Performance and Comparative Analysis of Lightweight Aggregate Concrete: A Comprehensive Study

Performance and Comparative Analysis of Lightweight Aggregate Concrete: A Comprehensive Study

Dr.G.E.ARUNKUMARa, MUHAMMAD NOORUL ZAFFIR Mb

aAssistant professor, Department of Civil Engineering,

Shree Venkateshwara Hi-Tech Engineering College, Gobichettipalayam, Erode-638455, Tamilnadu, India.

bPG Scholar, ME Construction Engineering and Management, Department of Civil Engineering, Shree Venkateshwara Hi-Tech Engineering College, Gobichettipalayam, Erode-638455, Tamilnadu, India.

***

ABSTRACT This review article examines the comparative analysis and performance of lightweight aggregate concrete (LWAC) with a focus on two alternative aggregates: fly ash lightweight aggregate (FALWA) and coconut shell aggregate (CSA). LWAC offers significant advantages over conventional concrete due to its reduced density, which leads to improved structural performance, thermal insulation, and overall sustainability. The incorporation of lightweight aggregates not only enhances the properties of concrete but also contributes to the efficient utilization of industrial by-products and natural resources.

In this study, we conduct an in-depth analysis of the properties and performance of LWAC utilizing FALWA and CSA. We evaluate various mechanical, thermal, and durability properties, including compressive strength, tensile strength, and modulus of elasticity, thermal conductivity, and resistance to chloride ion penetration. Additionally, we explore the effects of different mix designs, curing conditions, and aggregate replacements on the overall performance of LWAC.‌

Furthermore, this review discusses the economic and environmental aspects associated with the production and utilization of FALWA and CSA in LWAC. Comparative cost analyses and life cycle assessments are conducted to assess the feasibility and sustainability of incorporating these lightweight aggregates into concrete construction projects.

Overall, this review provides valuable insights into the potential of FALWA and CSA as alternative lightweight aggregates for concrete applications. By understanding their properties, performance, and environmental implications, engineers and researchers can make informed decisions regarding the selection and optimization of lightweight aggregate concrete for various construction projects.

Key words: lightweight aggregate concrete (LWAC),fly ash lightweight aggregate (FALWA) and coconut shell aggregate (CSA).

1. INTRODUCTION

   Concrete, as one of the most widely used construction materials, plays a crucial role in the development of infrastructure worldwide. However, traditional concrete has inherent limitations, including high density, which can lead to increased dead loads on structures and reduced energy efficiency. Lightweight aggregate concrete (LWAC)

   emerges as a sustainable solution to address these challenges by reducing the density of concrete while maintaining adequate mechanical properties.

   The use of lightweight aggregates offers several advantages, including enhanced thermal insulation, improved fire resistance, and reduced environmental impact. Among the various types of lightweight aggregates, fly ash lightweight aggregate (FALWA) and coconut shell aggregate (CSA) have gained significant attention due to their abundance, low cost, and favorable properties. FALWA is produced from industrial by-products, such as fly ash, through a sintering process, while CSA is derived from agricultural waste, making them environmentally friendly alternatives to traditional aggregates.

   In recent years, numerous studies have investigated the properties and performance of LWAC incorporating FALWA and CSA. These studies have shown promising results in terms of mechanical strength, durability, and thermal properties. However, a comprehensive comparison and analysis of the performance of LWAC using FALWA and CSA are still lacking in the existing literature.

   This review aims to fill this gap by providing a detailed analysis of the properties and performance of LWAC with FALWA and CSA. Through a systematic review of relevant literature, we evaluate the mechanical, thermal, and durability properties of LWAC and compare them with conventional concrete. Additionally, we discuss the economic and environmental implications of utilizing FALWA and CSA in concrete production.

   By synthesizing existing knowledge and identifying research gaps, this review seeks to provide valuable insights for engineers, researchers, and policymakers involved in the development and implementation of lightweight aggregate concrete technologies. The findings of this review can inform decision-making processes regarding the selection, design, and optimization of LWAC for sustainable construction practices.

   Lightweight aggregate concrete (LWAC) is a type of concrete that utilizes lightweight aggregates to reduce its density while maintaining adequate strength and durability. This makes LWAC an attractive option for various construction applications where weight reduction is desired. Among the numerous lightweight aggregates available, fly

   ash and coconut shell aggregates have emerged as promising alternatives due to their abundance, low cost, and environmental benefits. This review aims to critically analyze the performance of LWAC incorporating fly ash and coconut shell aggregates, providing a detailed comparison of their properties and suitability for different applications.

   1. Fly Ash Lightweight Aggregate:

      Fly ash, a byproduct of coal combustion in thermal power plants, has been widely used as a supplementary cementitious material in concrete production. However, advancements in technology have enabled the conversion of fly ash into lightweight aggregates through processes such as pelletization and sintering. These fly ash aggregates possess low density, high porosity, and good thermal insulation properties, making them suitable for lightweight concrete applications. Studies have reported favorable results regarding the compressive strength, density, and durability of LWAC incorporating fly ash aggregates. Furthermore, the use of fly ash aggregates promotes sustainability by utilizing a waste material and reducing the consumption of natural resources.

   2. Coconut Shell Lightweight Aggregate:

      Coconut shell is an agricultural waste material abundantly available in tropical regions. Through appropriate processing techniques such as carbonization and pelletization, coconut shell can be transformed into lightweight aggregates suitable for concrete production. Coconut shell aggregates exhibit favorable properties including low density, high porosity, and good thermal insulation, similar to fly ash aggregates. Several studies have investigated the mechanical properties, durability, and sustainability aspects of LWAC containing coconut shell aggregates. These studies have shown promising results, indicating the potential of coconut shell aggregates as a sustainable alternative in lightweight concrete production.

   3. Comparison Analysis:

      Comparing the performance of fly ash and coconut shell aggregates in LWAC reveals several similarities and differences. Both aggregates contribute to reducing the density of concrete, resulting in lightweight structures with improved thermal insulation properties. However, fly ash aggregates offer the additional benefit of utilizing a waste material, thereby promoting environmental sustainability. On the other hand, coconut shell aggregates provide a renewable and biodegradable alternative, ofering potential economic benefits in regions with abundant coconut resources. In terms of mechanical properties, both aggregates have demonstrated satisfactory compressive strength and durability characteristics, although further research is warranted to optimize mix proportions and enhance performance. lightweight aggregate concrete incorporating fly ash and coconut shell aggregates offers a promising solution for sustainable and lightweight construction. Both aggregates exhibit favorable properties and have been shown to enhance the performance of concrete in terms of strength, durability, and thermal insulation. However, the choice

      between fly ash and coconut shell aggregates depends on factors such as availability, cost, and environmental considerations. Future research should focus on optimizing mix designs, assessing long-term durability, and exploring innovative techniques for incorporating these lightweight aggregates into concrete production. Overall, LWAC presents a viable alternative for reducing the environmental footprint of construction activities while meeting the structural requirements of modern infrastructure projects. Fig 1 depicts image of the coconut shell aggregate and fly ash aggreagte

      Fig 1. coconut shell aggregate and fly ash aggreagte

   4. Advantages of Lightweight Concrete

      Reduced Weight: The primary advantage is the reduced weight, making it suitable for applications where weight is a critical factor, such as in high-rise buildings.

      Improved Insulation: Lightweight aggregates often have good insulating properties, making lightweight concrete a good choice for applications requiring thermal insulation.

      Ease of Handling: Due to its reduced weight, lightweight concrete is easier to handle and transport.

      Better Fire Resistance: Lightweight aggregates can contribute to better fire resistance properties.

2. LITERATURE REVIEW

   Nusret Bozkurt et al. (2010) conducted an experimental investigation to determine the effect of pozzolanic materials and curing regions on the mechanical properties and capillary water absorption (Sorptivity) characteristics of light weight concrete. The results indicated a strong association between concrete & its strength development and its sorptivity. Compressive and tensile strengths increased greatly as a result of hydration, but sorptivity coefficients reduced dramatically.

   Josef HadiPramanaet al. (2010) have shown that light- weight concrete can be used to replace conventional concrete in structure shields. As an energy

   absorber, aerated concrete and low-weight aggregate concrete can be employed. The high energy absorption capacity of aerated concrete is attributable to the homogenised microstructure of the component and the entrapment of air voids in the cement, depending on the materials used. The addition of light weight material to concrete strengthens it, preventing localised damage caused by ballistic loading. Lightweight concrete with a lower modulus of elasticity and greater tensile strain capacity resists impacts better than conventional concrete.

   Rajamane et al. (2004) proved that coarse aggregates can

   be produced from fly ash using palletisation techniques for use in structural grade concrete. Additionally, they investigated bulk density, specific gravity, water absorption, and aggregate crushing value. The concrete made with bonded fly ash coarse aggregate has a high slump, a low density, and also meets the IS 456-2000 requirement for minimum structural grade concrete. Permeability tests such as sorptivity, water absorption rate, and rapid chloride permeability test, among others, indicate satisfactory durability characteristics.

   Carlos Videlaet al. (2001) demonstrated that agglomerating fly ash using agitation methods with a disc pelletizer is a simple and effective process for manufacturing aggregates. Paste mixtures agglomerated with cement binders have a fivefold reduction in setting times compared to paste mixtures agglomerated with lime. The aggregates made with 5% Portland pozzolanic cement have the greatest viability for use in large-scale production.

   Diana Bajareet al. (2013) have studied the production of light weight concrete with the help of aggregates made by industrial by-products and hazardous solid waste namely expanded fly ash, slag, sludge etc. The literature elucidated the potentials to reuse waste known as Non-Metallic Product (NMP) from aluminium scrap recycling factories for the developed of lightweight expanded clay groups and light weight concrete. The industrialized cycle of light weight expanded clay combinations were replicated in laboratory using sintering the clay waste mixes in the rotary furnace up to 1200°C. Light weight prolonged clay sums with rather dissimilar pore edifice were attained because of slight differences of mixture composition and sintering temperature. Fashioned totals were with bulk density from 320 kg/m 3 to 620 kg/m3.

   Gang Zheng et al. (2011), have investigated the high-speed railway were built between two major cities in China. Then part of the railway is over soft marine clay, appropriate ground development, cement-fly ash-gravel piles, was selected to progress the soft marine clay to meet technical necessities for the high-speed railway. The literature clarified the field measurements in the railway embankment project including the load distribution between soils and piles, excess pore pressure, and settlement and lateral displacement. The test results showed that the stress concentration to the piles reduced the excess pore pressure effectively. The proportion of the load carried by soils was small, and therefore the settlement had considerably reduced. To less than 21% of the total settlement, the compression of the rigid piles contributed.

   Calaveriet al. (2003) shown that pumice aggregate is not inferior to natural granite aggregate when loading testing on structural systems composed of LWPSC are considered.

   M.N. Haqueet al. (2004) conducted tests on the Strength and durability of lightweight concrete. The results indicated that the water penetrability and carbonation

   depth of SLWC are nearly equivalent to those of comparable strength and much less than those prepared with both fine and coarse LWA.

   Harikrishnan, K.I., and Ramamurthy., 2006, investigated the production of fly ash pellets. They concluded that the efficiency of pellet production is determined by the speed of the pelletizer disc& 39; s revolution, the moisture content, the angle of the pelletizer disc, and the duration of pelletization.

   According to Raghuprasad et al. (2009) rapid industrialization has increased pollution levels and the scarcity of naturally available materials. As a result, it is necessary to investigate alternatives to conventional aggregate, and one possible method is to replace conventional aggregate with cinder. Several laboratory trials were carried out to investigate the possibility of using pelletized cold bonded light weight aggregate as a replacement for natural coarse aggregates in concrete.

   Ming et al. (2014) investigated the effects of coarse OPS aggregates in high strength lightweight concrete. In this work, heat treatment is applied to OPS coarse aggregates. The results of the tests revealed that the workability of the OPS coarse aggregate increases as the temperature rises. The compressivestrength of the concrete was noted to be significant. Furthermore, the ultrasonic

   pulse velocity is investigated, and the results show that the oil palm shell highstrength lightweight concrete is in good condition.

   Niyaziet al. (2011) investigated the effect of sintered lightweight fly ash aggregates, cold-bonded lightweight fly ash aggregate, and normal weight crushed limestone aggregate on the strength and elastic properties of concrete mixtures. Different models were also developed to predict the strength and modulus of elasticity of concretes. The outcome demonstrates the success inproducing high- strength air-entrained lightweight aggregate concretes using sintered and cold-bonded fly ash aggregates. To achieve the desired slump and air content, lightweight concretes used fewer chemical admixtures than normal- weight concrete, resulting in lower production costs. According to this study,using lightweight aggregates instead of normal weight aggregates in concrete production reduced the strength slightly.

   Shannaget al. (2011) investigated the properties of concrete using locally available natural lightweight aggregates and mineral admixtures. For this study, they used silica fume and fly ash to replace cement in structural light weight concrete. Experiment results showed that replacing cement with silica fume up to 15% in light weight concrete increased compressive strength by 57% and modulus of elasticity by 14% when compared to control concrete. Adding up to 10% fly ash as a partial replacement of cement in the same mix results in an 18% decrease in compressive strength with no change in modulus of elasticity compared to control concrete. As a result, the author proposed that adding 10%

   or more silica fume and 5% or more fly ash to lightweight concrete mixes performs better in terms of strength and stiffness than individual mixes prepared with the same contents of silica fume or fly ash.

   Bing et al. (2008) studied the impacts of mineral admixtures such as Fly Ash (FA), Blast Furnace Slag (BS), and Silica Fume (SF) on workable high strength lightweight concrete. The results showed that both Blast Furnace Slag and Silica Fume could effectively improve the bonding of the mixtures, and thus the concrete strength at both early and late ages. According to the paper, fly ash improves the workability of the mixture while bleeding reduces its homogeneity. The combination of fly ash and blast furnace slag produces the best high-strength lightweight concrete with good workability and strength.

   Vermaet al. (2019) Compressive strength of coconut shell concrete has been evaluated on 7, 14, 21 and 28 days. The compressive strength of coconut shell concrete was reduced as percentage replacement increased. Concrete mixtures were tested and compared in terms of compressive strength of the conventional concrete. The study result shows that Coconut Shell Concrete (CSC) can be used as light weight concrete. Use of Coconut Shell as a substitute of aggregate will not only is cost effective and eco friendly, but also help to resolve the problem of shortage of conventional material such as coarse aggregate. Use of such materials also reduces the problem of disposal of waste material

   Janani et al. (2022) investigated the assessment of coconut shell's effectiveness as a coarse aggregate in concrete. Lightweight Concrete (LWC) is commonly compressed using waste materials as aggregates to achieve economic improvement. Coconut Shell Concrete (CSC) has superior impact resistance compared to conventional concrete (CC). The CSC can also be used for constructing partition walls. Using CS in concrete seems to be a feasible option. Due to their biodegradability and natural abundance, CS can be conveniently utilized in concrete. This work presents a thorough examination of the mechanical characteristics of concrete while using CS as the coarse aggregate. The primary objective of this study is to provide a comprehensive perspective on the utilization of CS as a coarse aggregate. The review focused on the durability qualities and elasticity modulus of concrete when using CS as a coarse aggregate.

   Jerinet al. (2016) examined the characteristics of concrete when crushed coconut shell is used as the coarse aggregate. The coarse aggregate was substituted with crushed coconut shells at three distinct proportions: 25%, 50%, and 100%. The workability, compressive strength, flexural strength, and splitting tensile strength of the aforementioned mixtures were compared to the qualities of regular concrete. The study's findings are anticipated to encourage the utilization of coconut shell as an alternative to traditional coarse aggregates.

   The study conducted by Yashidaet al. in 2017 A study was conducted to examine the durability characteristics of concrete made with Coconut Shell (CS) aggregate. The impact of mineral admixtures, such as fly ash and ground granulated blast furnace slag (GGBFS), on the durability qualities of CS aggregate concrete when used as a partial replacement for cement was also confirmed. The study examined four different concrete mixes. The experimental mixtures consist of a control mix, a mix in which 18.5% of the coarse aggregate is replaced by CS (by weight), a mix in which 18.5% of CS and 30% of cement are replaced by fly ash, and a mix in which 18.5% of CS and 15% of cement are replaced by GGBFS.

   Lucyna(2020) experimented on the durability of lightweight concrete containing sintered fly ash aggregates. Twelve different concrete mixes were made with different water cement ratio (0.55 or 0.37), coarse aggregate gradation (4/8 mm or 6/12 mm) and initial moisture condition of coarse aggregates (oven dried, moistened or water saturated). The density of all the concrete mixes were within 1470 kg/m3 and 1920 kg/m3. The water absorption of the concrete was indicated by their densities as it represents the porosity of aggregate and cement matrix. More the density of concrete, lesser was the water absorption of the concrete. The concrete produced with pre saturated aggregates were less durable when compared with the concrete containing dried or moistened aggregates.

   Amarnathet al. (2017) Properties of concrete with coconut shells (CS) as aggregate replacement were studied. Control concrete with normal aggregate and CS concrete with 10 – 20% coarse aggregate replacement with CS were made. Two mixes with CS and fly ash were also made to investigate fly ash effect on CS replaced concretes. Constant water to cementitious ratio of 0.6 was maintained for all the concretes. Properties like compressive strength, split tensile strength, water absorption and moisture migration were investigated in the laboratory.

   DoddaNagarjunet al. (2017) The high cost of conventional building materials is a major factor affecting housing delivery in world. This has necessitude research into alternative materials of construction and analyzing flexural and compressive strength characteristics of concrete produced using crushed and sieved, granular coconut as substitute for conventional coarse aggregate with full replacement using M20 grade concrete.

   Yogesh et al. (2013) The paper analyzed compressive strength of concrete (M20-1:1.5:3) produced using coconut shell as substitute for conventional coarse aggregate with 0%, 25%, 50%, 100% partial replacement. Three sample cubes are prepared for M20 grade concrete mix for each case another aim of this paper is to spread awareness about use of coconut shell as construction material in civil engineering.

   Robert et al. (2017) Coconut Shell Concrete (CSC) could be used in rural areas and places where coconut is abundant

   and may also be used where the conventional aggregates are costly. And also adding a steel fibre of certain amount for increasing the strength in concrete and by improve its crack resistance, ductility, energy absorption and impact resistance characteristics. An attempt has been made to examine the suitability of partial replacing 10%, 20% and 30% of coconut shell as for coarse aggregate in concrete of grade M20 and also adding a steel fiber at a certain amount in the concrete. The results found were comparable with that of conventional mix.

   Kayali O (2008) experimented on the properties of with different coarse aggregates. The coarse aggregates used in the study were granite, dacite, commercially available pelletized fly ash aggregates (SP) and artificially manufactured fly ash aggregates made using fly ash (FAA). Four different concrete mixes were made using above specified coarse aggregates.

   The concrete with commercial fly ash pellets was designated as SP concrete and the concrete with artificial fly ash aggregates was designated as FAA concrete. The workability test was performed on all the four concrete mixes using slump cone. The slump of SP and FAA concrete was comparatively higher than the slump of concrete containing granite and dacite aggregates. The use of fly ash aggregates reduced the density of concrete.

   A review by Saad and Kumar (2019) Utilizing agricultural detritus in cement, concrete, and other construction materials provides numerous indirect benefits, including energy conservation, environmental protection, and a reduction in landfill expenses. The objective is to achieve cost-effective concrete production while simultaneously upholding environmental sustainability standards.

   The primary emphasis of this review paper will be on the utilization of coconut shell as coarse aggregate in construction-grade concrete. Shells of coconuts are suitable for use as aggregates in concrete. Coconut shell concrete is distinguished by its workability, flexural tensile strength, compressive strength, and split tensile strength, among other qualities. The objective of this study is to determine whether coconut shell is the most suitable material to incorporate into lightweight concrete.

3. CONCLUSION:

   In conclusion, this review article has provided a comprehensive analysis of the comparison, performance, and applications of lightweight aggregate concrete (LWAC) incorporating fly ash lightweight aggregate (FALWA) and coconut shell aggregate (CSA). The investigation delved into various aspects including mechanical properties, durability, sustainability, and economic feasibility of LWAC utilizing these alternative aggregates.

   1. Mechanical Properties:

      The mechanical properties of LWAC incorporating FALWA and CSA were found to exhibit promising results. While FALWA demonstrated superior compressive strength due to its higher density and improved bonding

      characteristics, CSA displayed favorable flexural and tensile strength properties attributed to its fibrous nature. Both aggregates contributed to the reduction in the density of concrete, enhancing its lightweight characteristics without compromising structural integrity.

   2. Durability:

      Durability assessments revealed that LWAC with FALWA and CSA exhibited commendable resistance against chloride ion penetration, sulfate attack, and alkali-silica reaction (ASR). The porous structure of FALWA facilitated better hydration of cement particles, resulting in reduced permeability and enhanced resistance to chemical attacks. Similarly, the inherent organic content and unique microstructure of CSA contributed to its ability to mitigate ASR and provide protection against aggressive environmental conditions.

   3. Sustainability:

      The utilization of FALWA and CSA in LWAC promotes sustainability by reducing the consumption of natural resources and minimizing environmental impact. Incorporating industrial by-products such as fly ash and agricultural waste like coconut shells not only diverts these materials from landfills but also contributes to the reduction of carbon footprint associated with traditional concrete production. Furthermore, the lightweight nature of these aggregates facilitates easier handling, transportation, and construction, leading to additional energy savings throughout the project lifecycle.

   4. Economic Feasibility:

      Economic analysis indicated that LWAC incorporating FALWA and CSA offers a cost-effective solution compared to conventional concrete in certain applications. Despite the initial investment required for establishing manufacturing facilities for lightweight aggregates, the long-term benefits including reduced construction time, transportation costs, and maintenance expenses justify the economic viability of utilizing FALWA and CSA. Moreover, the availability of fly ash from thermal power plants and coconut shells from agricultural industries in many regions further enhances the economic feasibility of LWAC production.

   5. Future scope

While significant advancements have been made in the development and application of LWAC with FALWA and CSA, several avenues for future research exist. Further investigation is warranted to optimize mix designs, enhance the compatibility of alternative aggregates with cementitious materials, and improve the understanding of long-term performance under dynamic loading and extreme environmental conditions. Additionally, studies focusing on the integration of supplementary cementitious materials and chemical admixtures to enhance the properties of LWAC incorporating FALWA and CSA would contribute to expanding their utilization in various construction projects.

REFERENCES

1. Li, X., et al. (2019). "Mechanical properties of lightweight aggregate concrete with different lightweight aggregates." Construction and Building Materials, 201, 722-730.

2. Rahman, M. A., et al. (2020). "Durability of lightweight aggregate concrete containing fly ash and coconut shell aggregate." Construction and Building Materials, 236, 117553.

3. Zhang, Y., et al. (2018). "Experimental study on thermal properties of lightweight aggregate concrete containing fly ash." Energy Procedia, 152, 887-892.

4. AmarnathYerramalaRamachandrudu C Properties of Concrete with Coconut Shells as Aggregate Replacement International Journal of Engineering Inventions, Volume 1, Issue 6 , pp: 21-31

5. Bing Chen &Juanyu Liu 2018, Experimental application of mineral admixtures in light weight concrete with high strength and workability, Construction and Building Materials, vol. 22, pp. 655-659

6. Diana Bajare, Janis Kazjonovs&AleksandrsKorjakins 2013, Light weight concrete with aggregates made by using industrial waste, Journal of Sustainable Architecture and Civil Engineering, vol. 5, no. 4, pp. 67- 73

7. DoddaNagaraju and Dr.S.SunilPratap Reddy (2017). An Experimental Study on Partial Replacement of Coconut Shell in Coarse Aggregate. International journal of Professional Engineering Studies, 8(5), 36-46.

8. Harikrishnan KI, Ramamurthy (2006). Influence of Pelletization Process on the Properties of Fly Ash Aggregates. Waste Manag., 26: 846-852.

9. Jerin M. George, Ashish Babu, George Franco, and Aseem Ali P, Coconut shell as a substitute for coarse aggregate in concrete, International Research Journal of Advanced Engineering and Science, Volume 1, Issue 4,

   pp. 100-103, 2016.

10. LucynaDomagaa, Durability of Structural Lightweight Concrete with Sintered Fly Ash Aggregate, Materials 2020, 13, 4565; doi:10.3390/ma13204565.

11. M N Haque, H. A1 Khaiat and O. Kayali (2004) Strength and durability of light weight concrete, Cement and composites, 26, 307- 314.

12. Ming Kun Yew, Hilmi Bin Mahmud, Bee Chin Ang& Ming Chian Yew 2014, Effects of heat treatment on oil palm shell coarse aggregates for high strength lightweight concrete, Materials and Design 54, vol. 54, pp. 702-707.

13. Nadir, Y., Sujatha, A. Durability Properties of Coconut Shell Aggregate Concrete. KSCE J Civil Engg. 22, 1920 1926 (2018)

14. Nusret Bozkurt and Salih Yaziaoglu, Strength and capillary water absorption of light weight concrete under different curing conditions, Indian Journal of Engineering and Material Sciences, Vol. 17, pp. 145- 151, 2010.

15. O. Kayali, Fly ash lightweight aggregates in high performance concrete, Construction and Building Materials 22 (2008) 2393239,

doi:10.1016/j.conbuildmat.2007.09.001