Preliminary views on the potential of foamed concrete as a structural material
TL;DR: In this paper, a laboratory study of the development of foamed concrete, utilising two types of fly ash, with the potential for use in structural applications, was described, where fine fly ash (i.e. to BS EN 450) was used to partially replace Portland cement and coarse fly ash to replace sand fine aggregate.
Abstract: Low self-weight (800 to 1600 kg/m3), high workability (flowing and self-compacting) and excellent thermal insulating properties ( 25 N/mm2). This paper describes a laboratory study of the development of foamed concrete, utilising two types of fly ash, with the potential for use in structural applications. ‘Fine’ fly ash (i.e. to BS EN 450) was used to partially replace Portland cement and a ‘coarse’ fly ash (i.e. to BS 3892-2) to replace sand fine aggregate. In addition, the potential of polypropylene fibres in foamed concrete to enhance plasticity and tensile strength was examined. The key early age, engineering and durability properties were meas...
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TL;DR: In this article, the authors classify literature on foam concrete in terms of constituent materials (foaming agent, cement and other fillers used), mix proportioning, production methods, fresh and hardened properties of foam concrete.
Abstract: Though foam concrete was initially envisaged as a void filling and insulation material, there have been renewed interest in its structural characteristics in view of its lighter weight, savings in material and potential for large scale utilization of wastes like fly ash. The focus of this paper is to classify literature on foam concrete in terms of constituent materials (foaming agent, cement and other fillers used), mix proportioning, production methods, fresh and hardened properties of foam concrete. Based on the review, the following research needs have been identified: (i) developing affordable foaming agent and foam generator, (ii) investigation on compatibility between foaming agent and chemical admixtures, use of lightweight coarse aggregate and reinforcement including fibers, (iii) durability studies, and (iv) factors influencing foam concrete production viz., mixing, transporting and pumping.
753 citations
TL;DR: In this article, the authors address some of the sustainability questions currently facing the cement and concrete industry, in the context of the utilisation of foam concretes based either on ordinary Portland cement (OPC) or on geopolymer binders.
567 citations
TL;DR: Foamed concrete possesses characteristics such as high strength-to-weight ratio and low density as discussed by the authors, which reduces dead loads on the structure and foundation, contributes to energy conservation, and lowers the labor cost during construction.
562 citations
TL;DR: In this paper, the thermal conductivity of oil palm shell foamed geopolymer concrete (OPSFGC) was investigated and compared with conventional wall materials, such as block and brick.
295 citations
TL;DR: In this paper, the contribution of expanded polystyrene (EPS) particles on fire resistance, thermal conductivity and compressive strength of foamed concrete has been investigated for densities ranging from 1200 to 150 kg/m3 with an EPS volume range of 0 −82.22% and water-cement ratio of 0.33.
267 citations
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TL;DR: In this paper, the authors investigated the validity and accuracy of these alternate relations and found that the splitting tensile strength is not proportional to the 0.5 power of compressive strength, and proposed a 0.69 power relation as an alternative to the ACI 318 relation.
Abstract: The 0.5 power relation adopted by ACI Committee 318 predicting the splitting tensile strength of concrete from its compressive strength has been investigated. Research has consistently indicated that the relation in the Building Code Requirement does not agree particularly well with test results. Consequently, researchers have proposed alternative relations. The research for this paper investigated the validity and accuracy of these alternate relations. Tensile strength preditions from these relations were compared with test results assembled from various sources. It was found that the splitting tensile strength is not proportional to the 0.5 power of compressive strength. Although most of the alternate relations appear to be good, the assembled test data revealed that 0.69 is the most accurate power relation. Thus 0.69 power relation is proposed as an alternative to the ACI 318 relation.
146 citations
01 Jan 2003
TL;DR: In this paper, the benefits of low-lime fly ash to both normal weight and lightweight foamed concrete have been discussed, and it is shown that fly ash can be used to partially or fully replace the fine aggregate, if used in a carefully balanced way.
Abstract: This paper addresses some of the issues that have long been problematic to the fly ash industry, ie why is utilisation far less than production and, given the quantities involved, how can large volume use in concrete be maintained without the significant on-costs of processing and beneficiation. The paper does not claim to provide all the answers, indeed after half a century of large scale use there are not likely to be any quick fixes, but instead reviews the benefits that unprocessed, conditioned, run-of station, low-lime fly ash can bring to both normal weight and lightweight foamed concrete. The approach followed attempts to demonstrate that this type of fly ash can be used to partially or fully replace the fine aggregate, if used in a carefully balanced way. Perhaps more importantly, concrete producers can stockpile and use existing equipment to handle this ash similarly to sand. This overcomes issues of investment in specialised handling and storage bins, which often deters smaller companies. It is shown that, used in this way, the heat evolved and strength can be enhanced and the use of primary aggregate reduced. However, the results show that the direct substitution of coarse fly ash for sand can reduce workability of normal weight concrete and increase drying shrinkage strain in foamed concrete and care has to be taken to address these issues, where they can adversely affect the quality of concrete in a particular application.
46 citations