCM from the masonry
described in this section. The final submittal shall include substrate (FRCM debonding)
the qualification plan described in Section 3.0 of this
acceptance criteria. Contents of the final submittal are  Tensile yielding of the steel reinforcement
described in the Sections 7.2 and 7.3.  Tensile rupture of FRCM material
7.2 Test Report: The testing laboratory shall report on The effective tensile strain level in the FRCM composite
the qualification testing performed according to the material attained at failure, εfe, shall be limited to the
approved test plan. Besides the information requested in design tensile strain of the FRCM composite material, εfd,
Section 2.4, the test report shall include the following: defined in Equation (1):
@Seismicisolation
@Seismicisolation
6
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)
.
εfd = 0.7 εfu ≤ 0.012 (1) ffv =0.75 Ef.εfv (5)

where εfu is the ultimate tensile strain of the FRCM FRCM shall be applied on both sides of the wall with
composite material. The effective tensile stress level in the primary fiber strands oriented perpendicular to the applied
FRCM reinforcement attained at failure, ffe, shall be shear force. Fiber strands shall not have a misalignment of
calculated in accordance with Equation (2): more than 5 degrees.
. The design shear strength shall be calculated in
ffe = 0.85 Ef.εfe with εfe ≤ εfd (2)
accordance with Equation (6).
where Ef is the tensile modulus of elasticity of the cracked
ᶲv Vn = ᶲv (Vm+Vf) (6)
FRCM composite material. Fiber strands shall be oriented
perpendicular to the direction of the applied bending where Vn is the nominal shear strength; Vm and Vf are the
moment and shall not have a misalignment of more than 5 contribution of the (unreinforced or reinforced) masonry
degrees. and the FRCM composite material to the nominal shear
The design flexural strength shall be calculated in strength, respectively. Vm is calculated in accordance with
accordance with Equation (3). TMS 402. Vf is calculated as defined in Equation (7):

ᶲm Mn = ᶲm (Mm+Mf) (3) Vf = 2 n Af L ffv (7)

where Mn is the nominal flexural strength; Mm and Mf are where Af is the area of the grid reinforcement by unit width
the contribution of the reinforced masonry and the FRCM effective in shear, n is the number of layers of grid
composite material to the nominal flexural strength, reinforcement, and L is the length of the wall in the
respectively. In the case of unreinforced masonry, only the direction of the applied shear force. The strength reduction
term Mf is considered. The strength reduction factor for factor for shear, ᶲv, is equal to 0.75. A minimum
flexure, ᶲm, is equal to 0.6 for both reinforced and development length of 6 inches (152 mm) shall be
unreinforced masonry. considered.
8.2.2.1 Limitations: To limit the total force per unit
For the computation of Mn, when the FRCM composite
material is applied on both sides of the wall, the width transferred to the masonry, the increment in shear
contribution of FRCM in the compression side is strength provided by the FRCM reinforcement shall not
neglected. exceed 50 percent of the capacity of the structure without
strengthening for both unreinforced and conventionally
FRCM application does not contribute to the enhancement reinforced masonry walls. Strengthening is limited to
of the nominal out-of-plane shear strength of the masonry maximum wall thickness of 12 inches (305 mm).
wall which shall be calculated according to TMS 402. A
8.3 Concrete:
minimum development length of 6 inches (152 mm) shall
be considered. 8.3.1 Flexural Strength Enhancement of
8.2.1.1 Limitations: In the case of unreinforced Reinforced Concrete Members: The FRCM composite
masonry, when subjected to out-of-plane loading, the wall material bonded to surfaces of reinforced concrete
behaves as a simply supported element or very nearly so, members may be used to enhance the design flexural
and the influence of wall arching mechanisms can be strength of sections by acting as external tension
neglected. An arching mechanism can potentially develop reinforcement. In such cases, section analysis shall be
in a wall with a height-to-thickness (H/t) ratio of less than 8 based on the following normal assumptions: (a) plane
when the wall is built between stiff supports. The influence sections remain plane after loading; (b) the bond between
of arching in the out-of-plane behavior decreases for walls the FRCM and the substrate remains effective; (c) the
with H/t ratios greater than 14. As a reference, Tables 7-5 maximum usable compressive strain in the concrete is
and 7-10 of ASCE 41 provide H/t ratios where an 0.003; (d) FRCM has a linear elastic behavior to failure.
unreinforced masonry wall does not need to be analyzed The flexural strength of a reinforced concrete section
for out-of-plane seismic forces and, therefore, does not depends on the controlling failure mode. Failure modes for
require strengthening. For conventionally reinforced an FRCM-strengthened section include:
masonry walls, to limit the total force per unit width
 Crushing of the concrete in compression before
transferred to the masonry, the increment in flexural
yielding of the reinforcing steel.
strength provided by the FRCM reinforcement shall not
exceed 50 percent of the capacity of the structure without  Yielding of the steel in tension followed by
strengthening. concrete crushing.
8.2.2 Shear Strength Enhancement: The FRCM  Shear/tension delamination of the concrete cover
composite material bonded to surfaces of masonry may be (cover delamination).
used to enhance the design shear strength in the plane of
the wall by acting as shear reinforcement.  Debonding of the FRCM from the concrete
substrate (FRCM debonding).
The design tensile strain in the FRCM shear
reinforcement, εfv, shall be calculated by Equation (4):  Tensile rupture of FRCM material.

εfv = 0.4 εfu ≤ 0.004 (4) The effective tensile strain level in the FRCM
reinforcement attained at failure, εfe, shall be limited to the
The design tensile strength in the FRCM shear design tensile strain of the FRCM composite material, εfd,
reinforcement, ffv, shall be calculated in accordance with defined in Equation (8):
Equation (5):
@Seismicisolation
@Seismicisolation
7
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

εfd = 0.7 εfu ≤ 0.012 (8) f cc  f c

E2  (15)
The effective tensile stress level in the FRCM  ccu
reinforcement attained at failure, ffe, in the FRCM
reinforcement shall be calculated in accordance with where Ec is the modulus of elasticity of concrete, E2 is the
Equation (9): slope of linear portion of stress-strain model for FRCM-
ffe =0.85 Ef εfe where εfe ≤ εfd (9) confined concrete, fc is the compressive stress in concrete,
f′c is the specified compressive strength of concrete, f′cc is
Fiber strands shall be oriented parallel to the major axes the maximum compressive strength of confined concrete,
of the member and shall not have a misalignment of more c is the compressive strain level in the concrete, ccu is the
than 5 degrees. ultimate compressive strain of confined concrete, and 't is
The design flexural strength shall be calculated in the transition strain in the stress-strain curve of FRCM-
accordance with Equation (10). confined concrete. ccu corresponds to 0.85f′cc in a lightly
confined member (member confined to restore its concrete
ᶲm Mn = ᶲm (Ms+Mf) (10) design compressive strength), or to the ultimate axial
where Mn is the nominal flexural strength, Ms and Mf are compressive strain of confined concrete corresponding to
the contribution of the steel reinforcement and the FRCM failure in a heavily confined member.
composite material to the nominal flexural strength, The maximum confined concrete compressive
respectively. The strength reduction factor ᶲm is given by strength, f′cc, and the maximum confinement pressure, fl,
Equation (11), as defined in ACI 318: shall be calculated using Equations (16), (17a) and (17b):
f′cc = f′c + Ψf 3.3 κa fl (16)
{ (11) fl = (2nAfEfεfe)/D for circular cross section (17a)
2 2 1/2
fl = (2nAfEfεfe)/(b +h ) for rectangular cross section(17b)
where εt is the net tensile strain in extreme tension steel
where Af is the area of grid reinforcement by unit width, n
reinforcement at nominal strength, and εsy is the steel
is the number of layers of grid reinforcement, D is the
tensile yield strain.
diameter of the compression member with circular cross
8.3.1.1 Limitations: To limit the total force per unit section, and b and h are the short and the long side
width transferred to the concrete, the increment in flexural dimensions of the compression member with rectangular
strength provided by the FRCM reinforcement shall not cross section, respectively. The additional strength
exceed 50 percent of the capacity of the structure without reduction factor, Ψf, shall be taken equal to 0.95. The
strengthening. efficiency factor, κa, shall be calculated using Equation
8.3.1.2 Serviceability: The tensile stress in the (20). The effective compressive strain level in the FRCM,
steel reinforcement under service load, fss, shall be limited fe, shall be given by:
to 80 percent of the steel yield strength, fy, as indicated in fe = 0.55 fu (18)
Equation (12).
The minimum confinement ratio fl /f′c shall not be less than
fss ≤ 0.80 fy (12) 0.08.
8.3.1.3 Creep-rupture and Fatigue Stress The contribution of the mortar to the compressive strength
Limits: The tensile stress levels in the FRCM of the FRCM-confined compression member shall be
reinforcement under service load, ffs, shall be limited to the neglected.
values shown in Table 3.
The ultimate axial compressive strain of confined
8.3.2 Axial Load Capacity Enhancement: The
concrete, ccu, shall not exceed 0.01 to prevent excessive
FRCM composite material may be applied to external
surfaces of rectangular and circular reinforced concrete cracking and the resulting loss of concrete integrity. ccu
compression members to enhance the axial load capacity. shall be calculated using the following stress-strain
relationship:
The stress-strain for FRCM-confined concrete is illustrated
in Figure 2 and shall be determined using the following  fl   fe 
0.45

expressions:  ccu   c 1.5  12 b     0.01 (19)
 f c   c  
 
  Ec  E2   2
2

 Ec c 
fc  
 c 0   c   t (13)
4 f c where 'c is the compressive strain of unconfined concrete
 corresponding to f′c. The efficiency factor, κb, shall be
 f c  E2 c  t   c   ccu
calculated using Equation (21).

2 f c Based on the limitation set by Equation (19), f′cc shall not

 t  (14) exceed the value of the stress corresponding to ccu equal
Ec  E2 to 0.01.

@Seismicisolation
@Seismicisolation
8
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

8.3.2.1 Circular Sections: For circular cross- The bond-reduction coefficient, κv, shall be taken as 0.4.
sections, the shape factors κa and κb in Equations (16) and
(19), respectively, shall be taken as 1.0. The design tensile strength of the FRCM shear
reinforcement, ffv, shall be calculated in accordance with
8.3.2.2 Rectangular Sections: Rectangular Equation (24):
sections where the ratio of longer to shorter section side .
dimension is not greater than 2.0, may have axial ffv = 0.85 Ef. εfv (24)
compression capacity enhanced by the confining effect of Fiber strands shall be oriented perpendicular to the axis of
FRCM material placed with fiber strands running the member and shall not have a misalignment of more
essentially perpendicular to the members’ axis. For than 5 degrees.
rectangular cross-sections, the shape factors κa in
Equation (16) and κb in Equation (19) shall be calculated The design shear strength shall be calculated in
using Equations (20) and (21), respectively (Figure 3). accordance with Equation (25).
2 ᶲv Vn = ᶲv (Vc + Vs + Vf) (25)
A b
a  e   (20) where Vn is the nominal shear strength; Vc, Vs, and Vf are
Ac  h  the contribution of the concrete, the steel reinforcement
and the FRCM composite material to the nominal shear
A h
0.5
strength, respectively. The strength reduction factor ᶲv
b  e   (21) shall be equal to 0.75 as per ACI 318. Vc and Vs are
Ac  b  calculated according to ACI 318. The shear contribution of
the FRCM shear reinforcement, Vf, shall be given by
where, Equation (26)



Ae 1   b h  h  2r    h b  b  2r 
2 2
 3A   
g g
Vf = n Af ffv d (26)

Ac 1  g where n is the number of layers of grid reinforcement, Af is

(22) area of grid reinforcement by unit width effective in shear,
and d is the distance from extreme compression fiber to
In Equation (22), Ac is the net cross-sectional area of the
centroid of tension reinforcement. The total shear strength
compression member, Ae is the area of the effectively
provided by FRCM and steel reinforcement shall be limited
confined concrete, Ag is the gross cross-sectional area of
to the following:
the compression member, ρg is the ratio of the area of
longitudinal steel reinforcement, As, to the gross cross-
sectional area of the compression member. Vs  V f  8 f c 'bwd
(27)
The cross-section corners must be rounded to a radius, r,
3
not less than /4 inch (20 mm), before placing FRCM Vs  V f  0.66 f c 'bwd
material. For rectangular sections within aspect ratio h/b > (SI Units)
2.0, the effectiveness of the confinement shall be subject where bw is the web width. For rectangular sections with
to special analysis confirmed by test results. shear enhancement provided by transverse FRCM
8.3.3 Ductility Enhancement: The FRCM composite material, section corners must be rounded to a
3
composite material oriented essentially transversely to the radius not less than /4 inch (20 mm) before placement of
members’ axis may be used to enhance flexural ductility the FRCM material.
capacity of circular and rectangular sections where the 8.3.4.1 Limitations: To limit the total force per unit
ratio of longer to shorter section dimension does not width transferred to the concrete, the increment in shear
exceed 2.0. The enhancement is provided by increasing strength provided by the FRCM reinforcement shall not
the effective ultimate compression strain of the section as exceed 50% of the original capacity.
computed in Equation (19).
9.0 EVALUATION REPORT RECOGNITION
8.3.4 Shear Strength Enhancement of Concrete
Elements: The FRCM composite material bonded to The evaluation report shall include the following:
surfaces of reinforced concrete members with the fiber 9.1 Basic information required by Section 2.0 of this
strands oriented essentially perpendicular to the members’ criteria, including product description, installation
axis may be used to enhance the design shear strength by procedures, packaging and identification information, and
acting as external shear reinforcement. Shear material properties as determined in Section 4.0 of this
strengthening using external FRCM may be provided at criteria.
locations of expected plastic hinges or stress reversal and
for enhancing post-yield flexural behavior of members in 9.2 A statement that design and installation must be in
moment frames resisting seismic loads only by completely accordance with the published ICC-ES report, the
wrapping the section. Only continuous FRCM U-wraps or approved quality documentation, the Design Manual, and
the IBC.
continuous complete wraps shall be considered.
9.3 A statement that copies of quality documentation
The design tensile strain in the FRCM shear
and the Design Manual must be submitted to the code
reinforcement, εfv, shall be calculated by Equation (23):
official for each project using the systems.
εfv = κv εfu ≤ 0.004 (23) 9.4 A statement that complete construction
documents, including plans and calculations verifying
@Seismicisolation
@Seismicisolation
9
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

compliance with this report, must be submitted to the code Vn = nominal shear strength, lb (N)
official for each project at the time of permit application.
Vs = contribution of the steel reinforcement to the
The construction documents must be prepared and sealed
nominal shear strength, lb (N)
by a registered design professional where required by the
statutes of the jurisdiction in which the project is to be b = short side dimension of the compression
constructed. member with rectangular cross section, in.
(mm)
9.5 A statement that special inspection for jobsite
application of the systems must be provided in accordance bw = web width, in. (mm)
with Section 6.2 of this criteria. d = distance from extreme compression fiber to
9.6 If there is testing in accordance with Section 4.9 of centroid of tension reinforcement, in. (mm)
this criteria, a statement about the effect of the FRCM fc = compressive stress in concrete, psi (MPa)
system on the fire-resistance rating of the concrete or
masonry structure. Otherwise, there must be a statement f′c = specified compressive strength of concrete,
that the fire-resistance rating of the strengthened structure psi (MPa)
is outside the scope of the evaluation report. f′cc = maximum compressive strength of confined
9.7 If the system is tested in accordance with Section concrete, psi (MPa)
4.10 of this criteria, a statement about the flame spread f′co = compressive strength of unconfined
and smoke developed indices for the system. concrete; also equal to 0.85f’c, psi (MPa)
10.0 NOMENCLATURE: ffe = effective tensile stress level in FRCM
Ac = net cross-sectional area of the compression composite material attained at failure, psi
2 2 (MPa)
member, in. (mm )
2 ffu = ultimate tensile strength of the FRCM
Ae = area of the effectively confined concrete, in.
2 composite material, psi (MPa)
(mm )
Af = area of grid reinforcement by unit width, ffv = design tensile strength of the FRCM shear
2 2 reinforcement, psi (MPa)
in. /in (mm /mm)
Ag = gross cross-sectional area of the ffs = tensile stress in the FRCM reinforcement
2 2 under service load, psi (MPa)
compression member, in. (mm )
2 fl = maximum confining pressure due to FRCM
As = area of longitudinal steel reinforcement, in.
2 jacket, psi (MPa)
(mm )
D = diameter of the compression member, in. fss = tensile stress in the steel reinforcement
(mm) under service load, psi (MPa)
E2 = slope of linear portion of stress-strain model fy = steel tensile yield strength, psi (MPa)
for FRCM-confined concrete, psi (MPa) h = long side dimension of the compression
Ec = modulus of elasticity of concrete, psi (MPa) member with rectangular cross section, in.
(mm)
Ef = tensile modulus of elasticity of the cracked
FRCM composite material specimen, psi n = number of layers of grid reinforcement
(MPa) r = radius of the edges of a rectangular cross
H = height of the masonry wall, in. (mm) section confined with FRCM, in. (mm)
L = length of the wall in the direction of the t = thickness of the masonry wall in. (mm)
applied shear force, in. (mm) εc = compressive strain level in the concrete,
Mf = contribution of the FRCM composite material in./in. (mm/mm)
to the nominal flexural strength, in-lb (N-mm) ε'c = compressive strain of unconfined concrete
Mm = contribution of the reinforced masonry to the corresponding to f'c, in./in. (mm/mm); may be
nominal flexural strength, in-lb (N-mm) taken as 0.002
Mn = nominal flexural strength, in-lb (N-mm) εccu = ultimate compressive strain of confined
concrete corresponding to 0.85f'cc in a lightly
Ms = contribution of the steel reinforcement to the confined member (member confined to
nominal flexural strength, in-lb (N-mm) restore its concrete design compressive
Vc = contribution of the concrete to the nominal strength), or ultimate compressive strain of
shear strength, lb (N) confined concrete corresponding to failure in
a heavily confined member
Vf = contribution of the FRCM composite material
to the nominal shear strength, lb (N) εfd = design tensile strain of the FRCM composite
material, in./in. (mm/mm)
Vm = contribution of the (unreinforced or
reinforced) masonry to the nominal shear εfe = effective tensile strain level in FRCM
strength, lb (N) composite material attained at failure, in./in.
(mm/mm)
@Seismicisolation
@Seismicisolation
10
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

εfv = design tensile strain of the FRCM shear Κa = efficiency factor for FRCM reinforcement in
reinforcement, in./in. (mm/mm) the determination of f’cc (based on the
geometry of the cross section)
εfu = ultimate tensile strain of the FRCM
composite material, in./in. (mm/mm) Κb = efficiency factor for FRCM reinforcement in
the determination of εccu (based on the
εsy = steel tensile yield strain, in./in. (mm/mm) geometry of cross section)
εt = net tensile strain in extreme tension steel Κv = bond-reduction coefficient for shear
reinforcement at nominal strength, in./in.
μ = displacement ductility level, defined relative
(mm/mm)
to yield or cracking displacement.
ε't = transition strain in the stress-strain curve of Ψf = additional strength reduction factor for FRCM
FRCM-confined concrete, in./in. (mm/mm) confined concrete
ᶲm = strength reduction factor for flexure ρg = ratio of the area of longitudinal steel
ᶲv = strength reduction factor for shear reinforcement to the cross-sectional area of
a compression member (As/bh).■

TABLE 1—SUMMARY OF MATERIAL TESTS REQUIRED FOR EACH FRCM SYSTEM 1

GRID CONDITIONING TEST TYPE HOURS NUMBER OF REPLICATES AC 434 SECTIONS

Dry shrinkage 5 4.2.1
Continuous
Void content 5 4.2.2
total 10
Ambient 5
Direct tension 4.2.3
Freeze/thaw 5
Continuous 4.4
Ambient 5
Inter. shear 4.2.4
Freeze/thaw 5
total 20
Ambient 5
Water 5
1,000
Saltwater 5
Alkali 5
Direct tension 4.2.3
Ambient 5
Water 5
3,000
Saltwater 5
Alkali 5
Continuous 4.5
Ambient 5
Water 5
1,000
Saltwater 5
Alkali 5
Inter. shear 4.2.4
Ambient 5
Water 5
3,000
Saltwater 5
Alkali 5
total 80
Ambient 5
Continuous Direct tension 4.2.3 4.6
Fuel 5
total 10
Ambient 5
Water 5
1,000
Saltwater 5
Alkali 5
Lap Direct tension 4.2.3 4.5 4.7
Ambient 5
Water 5
3,000
Saltwater 5
Alkali 5
total 40
Ambient 5
Water 5
1,000
Saltwater 5
Alkali 5
Continuous bond 4.8
Ambient 5
Water 5
3,000
Saltwater 5
Alkali 5
total 40
1
See Section 4.0 of this criteria for details.
@Seismicisolation
@Seismicisolation
11
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

TABLE 2—ENVIRONMENTAL DURABILITY TESTS

PERCENT RETENTION
ENVIRONMENTAL RELEVANT
TEST CONDITION TEST DURATION Hours
DURABILITY TEST SPECIFICATION
1,000 3,000
ASTM D 2247
Water resistance 100%, 100 ± 2°F
ASTM E 104
ASTM D 1141 Immersion at
Saltwater resistance
ASTM C 581 73 ± 2°F 1,000 and 3,000
85 80
Immersion in hours
solution with pH =
Alkali resistance
9.5 or higher and
73 ± 3°F

TABLE 3—CREEP RUPTURE STRESS LIMITS FOR REINFORCEMENT BASED ON FIBER TYPE

FIBER TYPE
PARAMETER
AR Glass Aramid Carbon PBO
Creep rupture 0.20fu 0.30fu 0.55fu 0.30fu

FIGURE 1—TEST SEQUENCE OF IMPOSED DISPLACEMENT

@Seismicisolation
@Seismicisolation
12
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

FIGURE 2—STRESS-STRAIN DIAGRAM FOR FRP-CONFINED CONCRETE

FIGURE 3—EQUIVALENT CIRCULAR CROSS SECTION

@Seismicisolation
@Seismicisolation
13
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

Annex A

Tensile Testing of Fiber-reinforced Cementitious Matrix (FRCM) Composite Specimens

A1.0 Summary of Test Method

A thin flat strip of material having a near-constant rectangular cross section is mounted in the grips of a mechanical testing
machine and loaded with monotonically increasing load in tension while recording load and movement. The ultimate strength
of the material can be determined from a maximum load carried before failure. The coupon strain or elongation is monitored
with displacement transducers to determine the nominal stress-strain response of the material, and from that the cracking
stress and strain, ultimate tensile strain, tensile modulus of elasticity before and after cracking of cement-based matrix can be
derived.
This test procedure is designed to produce tensile property data for material specifications, quality assurance, and structural
design and analysis. Factors that influence the tensile response and shall therefore be reported include the following: material,
methods of material preparation and lay-up, specimen preparation, specimen conditioning, environment of testing, specimen
alignment and gripping, and speed of testing. Properties, in the test direction, which may be obtained from this test include:
1. Ultimate tensile strength
2. Ultimate tensile strain
3. Tensile modulus of elasticity of uncracked specimen
4. Tensile modulus of elasticity of cracked specimen
5. Transition point
Attention shall be paid to material and specimen preparation, gripping, and test system alignment. Poor material fabrication
practices, lack of control in alignment of fiber grid, and damage induced by improper cutting and machining the coupons are
known causes of high material data scatter. Specimen gripping problems can also cause a high percentage of grip-influenced
failures and therefore more scatter in data. Every effort shall be made to eliminate excess bending due to system
misalignment and out-of-tolerance conditions caused by poor specimen preparation.
A2.0 Apparatus
A2.1 Dimension Measurements: The accuracy of instruments used for measuring dimensions of the test specimens
shall be suitable for reading to within 1 percent of the sample dimensions.
A2.2 Testing Machine: The testing machine shall be in conformance with Practices ASTM E 4. The testing machine
shall have both an essentially stationary head and a movable head. The drive mechanism shall be capable of imparting to the
movable head a controlled velocity with respect to the stationary head. The testing machine load sensing device shall be able
to indicate the applied load to the specimen within 1 percent of the indicated value. Each head of the testing machine shall
carry one grip for holding the test specimen in coincident with the longitudinal axis of the specimen. The grips shall apply
sufficient lateral pressure to prevent slippage between the grip face and the coupon. It is desirable to use grips that are
rotationally self-aligning to minimize bending stresses in the coupon.
A.2.3 Strain Indicating Device: An extensometer satisfying Practice ASTM E 83, Class B-1 requirements can be used
for strain/elongation measurement. A minimum gage length of 2 inches (50 mm) shall be used. Since the coupon undergoes
cracking in the early stages of loading, the gage length shall be adequate to at least include within itself one transverse crack.
The bearing points of the extensometer on the coupon shall not be disturbed by cracking. If cracking occurs at the bearing
points, the specimen shall be unloaded and extensometer moved. The discontinuity in elongation reading can be removed in
data reduction process by matching the stop and restart point or similar means. The weight of extensometer shall not cause
significant bending in the specimen.
A3.0 Test Specimens
At least five specimens shall be tested per test condition. Specimens can be cut from larger panels laid up in special molds.
Control of fiber grid alignment is critical in lay-up procedure. Effective cutting tools and methods need to used, and precautions
shall be taken to avoid notches, undercuts, uneven surfaces, or delaminations. The specimen preparation method shall be
reported. Specimens shall be labeled properly to be distinct from each other and traceable to the raw material.
The test specimens shall be rectangular coupons. The thickness of coupons shall be as required and be a function of number
of layers and thickness of matrix for each layer. The width of the coupon shall be adequate to include a minimum number of
strands (e.g., three3 strands in each layer) and shall not be less than four times the thickness of the specimen. The width shall
also be kept as a multiple of the grid spacing. Also, in case the strands in different layers are staggered with respect to each
other, it is preferable to have the same number of strands in each layer along the width of the coupon. The minimum length of
the coupon shall include gripping distance, plus twice the width plus gage length. Longer lengths are preferred to minimize the
bending effects on the specimen.
Metallic tabs (e.g., steel, aluminum) are recommended for gripping to avoid damage to the specimen by grips. The tabs can be
glued to the specimen ends (two at each end, one at each face). The tabs shall have the same width as the coupon. The tab
length can be calculated based on the maximum expected tensile load, glue and tab bond strength to the matrix, and
@Seismicisolation
@Seismicisolation
14
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

development length of the fiber strands within matrix. A minimum of 3 inches (75 mm) tab length is recommended. The
thickness of the tabs shall be adequate to distribute uniformly the gripping force to the overall width of the coupons. A
1
minimum thickness of /16 inch (2 mm) is recommended.
A4.0 Calibration
The accuracy of all measuring equipment shall have certified calibrations that are current at the time of use of the equipment.
A5.0 Conditioning
Unless a different environment is specified as part of the experiment, test specimens shall be moist cured at least for seven
days after lay-up, and another seven days at laboratory environment before testing. Tests can be conducted at 14-day age
and later. Storage after curing and testing shall be at standard laboratory atmospheric conditions.
A6.0 Procedure
After conditioning and before testing, coupon type and geometry and environmental conditioning test parameters are specified.
The overall cross-sectional area of the specimen is calculated as follows:
A = ws h s (A1)
where ws is the nominal width and hs is the nominal thickness of the coupon. The width and thickness are measured at three
locations along the specimen and averaged. This value is determined for reporting purposes only. For computation of FRCM
2 2
mechanical properties, the area of grid reinforcement by unit width, Af measured in. /in (mm /mm), as reported by the
manufacturer, is used.
Special tabs prepared for installation are glued to the specimen. The glue shall be permitted to cure per applicant instruction.
The specimen placed in the grips of testing machine, taking care to align the axis of the gripped specimen with the test
direction. If applicable, the grips are tightened. An initial minimal tension, less than 5 percent of the anticipated failure load, is
applied to straighten potential bow in the specimen. The displacement transducer is attached to the specimen, preferably
symmetrically about the mid-span, mid-width location. The load is applied under displacement control. The loading rate can be
adjusted by the velocity of the machine head. A standard rate of 0.01 in./min (0.2 mm/min) is recommended.
The load versus displacement shall be recorded continuously or at frequent regular intervals. The load, displacement, and
mode of cracking (or any other damage) during testing that would cause transition region in otherwise a linear response are
recorded. Cracks may occur at regular spacing along the specimen. If the cracks intercept the transducer bearing points, the
specimen shall be unloaded to the level of the initial loading. The displacement transducer shall then be slightly moved and
reinstalled to bear at uncracked region of the matrix. Reload the specimen with the same rate of loading and continue data
recording. The displacement transducer shall be removed before anticipated failure to avoid damage to the sensor, but load
readings shall continue until failure. The maximum load, the failure load, and corresponding displacements at, or as near as
possible to, the moment of rupture shall be recorded, along with the failure mode and location.
A7.0 Calculation
The recorded data shall be reduced to reflect the initial tensile loading and reading discontinuity if the transducer were to be
moved during the test. This will likely result in a near bilinear response curve (Figure A1) with an initial line for uncracked
specimen, a secondary line for cracked specimen, and possibly a curved transition segment in between.
A7.1 Expected Tensile Stress – Strain Curve: The expected tensile stress, ff, versus tensile strain, εf, curve of an
FRCM coupon specimen is shown in Figure A1. If a curved segment exist in between two linear portions of the response
curve, the two lines to initial and secondary segments of the response curve shall be continued until they intersect. The
displacement and load corresponding to the intersection are calculated as the transition point data, named T in Figure A1.

@Seismicisolation
@Seismicisolation
15
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

FIGURE A1—EXPECTED TENSILE STRESS VERSUS TENSILE STRAIN CURVE OF AN FRCM COUPON SPECIMEN.
THE TRANSITION POINT T IS INDICATED
In Figure A1 the following quantities are shown:
Ef = tensile modulus of elasticity of the cracked specimen, psi (MPa)
E f* = tensile modulus of elasticity of the uncracked specimen, psi (MPa)
ffi = tensile stress at ith data point, psi (MPa)
ffu = ultimate tensile strength, psi (MPa)
fft = tensile stress corresponding to the transition point, psi (MPa)
εfi = tensile strain at ith data point, in./in. (mm/mm)
εfu = ultimate tensile strain, in./in. (mm/mm)
εft = tensile strain corresponding to the transition point, in./in. (mm/mm)
A7.2 Transition Point (T): If a curved segment exist in between two linear portions of the response curve, the two lines
to initial and secondary segments of the response curve shall be continued until they intersect. The displacement and load
corresponding to the intersection are calculated as the transition point data.
A7.3 Tensile Stress/Tensile Strength: The ultimate tensile strength and, if needed, the tensile stress at a specific data
point are calculated using the following equations:
ffu = Pmax / (Af ws) (A2)
ffi = Pi / (Af ws) (A3)
where:
Pmax = maximum load before failure, lbf (N).
Pi = load at ith data point, lbf (N).
2 2
Af = area of grid reinforcement by unit width, in. /in (mm /mm)
ws = nominal width of the specimen , in. (mm)
A7.4 Tensile Strain: Tensile strain at a specific data point is calculated using the following equation:
εfi = i / Lg (A4)
where:
δi = extensometer displacement at ith data point, in. (mm).
Lg = extensometer gage length, in. (mm).
A7.5 Tensile Modulus of Elasticity of Uncracked Specimen: On the linear segment of the initial line of the response
bilinear curve corresponding to uncracked behavior of the specimen two points connecting the results in a line that closely
follows the trend and slope of the response curve at that region are selected. The tensile modulus of elasticity of the
uncracked specimen is calculated using:
Ef* = f /  (A5)
@Seismicisolation
@Seismicisolation
16
ACCEPTANCE CRITERIA FOR MASONRY AND CONCRETE
STRENGTHENING USING FIBER-REINFORCED CEMENTITIOUS
MATRIX (FRCM) COMPOSITE SYSTEMS (AC434)

where:
f = difference in tensile stress between two selected points, psi (MPa).
 = difference in tensile strain between two selected points, in/in (mm/mm).
Alternatively, the slope of the initial line passing through the origin and drawn to obtain the transition point on the response
curve can be calculated as the modulus of elasticity of uncracked specimen.
A7.6 Tensile Modulus of Elasticity of Cracked Specimen: On the linear segment of the secondary line of the
response bilinear curve corresponding to cracked behavior of the specimen two points connecting the results in a line that
closely follows the trend and slope of the response curve at that region are selected. The tensile modulus of elasticity of the
cracked specimen is calculated using:
Ef = f /  (A6)
Alternatively, the slope of the secondary line drawn to obtain the transition point on the response curve can be calculated as
the modulus of elasticity of cracked specimen.
A7.7 Ultimate Tensile Strain: Ultimate tensile strain, εfu, is calculated by extrapolating the secondary line in the bilinear
response curve, or using the following equation:
fu = ft +(ffu  fft) / Ef (A7)
A8.0 Report
The following information shall be reported to the maximum extent applicable:
 Date and location of the test
 Name of test operator
 Any variations to this test method
 Identification of the material tested including material specification, type, and designation, manufacturer
 Description of the fabrication steps used to prepare the composite material including fabrication date, process, cure
cycle, and description of equipment used
 Orientation of the fiber grid
 Area of grid reinforcement by unit width and nominal cross-section area of all specimens
 Method of preparation of test specimen including labeling system, geometry, sampling method, cutting, tab
identification, geometry and adhesive used
 Calibration information for all measurement and test equipment
 Description of the test machine
 Conditioning parameters and results
 Temperature and humidity of testing laboratory
 Number of specimens tested
 Speed of testing
 Type and placement of transducers on the test specimens
 Stress-strain curve and tabulated results
 Individual strengths, average, standard deviation, and coefficient of variation (in percent) for the population
 Individual strains at failure and average, standard deviation, and coefficient of variation (in percent) for population
 Strains used for modulus calculation
 Describe the method used for calculation of the moduli of elasticity
 Individual moduli of elasticity and average, standard deviation, and coefficient of variation (in percent) for population
 If transition strain is determined, describe the method of linear fit
 Individual values of transition strains and average, standard deviation, and coefficient of variation (in percent) for
population
 Failure mode and location of failure for each specimen.

@Seismicisolation
@Seismicisolation
17