Introducing a Method to Determine Nonautoclaved AeratedConcrete Air content Based on Packing Theory

Mohsen Mohammadi1; Ali Akbar Shirzadi Javid2; and Mehdi Divandari3

Abstract: This paper presents an experimental study on fresh and hardened properties of nonautoclaved aerated concrete (NAAC) mixtures.It also attempts to address a new method to determine the packing density and air percentage of NAAC mixtures. Different types of NAACmixtures with various aluminum powder percentages and water-to-cement ratios were made. Results revealed that the new method (called thewet packing theory) is able to determine the percentage of air pores in the aerated concrete with high accuracy. Results also showed that thereis an optimum aluminum percentage of approximately 0.0934 from the perspective of minislump diameter and compressive strength. With anincrease in the aluminum percentage compared to the optimum percentage, minislump (workability and flow-ability) and compressivestrength reduced. Scanning electron microscope (SEM) images of NAAC indicated that the air voids were shaped as an artificial porosity.The results showed that with an increase in the amount of aluminum powder, packing density reduced. It was observed that the maximumair percentage increased with an increase in the amount of aluminum percentage from 0.0934 to 0.1869. DOI: 10.1061/(ASCE)MT.1943-5533.0002180. © 2017 American Society of Civil Engineers.

Author keywords: Nonautoclaved aerated concrete; Air percent; Packing theory; Aluminum powder.

Introduction

Aerated concrete refers to concrete having a high value of pores andair voids. These air bubbles are produced to reduce the density ofthe mixture and provide good thermal insulation. Aerated concretewas first presented in the 1930s and was referred to as foamed,cellular, or gas concrete (Neville 1981; Holt and Raivio 2005;Elhaddad 1993; Ng et al. 2012).

Various uses of lightweight concrete are well known all over theworld. It is proposed that the reduction of concrete’s self-weight isthe best option to reduce the dead load of structure and eventuallyreduces the dimension of structural elements.

Aerated concrete is classified into two categories: autoclaved aer-ated concrete (AAC) and nonautoclaved aerated concrete (NAAC).Most research studies have been carried out on the autoclaved cat-egory. The aerated concrete manufacturing process involves thecreation of macroporosity in a micromortar matrix made of sand,lime, cement, and water in the presence of an expansive admixture(Cabrillac et al. 2006; Narayanan and Ramamurth 2000a). In thistype of concrete, aluminum powder reacts with the lime (releasedby the hydration of the binder) and water (Holt and Raivio 2005;Wittman 1983; Xia et al. 2013; Mostafa 2005; Cenk et al. 2010).The air voids generated by this chemical reaction cause the freshmortar to expand and lead to an increase in air pores (Narayanan andRomamurthy 2000b).

The aluminum reacts with calcium hydroxide or alkali, whichreleases hydrogen gas and forms air bubbles, as shown in Eq. (1)(PFU 1972) as follows:

3CaðOHÞ2ðaqÞðsÞ þ 2AlðsÞþ 6H2OðlÞ → 3CaO · Al2O3.6H2OðlÞ þ 3H2ðgÞ ð1Þ

Holt and Raivio (2005) confirmed that adjusting the reactionspeed and duration of the aluminum reactions is important. There-fore, it is necessary to make sure that the pore formation ends upcoinciding with the initiation of AAC hardening. Hence, the adjust-ment of aluminum powder and water content should control themacropores’ size and distribution (Boesten 2012).

Literature classifies the air pore system of aerated concrete withthe aim of studying the water transport theory as artificial air pores,intercluster pores, and interparticle pores (air pore diameters inaerated concrete are usually 0.1–1 mm).

The first general review on aerated concrete was reportedby Valore (1954a, b), Rudnai (1963), and Short and Kinniburgh(1963). Studies have shown that lightweight concrete has a greatpotential as a structural material. Furthermore, performance anddurability are other appropriate features of this concrete (Narayananand Ramamurthy 2000a; Shamsuddoha et al. 2011; Alexanderson1979; Scheffler and Paolo 2005; Esmaily and Nuranian 2012;Schwartz et al. 1998; Schapovlov 1994). In addition, Panesar(2013) proved that an increase in air pore percentage results inthe reduction of compressive strength and elastic modulus after 7and 28 days. Recent research studies also showed that in orderto create uniform pore distribution in aerated concrete, the alumi-num powder size should be enlarged. It is evident from the resultsthat the amount of aluminum particles characterizes the percentageof overlapped pores and its distribution (Liu et al. 2013). The basicissue in this study is to calculate the percentage of air in the AACor NAAC.

The usual method commonly used in ordinary concrete [ASTMC231 (ASTM 2014)] cannot accurately determine air content ofmore than 7%. Therefore, there is no study that focused on theair void content measurement in the fresh aerated concretes

1Research Assistant, School of Metallurgy and Materials Engineering,Iran Univ. of Science and Technology, P.O. Box 16765-163, Narmak,Tehran, Iran. E-mail: mohammadi.mhn@gmail.com

2Assistant Professor, School of Civil Engineering, Iran Univ. of Scienceand Technology, P.O. Box 16765-163, Narmak, Tehran, Iran (correspond-ing author). E-mail: shirzad@iust.ac.ir

3Associate Professor, School of Metallurgy and Materials Engineering,Iran Univ. of Science and Technology, P.O. Box 16765-163, Narmak,Tehran, Iran. E-mail: divandari@iust.ac.ir

Note. This manuscript was submitted on December 1, 2016; approvedon August 31, 2017; published online on December 29, 2017. Discussionperiod open until May 29, 2018; separate discussions must be submitted forindividual papers. This paper is part of the Journal of Materials in CivilEngineering, © ASCE, ISSN 0899-1561.

© ASCE 04017312-1 J. Mater. Civ. Eng.

J. Mater. Civ. Eng., 2018, 30(3): 04017312

Dow

nloa

ded

from

asc

elib

rary

.org

by

Ali

Akb

ar S

hirz

adi J

avid

on

12/2

9/17

. Cop

yrig

ht A

SCE

. For

per

sona

l use

onl

y; a

ll ri

ghts

res

erve

d.

specifically. Moreover, limited research studies have been carriedout on NAAC properties. In the present study, lightweight nonau-toclaved aerated concrete was prepared. The amount of porosity inthe concrete was changed by a variation of the aluminum powderpercentage. Subsequently, the compressive strength of mixtureswas measured and compared at time intervals of 3, 7, and 28 days.Likewise, in order to examine the workability of the prepared con-cretes, the amount of fresh concrete’s minislump was measured.Furthermore, a scanning electron microscope (SEM) was usedto analyze the type of concrete pores. Last and foremost, a novelformulaic method was proposed to determine the air percentage ofNAAC. Moreover, the effects of various aluminum powders on thefresh and hardened properties of NAAC were evaluated.

Experimental Programs

Materials

In this study, a locally made ordinary portland Type II cementaccording to the requirements of ASTM C150 (ASTM 2003)and limestone powder as filler were used. River sand with a specificgravity of 2,550 kg=m3 was also used as aggregate. The chemicaland grading properties of cement, sand, and limestone powder arepresented in Table 1 and Fig. 1, respectively. An accelerator admix-ture was also used in order to decrease the setting time of mixtures.Physical properties of accelerator admixture are presented inTable 2. The reason for using an accelerator with the proportionof 8% of the cement weight was to omit the autoclave process.An industrial oily type of aluminum powder was used in this study.

The powder is known as 1940 grade aluminum powder. As men-tioned previously, aluminum powder for aerated concrete should beflake. Hence, according to the SEM image (Fig. 2), the shape of thealuminum powder used is flake. Moreover, the size of the usedaluminum powder is in the range of 0.1–10 μm.

Mixture Proportions

The proportions of the NAAC mixtures are summarized in Table 3.As could be seen, six types of NAAC mixtures were prepared witha constant water-to-cement (W/C) ratio of 0.6 but with various per-centages of aluminum powder (Mixtures A1–A6). In order toevaluate the effect of W/C ratios, Mixtures A7–A9 were sampledwith a W/C ratio of 0.5, 0.8 and 1, respectively.

Sand content, accelerator percentage, and limestone powdercontent were constant in all the mixtures.

Table 1. Chemical Properties of Cement and Mineral Admixtures(% Mass)

Composition Sand Cement Limestone powder

SiO2 66.7 20.74 2.80Al2O3 9.8 4.90 0.35Fe2O3 5.1 3.50 0.50MgO 2.37 1.20 1.80CaO 8.8 62.95 51.22SO3 0.16 3.00 1.24Loss on ignition (%) — 1.56 42.06

Fig. 1. Particle size distribution of each solid material

Table 2. Physical Properties of Accelerator Admixture

Property Quantity or type

Physical mode PowderPH 7–8Density (g=cm3) 1.10Chloride (ppm) None

Fig. 2. SEM image of used industrial oily aluminum powder

Table 3. Mixture Proportions of NAAC Mixtures

MixCement(kg=m3)

Sand(kg=m3)

Water(kg=m3)

Limestonepowder(kg=m3) W/C

Al/C(%)

Accelerator/C(%)

A0 648 821 389 77 0.6 0.0934 0A1 648 821 389 77 0.6 0.0466 8A2 648 821 389 77 0.6 0.0934 8A3 648 821 389 77 0.6 0.1869 8A4 648 821 389 77 0.6 0.2849 8A5 648 821 389 77 0.6 0.3731 8A6 648 821 389 77 0.6 0.4673 8A7 648 821 324 77 0.5 0.0934 8A8 648 821 518 77 0.8 0.0934 8A9 648 821 648 77 1 0.0934 8

© ASCE 04017312-2 J. Mater. Civ. Eng.

J. Mater. Civ. Eng., 2018, 30(3): 04017312

Dow

nloa

ded

from

asc

elib

rary

.org

by

Ali

Akb

ar S

hirz

adi J

avid

on

12/2

9/17

. Cop

yrig

ht A

SCE

. For

per

sona

l use

onl

y; a

ll ri

ghts

res

erve

d.

Mixture Preparation

The water, limestone powder, and accelerator admixture werepoured into the mixer. The mixer was turned on and allowed tomix well for 2 min. Cement and sand were later added to the mix-ture and allowed to mix together for 4 min. Aluminum powderwas mixed separately in 100–200 g of water and then added tothe contents of the mixer. The mixing process was continued for1–2 min.

Test Procedure

Workability of NAAC Mixtures

The workability of mixtures was tested with the minislump device.The apparatus for the minislump test of NAAC mixtures consistsof a cone 60 mm high with a diameter of 70 mm at the top and100 mm at the base. The cone was placed at the center of a plateand was filled with mixture. Immediately after filling, the cone waslifted, and the average diameter (in millimeters) of spread mixtureover the table was measured.

Density and Volume Test

The density of fresh NAAC mixtures was tested according toASTM C188 (ASTM 2015). Volume change in the mixtures(due to the production of air bubbles in the mixtures) was testedat the interval of a few seconds.

Compressive Strength Test

The compressive strength of NAAC mixtures was determinedaccording to BS EN1881 (BSI 2013b) after 7 and 28 days.

Water Absorption Test

Typically, this test was carried out according to standard procedureBS 1881-Part122 (BSI 2013a); however, the difference here is thatbecause of the high porosity of the mixture, it is filled with water ina relatively short time. Hence, the test was performed at shorterintervals (1, 2, 4, and 8 min).

Measurement of Packing Density

In order to evaluate the packing density of NAAC mixtures, amethod called wet packing is applied based on literature presentedby Wong and Kwan (2008) and Ghoddousi et al. (2014). Theprocess of the measurements is described subsequently.

Table 4. Workability, Density, and Compressive Strength Results of FreshMixtures

MixDensity(kg=m3)

Minislump(cm)

7-day compressivestrength (MPa)

28-day compressivestrength (MPa)

A0 1,020 30 1.5 2.5A1 1,477 28 8.5 11.6A2 1,298 30 6 8A3 1,170 31.5 2 2.9A4 1,140 29.5 1.1 1.7A5 1,085 24.5 0.8 1.3A6 1,027 23 0.5 0.9A7 1,500 22 7.6 10.1A8 1,550 40 4.5 6.5A9 1,600 47 3.4 4.8

Fig. 3. Density and minislump results of NAAC mixtures

Fig. 4. Density and compressive strength results of NAAC mixtures

Fig. 5.Compressive strength and minislump results of NAACmixtures

© ASCE 04017312-3 J. Mater. Civ. Eng.

J. Mater. Civ. Eng., 2018, 30(3): 04017312

Dow

nloa

ded

from

asc

elib

rary

.org

by

Ali

Akb

ar S

hirz

adi J

avid

on

12/2

9/17

. Cop

yrig

ht A

SCE

. For

per

sona

l use

onl

y; a

ll ri

ghts

res

erve

d.

After making the NAAC mixture in the mixer, concrete is filledinto a mold of size 100 × 100 × 100 mm. If the NAAC mixturesinclude various materials, the volume of the solid materials (VC)in the mold could be calculated from Eq. (2) as follows:

VC ¼ Mρwuw þ ρgRg þ ρsRs þ ρcRc þ ρlRl þ ρmRm

ð2Þ

where M and V = mass and volume of NAAC, respectively; ρw =water density; uw = ratio of water volume to solid volume of granu-lar material; ρs, ρc, ρl, and ρm = densities of sand, cement, lime-stone powder, and accelerating admixture as filler, respectively; andRs, Rc, Rl, and Rm = volumetric ratios of sand, cement, limestonepowder, and accelerating admixture, respectively, to total solidmaterials. Given that the amount of aluminum powder and accel-erator admixture weight used in the mixtures are very low, they donot affect the packing density and can be ignored in the equation.

Having obtained VC and V, packing density (ϕ) may be calculatedby Eq. (3) as follows:

ϕ ¼ VC

Vð3Þ

SEM Test

The microstructure of NAAC mixtures was observed using a SEM(EVO 18, Zeiss, Oberkochen, Germany).

Results and Discussion

Workability, Density, and Compressive Strength of theFresh NAAC

The workability, density, and compressive strength results of freshmixtures are given in Table 4.

For a better understanding of the parameters listed in Table 4,they are compared in Figs. 3–5. As is evident from Fig. 3, there isan optimal aluminum percentage of 0.093 from the perspective ofminislump diameter. The results show that minislump and work-ability decrease with an increase in the amount of aluminum pow-der in comparison to optimum percentage. This could be explainedby the fact that as long as pores are separated, they are spherical andact as bearings, but when there are many pores, they join togetherand act as a network, which leads to flow-ability decrement. How-ever, the air percentage increases with an increase in the amountof aluminum powder, resulting in forming more pores and conse-quently reducing the density.

Fig. 4 shows that the increase in aluminum percentage leads toa decrease in compressive strength of the NAAC mixture. This isin agreement with the results presented by Muthu Kumar andRamamurthy (2015). It seems that the optimum percentage of alu-minum can be considered as 0.0934. By increasing the amount ofaluminum powder from 0.0934 to 0.1869, compressive strengthreduced significantly. However, increasing the percentage of alu-minum powder caused a density decrement, but with regard tocompressive strength, the optimum percentage (0.0934) would

Fig. 6. Effect of water-to-cement ratio on density and compressivestrength

Fig. 7. Artificial pores produced in the NAAC

© ASCE 04017312-4 J. Mater. Civ. Eng.

J. Mater. Civ. Eng., 2018, 30(3): 04017312

Dow

nloa

ded

from

asc

elib

rary

.org

by

Ali

Akb

ar S

hirz

adi J

avid

on

12/2

9/17

. Cop

yrig

ht A

SCE

. For

per

sona

l use

onl

y; a

ll ri

ghts

res

erve

d.

be suitable. Fig. 5 also clearly shows that there is an optimal per-centage (0.0934) from the viewpoint of suitable compressivestrength and workability.

The effect of the water-to-cement ratio on fresh and hardenedproperties of NAAC mixtures is illustrated in Fig. 6. It is obviousthat with an increase in water-to-cement ratio, compressive strengthreduced, but from the perspective of both compressive strength anddensity, an optimal W/C ratio (0.6) can be considered.

SEM Results

The porosity in aerated concrete is divided into three categories:artificial, cluster, and particle porosity. Comparing the SEM imagesof the three categories with images obtained in this study, it wasclearly found in Fig. 7 that the porosity formed in this study isan artificial porosity. When aluminum powder is very high (A6mixture), detection of the number, type, and diameter of pores isvery difficult (Fig. 8) because when the pore number increases,pores change to pore networks. This is in agreement with the resultsreported by Narayanan and Ramamurthy (2000a).

Water Absorption of Mixtures

Volumetric water absorption of NAAC mixtures at 1, 2, 4, and8 min are shown in Fig. 9. As can be seen, an increase in the amountof aluminum powder leads to more absorbed water. The reason isthat by increasing the aluminum powder, the size and relative valueof pores increase.

Packing Theory for Calculation of Air Percentage

Table 5 presents the measured packing density of A1 and A2 mix-tures at five intervals. The results show a reduction in packing den-sity with time. This might be attributed to the air bubbles produced

during the reaction of NAAC constitutions. The results also showthat with an increase in the amount of aluminum powder from0.0934 to 0.1869 (A1 to A2), packing density reduces. This is dueto a higher air percentage in the A2 mixture. Figs. 10 and 11 showthe results of volume change ratio and density with time for A1 andA2 mixtures. It can be seen that by increasing air bubbles over time,the volume increases and density reduces.

As mentioned in the Introduction, there is no study that focusedon the air void content measurement in fresh aerated concretes spe-cifically. Fig. 12 shows the measured air percentage of NAAC mix-tures A1 and A2 over time based on packing theory. It is observedthat with an increase in aluminum powder (mixture A2), the maxi-mum aerated air percentage is higher than mixture A1 containing

Fig. 8. SEM images of NAAC mixtures

Fig. 9. Water absorption of NAAC mixtures at different times

© ASCE 04017312-5 J. Mater. Civ. Eng.

J. Mater. Civ. Eng., 2018, 30(3): 04017312

Dow

nloa

ded

from

asc

elib

rary

.org

by

Ali

Akb

ar S

hirz

adi J

avid

on

12/2

9/17

. Cop

yrig

ht A

SCE

. For

per

sona

l use

onl

y; a

ll ri

ghts

res

erve

d.

less aluminum powder (21% for A2 and 16% for A1). To determinethe air percentage of NAAC having a volume change on site or in alaboratory, the following equation is obtained from Fig. 13:

y ¼ 0.2484xþ 7.1436 ð4Þ

where y = air percentage produced in the NAAC mixture; andx = percentage of final mixture volume change compared to theinitial volume.

Conclusions

The following conclusions can be drawn from the results of thisresearch:• There is an optimal percentage of aluminum (0.0934) from the

viewpoint of minislump diameter and compressive strength.After the optimum point, the increase in percentage of alumi-num results in minislump (workability and flow-ability) andcompressive strength decrement.

Table 5. Measured Packing Density of A1 and A2 Mixtures

Mix

Time (s)

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45

A1 0.549 0.536 0.536 0.536 0.524 0.524 0.513 0.506 0.502 0.482 0.474 0.472 0.467 0.463 0.458 0.454A2 0.602 0.548 0.521 0.497 0.462 0.437 0.420 0.404 0.399 0.399 0.399 0.399 0.399 0.399 0.399 0.399

Fig. 10. Results of volume change ratio and density with time for theA1 mixture

Fig. 11. Results of volume change ratio and density with time for theA2 mixture

Fig. 12.Measured air percent of NAACmixtures A1 and A2 with timebased on packing theory

Fig. 13. Relation between air percent of NAAC mixture with volumechange

© ASCE 04017312-6 J. Mater. Civ. Eng.

J. Mater. Civ. Eng., 2018, 30(3): 04017312

Dow

nloa

ded

from

asc

elib

rary

.org

by

Ali

Akb

ar S

hirz

adi J

avid

on

12/2

9/17

. Cop

yrig

ht A

SCE

. For

per

sona

l use

onl

y; a

ll ri

ghts

res

erve

d.

• Comparing the SEM images of three categories with imagesobtained in this study, it is clearly found that the porosity formedin mixtures is an artificial one.

• With an increase in aluminum content, the percentage of waterabsorbed increases. The reason is that by increasing the alumi-num powder, the size and relative value of pores increase.

• The results show that an increase in the amount of aluminumpowder reduces packing density in comparison to the mixturewith lower aluminum percentage.

• Increasing the water-to-cement ratio reduces the compressivestrength, but from the viewpoint of density, an optimal water-to-cement ratio (0.6) can be considered.

• This study proposes a newmethod of determining air percentageof aerated concrete based on packing theory. It observes that theair percentage of aerated concrete increases with an increase inaluminum powder.

Notation

The following symbols are used in this paper:M = mass;Rc = volumetric ratio of cement to total solid materials;Rl = volumetric ratio of limestone to total solid materials;Rm = volumetric ratio of accelerating admixture to total solid

materials;Rs = volumetric ratio of sand to total solid materials;uw = ratio of water volume to solid volume of granular

material;V = volume;

VC = volume of solid materials;ρc = density of cement;ρl = density of limestone;ρm = density of accelerator admixture;ρs = density of sand;ρw = density of water; andϕ = packing density.

References

Alexanderson, J. (1979). “Relations between structure and mechanicalproperties of autoclaved aerated concrete.” Cem. Concr. Compos., 9(4),507–514.

ASTM. (2003). “Standard specification for portland cement.” ASTM C150,West Conshohocken, PA.

ASTM. (2014). “Standard test method for air content of freshly mixedconcrete by the pressure method.” ASTM C231, West Conshohocken,PA.

ASTM. (2015). “Standard test method for density of hydraulic cement.”ASTM C188, West Conshohocken, PA.

Boesten, E. P. M. (2012). Influence of alternative raw materials onautoclaved aerated concrete, Eindhoven Univ. of Technology,Eindhoven, Netherlands.

BSI (British Standards Institution). (2013a). “Method for determination ofwater absorption.” BS EN1881 Part 122, London.

BSI (British Standards Institution). (2013b). “Standard test method forcompressive strength of cubic concrete specimens.” BS EN Standard1881: Part 116, London.

Cabrillac, R., Fiorio, B., Beaucour, A., Dumontet, H., and Ortola, S. (2006).“Experimental study of the mechanical anisotropy of aerated concretes

and of the adjustment parameters of the introduced porosity.” Constr.Build. Mater., 20(5), 286–295.

Cenk, K., Haldun, K., and Bekir, T. I. (2010). “Utilization of natural zeolitein aerated concrete production.” Cem. Concr. Compos., 32(1), 1–8.

Elhaddad, M. H. (1993). Improvements of concrete properties to resistlocal climatic condition in the state of Qatar: Research project, QatarUniv., Doha, Qatar.

Esmaily, H., and Nuranian, H. (2012). “Non-autoclaved high strengthcellular concrete from alkali activated slag.” Constr. Build. Mater.,26(1), 200–206.

Ghoddousi, P., ShirzadiJavid, A. A., and Sobhani, J. (2014). “Effectsof particle packing density on the stability and rheologyof self-consolidating concrete containing mineral admixtures.” Constr. Build.Mater., 53, 102–109.

Holt, E., and Raivio, P. (2005). “Use of gasification residues in aeratedautoclaved concrete.” Cem. Concr. Res., 35(4), 796–802.

Liu, H., Bu, Y., and Guo, S. (2013). “Improvement of aluminum powderapplication measure based on influence of gas hole on strength proper-ties of oil well cement.” Constr. Build. Mater., 47, 480–488.

Mostafa, N. Y. (2005). “Influence of air-cooled slag on physicochemicalproperties of autoclaved aerated concrete.” Cem. Concr. Res., 35(7),1349–1357.

Muthu Kumar, E., and Ramamurthy, K. (2015). “Effect of fineness anddosage of aluminium powder on the properties of moist-cured aeratedconcrete.” Constr. Build. Mater., 95, 486–496.

Narayanan, N., and Ramamurthy, K. (2000a). “Microstructural investiga-tions on aerated concrete.” Cem. Concr. Res., 30(3), 457–464.

Narayanan, N., and Ramamurthy, K. (2000b). “Structure and properties ofaerated concrete: A review.” Cem. Concr. Compos., 22(5), 321–329.

Neville, A. M. (1981). Properties of concrete, Pitman Books, London.Ng, S. C., Low, K. S., and Tioh, N. H. (2012). “Potential use of clayey soil

in aerated lightweight concrete.” KSCE J. Civ. Eng., 16(5), 809–815.Panesar, D. K. (2013). “Cellular concrete properties and the effect of

synthetic and protein foaming agents.” Constr. Build. Mater., 44,575–584.

PFU Utilization. (1972). Central electricity generating board, Gibbons,Wolverhampton, U.K.

Rudnai, G. (1963). Light weight concretes, AkademiKiado, Budapest,Hungary.

Schapovlov, V. I. (1994). “Porous metal.” MRS Bull., 19(4), 24–28.Scheffler, M., and Paolo, C. (2005). Cellular ceramics structure, manufac-

turing, properties and applications, Wiley-VCH,Mörlenbach, Germany.Schwartz, D. S., Shih, D. S., Evans, A. G., and Wadley, H. N. G. (1998).

“Porous and cellular materials for structural applications.” Proc.,Materials Research Society Symp., Materials Research Society,Warrendale, PA, 521.

Shamsuddoha, M., Islam, M. M., and Noor, M. A. (2011). “Feasibility ofproducing lightweight concrete using indigenous materials withoutautoclaving.” MIST J., 3, 1–9.

Short, A., and Kinniburgh, W. (1963). Light weight concretes, C.R. BooksLtd., London.

Valore, R. C. (1954a). “Cellular concretes-composition and methods ofpreparation.” J. Am. Concr. Inst., 25, 773–795.

Valore, R. C. (1954b). “Cellular concretes-physical properties.” J. Am.Concr. Inst., 25, 817–836.

Wittman, F. H. (1983). Autoclaved aerated concrete, moisture andproperties, development in civil engineering, Elsevier, Amsterdam,Netherlands.

Wong, H. H. C., and Kwan, A. K. H. (2008). “Packing density of cementi-tious materials. I: Measurement using a wet packing method.” Mater.Struct., 41(4), 689–701.

Xia, Y., Yan, Y., and Hu, Z. (2013). “Utilization of circulating fluidized bedfly ash in preparing non-autoclaved aerated concrete production.”Constr. Build. Mater., 47, 1461–1467.

© ASCE 04017312-7 J. Mater. Civ. Eng.

J. Mater. Civ. Eng., 2018, 30(3): 04017312

Dow

nloa

ded

from

asc

elib

rary

.org

by

Ali

Akb

ar S

hirz

adi J

avid

on

12/2

9/17

. Cop

yrig

ht A

SCE

. For

per

sona

l use

onl

y; a

ll ri

ghts

res

erve

d.