Analysis of Mechanical and Durability Properties of Fly Ash Concrete by

Enhancing Slag Content

Abstract
The cement industry is a non-eco-friendly environment because of CO 2 nonstop emission
at the raw material production which is based on cement production procedure. This paper
analyses the basic mechanical and durability assets of M50 strength score Heavy Weight
Concrete (HWC) by the spare of cement through slag at 40-60% and fly ash at 15-35% levels.
The flexural, elastic modules, durability assets, split tensile and compressive strength are
involved water permeability and drying shrinkage behavior. Through lengthy curing enhances
the mechanical and water permeability strength of slag and fly ash HWC. To evaluate the elastic
modules of slag and fly ash, a simple connection is employed based on HWC from its
compressive strength and density. The slag and fly ash concretes enhanced mechanical assets
enhanced and permeable voids volume is minimized. The fly ash concrete has low resistance to
chloride penetration because its high permeable voids volume. The results show a long-tern
drying shrinkage strain for every fly ash based on 15-35% of HWC is smaller than 100% of
Ordinary Portland Cement (OPC). It is tough density variations of slag and fly ash concretes
shows to long-term managed environment and it is used to measure the HWC members shielding
thickness among ionizing radiations.

Keywords: Compressive Strength, Fly Ash, Heavy Weight Concrete, Mechanical and
Durability Properties, Ordinary Portland Cement.

1. Introduction
The concrete is extensively used material for creation because of admirable performance
of workability and compressive strength. The workable concrete strength has enhanced through
fibers and rebar [1]. Because of the huge development of urbanization, the concrete consumption
has enhanced progressively which is applied as important construction material. Moreover, the
OPC is used as initial cementitious material of concrete [2]. The universal consumption of OPC
is enhanced by 1.3 billion tons from 1880-1990 and every tone of residue generated issues
approximately 850kg of carbon dioxide to environment [3]. To minimize negative creation
influence cement situation, which is crucial to found substitute material that partially or fully
replaced by cement [4]. It is attained through limited spare cement, geopolymer concrete by
Supplementary Cementitious Materials (SCMs) and nanomaterial integration for maintainability
[5]. The compositional features allow the fly ash application in cement-based constituents.
Through enhancing reduction and shortage sources for human construction, solid waste creation
in concrete industry [6]. The fly ash has examined as alternative raw material in cement creation
and it has merged in cement as SCM. Through fly ash chemical composition is majorly based on
its various sources that creates it as challenging for cement production [7]. Contribution of the
paper is given as follows:
  The fly ash slag proportion concretes enhanced mechanical assets enhanced and
permeable voids capacity is minimized. The fly ash concrete has low resistance to
chloride penetration because its high permeable voids volume.
 Mixes with enhanced slag has same resistance to chloride penetration than OPC.
Therefore, OPC ability is to bind chloride, then it is efficient to preserve embedded steel
from corrosion.
 The fly ash or slag content has enhanced resistance compared to OPC that is due to less
calcium and creation of silicate rich gel which minimized the following rate and mass
losses.
Rest of paper is decided as follows: Section 2 contains a literature review, section 3
indicates proposed method, section 4 represents results, and section 5 determines conclusion.

2. Literature Review
Jianhe Xie et al. [8] developed an Impact behavior of slag and fly ash-based geopolymer
concrete with the impact of recycled aggregate concrete, curing age and water-binder ratio. The
model goal to analyzed compressive behavior of GRAC based slag fly ash which focused on
binder water ratio (0.30-0.5), curing age (7 and 28days) and Recycled Coarse Aggregate (RCA)
content (0%, 50%, 100%). Through the 100mm pressure kit, with the GRAC impact properties
under various strain rates of 30s-1 to 150s-1. The GRAC compressive assets under stress-stain
curves, modes failure, energy absorption ability and compressive strength are developed and
associated to quasi-static loading.
Katarzyna Konieczna et al. [9] introduced an analysis of mechanical properties,
microstructure and durability of low-clinker huge concrete performance integrating Ground
Granulated Blast Furnace Slag (GGBFS), Silica Fume (SF) and Siliceous Fly Ash (SFA). The
highest number of cement clinker from CEM differed from 64-116kgg in a concrete mixture of
1m3. HPC compressive strength like after casting 2years and 2, 7, 14, 28, 56, 90 days are
considered for testing. The water penetration depth under internal frost and pressure resistance at
test are estimated after curing 56 days, moreover concrete pH values are accomplished.
V Venkitasamy et al. [10] implemented mechanical and durability assets of M50 strength
score HWC by spare of cement through slag at 40-60% and fly ash at 15-35% stages. The
flexural, elastic modules, durability assets, split tensile and compressive strength are involved
water permeability and drying shrinkage behavior. Through lengthy curing enhances the
mechanical and water penetrability strength of slag and fly ash HWC. To evaluate elastic
modules of slag and fly ash, a simple connection is employed based on HWC from its
compressive strength and density.
Zhiwei Qu et al. [11] suggested a different fly ash and GGBFS content on concrete
property modeling. The mechanical properties in time expansion of concrete mixtures with
different GGBFS and fly ash are analyzed. It included four various cement replace levels like
0%, 20%, 30% and 40% through fly ash and GGBFS. The compressive, flexural, splitting tensile
strength of concrete was estimated for 28days. Three extra concrete mixtures with ternary
binders are analyzed the early age shrinking growth of 28 days. Moreover, prediction model in
previous standards was considered to estimate the performance.
Gritsada Sua-iam and Natt Makul [12] presented a focus on chloride migration Self
Compacting Concrete (SCC) with pozzolans named as FA and SF with RCA. The effects of
exterior power potential and RCA on features of SCC are analyzed with influence materials
which focus on chloride mitigation coefficient and properties. The SCC mixtures created through
various proportions of FA and SF. Additionally, integrating SCC and RCA mixtures influences
coefficient levels. The behavior highlights the significance of RCA for enhancing SCC resistance
chloride which was crucial factor for long-time duration.

3. Materials and Mixture Design

3.1 Materials
The OPC 43 grade compatible to IS 269:2015 is utilized to concrete and fine aggregates
and heavy coarse are sieved and crushed from hematite iron boulders. The hematite aggregates in
physical properties are given in table 1. The physical and chemical properties of OPC, fly ash
and GGBS generated by constructors are presented in table 2.
Table 1. Physical properties of hematite aggregation

Aggregate Specific Water Flakiness Crushing Impact value

size (mm) gravity absorption (%) value (%) (%)
(%)
20 4.72 0.75 7.37 13.20 7.28
12.5 4.70 1.10 7.15 - -
<4.75 4.40 2.95 - - -

Table 2. Physical and chemical properties of Binder

Binder Batch Chemical composition weight (%) Specific Blaine

no SiO2 Al2O3 Fe2O3 CaO MgO gravity surface
area
(m2/kg)
Cement 1 21.8 5.45 4.53 61.31 1.31 3.17 313
2 21.7 5.49 4.54 61.57 1.12 3.19 301
GGBS 1 34.7 20.08 0.59 35.79 6.39 2.92 368
2 34.6 20.08 0.65 35.80 6.05 2.91 361
Fly ash 1 62.5 30.9 1.1 0.9 0.52 2.07 334
2 62.6 33.4 1.3 1.9 1.23 2.02 339
 The chemical admixture of Polycarboxylate Ether (PCE) brand A contains 34% compact
content and 1.1 specific gravity are used after checking compatibility with fly ash and OPC
binder integrations. Subsequently PCE brand A is not companionable by GGBS and OPC binder
integration, PCE chemical admixture brand B contains 34.5% solid content and 1.1 specific
gravity is used for binary GGBS mix.
3.2 Mixture Design
The balanced mixture design is based on HWC mixture propagation in M50 strength
grade by concreate difficult state density that is not smaller than 3600kg/m 3. The Heavy Fine
Aggregates (HFA) and Heavy Coarse Aggregate (HCA) is handled in condition of Saturated
Surface Dry (SSD). Through 0.39 water binder ratio, M50 compressive strength grade is
occurred trails by actual OPC. Moreover, the OPC is substitute by less calcium GGBS upto 60%
and fly ash upto 35% through mass in HWC mixtures. The highest work-capability of final
proportion slump of HWC is attained through including highest dosage that unable to results in
variabilities in actual concrete. The primary slump of HWC mix is 130mm and find difference
from100-130mm for OPC replacement by GGBS (40-60%) and 150-180mm for OPC
replacement by fly ash (15-30%). The actual mixture air content is tested based on IS 1199 that s
finds by 0.2% of HWC control among 0.3-0.9% and 15-35% fly ash, among 0.9-1.7% for 40-
60% slag spare. In identity mix generated, the H denotes HWC and following letter denotes the
binder type like slag or fly ash of mixture. The following number denotes mass percentage level
in mixture.

4. Results
In this section, figure 1 presents VPV for concrete mix after curing 28 and 180days,
figure 2 Compressive strength for concrete mix after 1, 7 and 28days. The table 3 resistivity and
chloride migration coefficients for concrete mix after 28days. The fly ash concrete has low
resistance to chloride penetration because its high permeable voids volume. Mixes with
enhanced slag has same resistance to chloride penetration than OPC. Therefore, OPC ability is to
bind chloride, then it is efficient to preserve embedded steel from corrosion. The fly ash or slag
content has enhanced resistance compared to OPC that is due to less calcium and creation of
silicate rich gel which minimized the following rate and mass losses.
 Figure 1. VPV for concrete mix after 28 and 180days
Figure 1 presents VPV for concrete mix after curing 28 and 180 days, the error denotes
standard deviation estimated from three samples. Highest VPV scores are denoted for 100% fly
ash that minimized slag. It denotes low porous microstructure as increased slag content. It
happens because of space filling creation C-A-S-H and C-N-A-S-H are related to N-A-S-H
which is created in fly ash of 100%. The OPC has same VPV as fly ash of 30% and slag of 70%
blend. After completing 180 days, the VPV score is minimized for every mix. It is much
noticeable for mixture with high slag content because of continuous growth of microstructure
which is restricted for flowing reactions which considers fly ash of 100% after finishing curing.

Figure 2. Compressive strength for concrete mix after 1, 7 and 28days

 Figure 2. Compressive strength for concrete mix after curing 1, 7 and 28days, the error
denotes standard deviation estimated from three samples. The 100% of fly ash obtain 50% of its
28day strength within initial 24 hours because of high temperature curing. The F100Ac has
28day strength of 48.5MPA matched to F100Bc of 16.0MPa that has huge activator content in
F100Ac. The 100% fly ash exhibited its higher compressive strength after curing 7days. It is
connected to high temperature elimination after curing 7days. In compressive strength, the minor
elimination is because of internal stresses as thermal shock output. The slag content enhanced to
64.0MPa after curing 28days for F30c. The PCc compressive strength 62.5MPa after 28days that
is same as F30c and F60c.
Table 3. Resistivity and chloride migration coefficients for concrete mix after 28days

Mix F100Ac F100Bc F80c F60c F30c PCc

Resistivity-28days 18.0 13.3 17.0 69.0 (5.9) 171.9 85.7
(Ωm) (0.7) (1.0) (0.1) (6.1) (2.1)
Chloride migration of >78.3 >83.4 46.3 7.1 (0.1) 3.9 (0.3) 11.1
concrete mix (1.3) (2.5) (4.2) (0.8)
( Dnssm ) ( 10−12 m2 /s )

Table 3 presents the coefficients of resistivity and chloride migration for concrete mix
after 28days. If the slag content enhanced the chloride coefficient is minimized to 46.3, 7.1 and
−12 2 −12 2
3.9 ×10 m /s. The OPC chloride coefficient is 11.1×10 m /s that has high resistance to
chloride penetration than F100Ac, F100Bc and F80c however few lesser resistances have
chloride penetration than F60c and F30c.The resistivity output denotes same trend by huge
resistivity attained for mixes by enhanced slag. It founds better correlation with VPV for every
mix and it minimized with enhanced slag. Likewise, if the resistivity enhanced, the chloride
migration is minimized as enhanced slag content. It denotes that mixes with enhanced slag has
high resistance for chloride penetration because of its minimized volume and enhanced
resistivity.

4.1 Discussion
The fly ash slag proportion concretes enhanced mechanical properties enhanced and
permeable voids capacity is minimized. The fly ash concrete has low resistance to chloride
penetration because its high permeable voids volume. Mixes with enhanced slag has same
resistance to chloride penetration than OPC. Therefore, OPC ability is to bind chloride, then it is
efficient to preserve embedded steel from corrosion. The fly ash or slag content has enhanced
resistance compared to OPC that is due to less calcium and creation of silicate rich gel which
minimized the following rate and mass losses. To evaluate the elastic modules of slag and fly
ash, a simple connection is employed based on HWC from its compressive strength and density.
The slag and fly ash concretes enhanced mechanical assets enhanced and permeable voids
volume is minimized. The fly ash concrete has low resistance to chloride penetration because its
high permeable voids volume.

5. Conclusion
This paper analyses the basic mechanical and durability assets of M50 strength score
HWC by the spare of cement through slag at 40-60% and fly ash at 15-35% levels. The flexural,
elastic modules, durability assets, split tensile and compressive strength are involved water
permeability and drying shrinkage behavior. Through lengthy curing enhances the mechanical
and water permeability strength of slag and fly ash HWC. To evaluate the elastic modules of slag
and fly ash, a simple connection is employed based on HWC from its compressive strength and
density. The slag and fly ash concretes enhanced mechanical assets enhanced and permeable
voids volume is minimized. The fly ash concrete has low resistance to chloride penetration
because its high permeable voids volume. The results show a long-tern drying shrinkage strain
for every fly ash based on 15-35% of HWC is smaller than 100% of OPC. It is tough density
variations of slag and fly ash concretes shows to long-term managed environment and it is used
to measure the HWC members shielding thickness among ionizing radiations. In future, the air
entertainment on freeze-thaw resistance efficiency of alkali-activated concerts.

References
[1] Xu, O., Han, S., Liu, Y. and Li, C., 2021. Experimental investigation surface abrasion
resistance and surface frost resistance of concrete pavement incorporating fly ash and
slag. International Journal of Pavement Engineering, 22(14), pp.1858-1866.
[2] Hosan, A. and Shaikh, F.U.A., 2021. Compressive strength development and durability
properties of high volume slag and slag-fly ash blended concretes containing nano-
CaCO3. Journal of Materials Research and Technology, 10, pp.1310-1322.
[3] Du, Y., Wang, S., Hao, W., Shi, F., Wang, H., Xu, F. and Du, T., 2022. Investigations of
the mechanical properties and durability of reactive powder concrete containing waste fly
ash. Buildings, 12(5), p.560.
[4] Mustakim, S.M., Das, S.K., Mishra, J., Aftab, A., Alomayri, T.S., Assaedi, H.S. and Kaze,
C.R., 2021. Improvement in fresh, mechanical and microstructural properties of fly ash-
blast furnace slag based geopolymer concrete by addition of nano and micro silica.
Silicon, 13, pp.2415-2428.
[5] Lim, Y.Y. and Pham, T.M., 2021. Effective utilisation of ultrafine slag to improve
mechanical and durability properties of recycled aggregates geopolymer concrete.
Cleaner Engineering and Technology, 5, p.100330.
[6] Hosan, A. and Shaikh, F.U.A., 2021. Influence of nano silica on compressive strength,
durability, and microstructure of high‐volume slag and high‐volume slag–fly ash blended
concretes. Structural Concrete, 22, pp.E474-E487.
 [7] Bellum, R.R., Al Khazaleh, M., Pilla, R.K., Choudhary, S. and Venkatesh, C., 2022.
Effect of slag on strength, durability and microstructural characteristics of fly ash-based
geopolymer concrete. Journal of Building Pathology and Rehabilitation, 7(1), p.25.
[8] Xie, J., Zhao, J., Wang, J., Fang, C., Yuan, B. and Wu, Y., 2022. Impact behaviour of fly
ash and slag-based geopolymeric concrete: The effects of recycled aggregate content,
water-binder ratio and curing age. Construction and Building Materials, 331, p.127359.
[9] Konieczna, K., Chilmon, K. and Jackiewicz-Rek, W., 2021. Investigation of mechanical
properties, durability and microstructure of low-clinker high-performance concretes
incorporating ground granulated blast furnace slag, siliceous fly ash and silica fume.
Applied Sciences, 11(2), p.830.
[10] Venkitasamy, V., Santhanam, M., Rao, B.P.C., Balakrishnan, S. and Kumar, A., 2024.
Mechanical and durability properties of structural grade heavy weight concrete with fly
ash and slag. Cement and Concrete Composites, 145, p.105362.
[11] Qu, Z., Liu, Z., Si, R. and Zhang, Y., 2022. Effect of various fly ash and ground
granulated blast furnace slag content on concrete properties: experiments and modelling.
Materials, 15(9), p.3016.
[12] Sua-iam, G. and Makul, N., 2024. Characteristics of non-steady-state chloride migration
of self-compacting concrete containing recycled concrete aggregate made of fly ash and
silica fume. Case Studies in Construction Materials, 20, p.e02877.