Materials Today: Proceedings 22 (2020) 894–896

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Materials Today: Proceedings

Study on autoclaved aerated concrete: Review

a r t i c l e i n f o a b s t r a c t

Article history: Aerated lightweight concrete have many advantages when compared with conventional concrete such as
Received 21 May 2019 advanced strength to weight ratio, lower coefficient of thermal expansion, and good sound insulation as a
Received in revised form 5 November 2019 result of air voids within aerated concrete. Here by studying various research papers the change in prop-
Accepted 9 November 2019
erties of AAC has been studied and the production method is classified for each foamed and autoclaved
Available online 28 December 2019
concrete. The literature review of aerated lightweight properties is focus on the porosity, permeability,
compressive strength and splitting strength.
Keywords:
Ó 2019 Elsevier Ltd. All rights reserved.
Autoclaved aerated concrete (ACC)
Aluminium powder
Selection and peer-review under responsibility of the scientific committee of the International Confer-
Lightweight concrete ence on Materials Engineering and Characterization 2019.
Gypsum
Lime

1. Introduction and their use as creation substances can lead to enhanced perfor-
mance of AAC. The present study exhibits from the various recent
In a global view, Autoclaved Aerated Concrete (AAC) turned into literatures that the addition of materials and the fabrication of
first produced in Sweden inside the Nineteen Thirties and also can the AAC and their performance, strength in structural applications.
be referred to as mobile foamed concrete. The software has been
extended to large devices such as ground and partitions that have 2. Literature survey
a low weight Circulated air via cement (AAC) is one of the eco –
pleasant and warranted inexperienced structure substances. AAC Ali J. Hamad [1] Aerated lightweight concrete is unlike conven-
is the use of no aggregate is larger than sand. AAC is the aggregate tional concrete in additive materials and their properties. Aerated
of cement, sand, water, gypsum, lime and aluminium powder. The lightweight concrete does not have coarse aggregate, and it is pos-
chemical response of aluminium paste makes it a porous shape sess many advantages like low density with higher strength com-
having mild weight and greater insulation houses making one-of- pared to conventional concrete. The enhanced properties such as
a-kind from different mild weight concrete. The powdered zinc thermal and sound insulation, reduced dead load in could result
can also be delivered in area of aluminium powder. The silica flume several advantages in decrease structural elements and reduce
is used as additive materials in concrete mortar and cement. AAC the transferred load to the foundations and bearing capacity. This
consists of cementations mortar surrounding disconnected air is interest to categorize the aerated light-weight concrete into
voids and microscopic bubbles where in the air bubbles have been, foamed concrete and autoclaved concrete. A.M. Shende [2]; This
are the consequences of gas formed inside the mortar. Improving paper states that compressive energy, cut up tensile energy and
homes of creation subs. Today aerated concrete is produced flexural power are on better aspect for 3% fibres in assessment to
through cement is created by numerous organizations, especially that made from 0%, 1% and a pair of fibres. It was stated that higher
in Europe and Asia. There is some generation in the Americas and strength properties are observed at aspect ratio of 50 compare to
in Africa, there is one plant in Egypt. AAC creation in Europe has 60 and 70 percent. It was concluded that due to the addition of
backed off extensively, yet the business is developing quickly in steel fibres compressive strength, flexural, split tensile increases
Asia because of solid interest in lodging and business space. China by 11 to 24%, 12 to 49%, 3 to 41% respectively. Cheran [4] stated
is presently the biggest aircraft showcase on the planet with a that the Aerated lightweight concrete is different from conven-
few hundred manufacturing plants. China, Focal Asia, India, and tional concrete because of a few mix materials and their enhanced
the central East are the greatest regarding AAC assembling and uti- properties and. also found that Aerated lightweight concrete does
lization with the herbal volcanic materials have come to be massive no longer contain coarse combination. Several advantages in AAC

https://doi.org/10.1016/j.matpr.2019.11.099
2214-7853/Ó 2019 Elsevier Ltd. All rights reserved.
Selection and peer-review under responsibility of the scientific committee of the International Conference on Materials Engineering and Characterization 2019.
 M. Kalpana, S. Mohith / Materials Today: Proceedings 22 (2020) 894–896 895

blocks are decrease Aerated lightweight concrete is considering foam added, are prerequisites for the high thermal insulation
economy in materials and consumption and waste materials such capacity, high compressive strength, and relatively low permeabil-
as fly ash. In this have a look at the fabric residences and mechan- ity of the foam concrete. aerated concrete produced by adding alu-
ical properties of AAC blocks had been investigated from the liter- minum powder has some significant drawbacks, such as its
ature studies he found out the way to growth the bond strength relatively high cost as well as its lower strength, higher moisture
and flexural power in AAC and within the feature he can use AAC content, and more pronounced shrinkage when compared to tradi-
as a flexural member like beams. tional concrete. The properties of aerated concrete can be consider-
Parth Desani [3], says that manufacturing of various mixed ratio ably improved by autoclave high-pressure steam curing.
of whole concrete blocks from dewatered water treatment sludge Ayudhya [12] experimented in his research that the change in
used as a quality aggregate in hollow concrete blocks, might be a the insight of the strength of AAC addition with PP fiber reinforce-
profitable disposal opportunity inside the future. And also found ment at elevated temperatures (up to 1000 °C). It was found that
that using AAC as alternative materials can be economically prof- the specimens with perlite were analysed of their residual strength
itable. Khandve [5], This paper shows Compressive strength of under various temperatures. It was found that residual compres-
AAC blocks is relatively greater than traditional clay brick. These sive strength decreased when the exposure temperature and the
are suitable for partitions in RCC framed building. Usage of fly amount of perlite replacement while increased. This was a poz-
ash ends in the reduction in the cement intake within the product zolanic effect due to sand proportion when specimens were sub-
which results in reduction of greenhouse gases. Density of AAC jected to high temperatures. It was a ratio of perlite mass
block is 1/3 that of traditional clay brick and there is no greater content to total aggregate (sand and perlite) mass content that
trade in wet circumstances. It enables in reducing useless load of reduced the loss in specimen strength (12). Replacement sand with
shape. Value of production reduces by means of most up to 20% perlite increased the unheated compressive and splitting tensile
as discount of useless load of wall on beam makes relatively lighter strength. 30% of addition provides the improved strength. In the
members. The electricity rate up inside the manufacturing method case of no fiber the compressive strength decreased when the con-
emits no pollutants and creates no by products or toxic waste mer- tent of perlite increased which was attributed to the transition
chandise. The work ability of AAC enables to eliminate waste at the amount of crystallization of tobermorite. The amount of perlite
jobsite. increased, the quantity of mixing waste also increased consider-
Mallampalli. Ch. G. Subash [6], Autoclaved aerated concrete is a ably which leads to decrement in strength performance. Yaseen
versatile light-weight creation material and typically used as Patel [13] In this study, different types of steel fibers were used
blocks. A low density and top notch insulation residences due to to produce fiber reinforced self-compacting concrete A strict mix-
high porosity. The low density is carried out by way of the forma- ing procedure is followed in this study, in terms of time of mixing,
tion of air voids to provide a cellular shape. The completed product addition of components, and sequence of material addition.
is as much as five instances the volume of the raw materials used, Ali Jihad [14] stated that, plain concrete (unreinforced concrete)
with an air content of 70–80% (depending on the required power breakdown suddenly when the deflection corresponding to the
and density.) without problems reasonable – can be saved, nailed ultimate flexural strength exceeded, oppositely FRC continues to
and drilled without problems even than timber. Gunasekaran [7] withstand considerable loads even at deflections significantly in
analysed that by using evaluating both, with lime and without excess of the fracture deflection of the plain concrete. The fractured
lime, got the surest fee of 1 g of aluminium powder with the aid specimens of FRC exhibits that failure takes place chiefly due to
of the use of with lime. The blocks were made by means of the fiber pull-out or debonding. Therefore, FRC specimen does not
usage of with lime mortar. Finally, it is economical and it gives break immediately after first crack this indicates increasing the
the good in compressive strength. work of fracture, which denoted to as toughness and represented
Anurag Wahane [8] He Achieved that The mild weight belong- by the area under the load-deflection curve. In this scenario ACC
ings of the AAC blocks effects into higher stability of the AAC blocks has improved fracture toughness and strength by its additions.
inside the shape of the homes. As the impact of the earthquake is Ali J. Hamad [1] the experimental findings indicate that the
immediately distributes proportional to the load of the building. increase of fiber content can produce stronger foamed concrete.
The building built using AAC blocks are more dependable and safer. The results of tests for compressive, splitting and flexural strength
AAC blocks are surprisingly advanced in terms of the strength. of glass fiber reinforced foamed concrete show significant
Higher level of power of those blocks offers higher balance to the increases when the percentages of glass fibers increase. The com-
structure of the building. AAC is manufactured from non- pressive and splitting tensile strength of autoclaved aerated con-
biodegradable substances, maintaining interiors smooth and crete (AAC) containing perlite aggregate and polypropylene fiber
sturdy. AAC block weighs almost around 8% less. Muthu Krishnan subjected to high temperatures. The polypropylene (PP) fiber con-
[9], Studied the behaviour Based on the experimental observation. tent of 0, 0.5, 1, 1.5 and 2% by volume was added to the mixture.
The mix proportion for Autoclave aerated concrete was achieved AAC could be better choice as Mostafa Jalal [16] highlighted that
and the fresh properties aggregate replacement by ceramic waste one of the disadvantages of SCC is its cost, associated with the use
provides good results in lightweight but the expected compressive of chemical admixtures and use of high volumes of Portland
strength can’t be achieved. The specimens cured in autoclave at cement. High cement content usually introduces high hydration
elevated temperature shows an increase in the compressive heat, high autogenous shrinkage and high cost. Moreover, the con-
strength and water absorption capacity by 10%. Good results are sumption of natural resources and carbon dioxide emissions asso-
expected to attain optimum temperature for autoclave curing. ciated with cement production can cause serious environmental
The results are to be compared both experimentally and analyti- impacts. Ghasem Pachideh [17] concluded that use of pozzolanic
cally. Manikandan [10] On this observation Aerated light weight materials in autoclaved aerated concrete improves the compres-
concrete is unlike conventional concrete due to some mix materi- sive strength in such a way that replacement of silica fume, zeolite
als and properties. Several advantages in AAC blocks are decrease and granulated blast-furnace slag could improve the compressive
structural elements and reduce the bearing capacity. In this study strength by 84, 200 and 72%, respectively. Interestingly, it was
the material properties and mechanical properties of AAC blocks observed when great ratios of pozzolans are applied (21%), silica
were investigated. fume improves the strength slighter in contrast to the granulated
Viacheslav Markin [11] However, a dense matrix structure in blast furnace slag. it was found that use of silica fume in autoclaved
conjunction with isolated large air voids, which stem from the aerated concrete lessens the water absorption. Based on the
896 M. Kalpana, S. Mohith / Materials Today: Proceedings 22 (2020) 894–896

results, after the passage of 10, 30 and 90 min, the water absorp- [2] A.M. Shende1, A.M. Pande2, M. Gulfam Pathan, Experimental Study on Steel
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[14] Ali Jihad Hamad, Rami Joseph, Aghajan Sldozian, Flexural and flexural
building subjected to earthquake loading. AAC blocks region unit
toughness of fiber reinforced concrete-American standard specifications
extremely superior in terms of the electricity. Higher level of elec- review, Global Res. Development J. Eng. 4 (3) (2019), ISSN: 2455-5703.
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Comparative study on effects of Class F fly ash, nano silica and silica fume
building. AAC is manufactured from non-biodegradable materials
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Declaration of Competing Interest [18] Ling Qin, Xiaojian Gao, Recycling of waste autoclaved aerated concrete powder
in Portland cement by accelerated carbonation, Waste Management 89 (2019)
The authors declare that they have no known competing finan- 254–264.

cial interests or personal relationships that could have appeared

[15] Ali J. Hamad, Materials, production, properties and application of aerated

[1] Ali J. Hamad, Materials, production, properties and application of aerated