The Influence of Superplasticisers on the Fresh and Mechanical Behaviour of Foam Concrete Utilizing Pofa as Sand Replacement

Abstract

Since the foam concrete is delicate, it is important to carefully choose the additives, such as superplasticiser (SP), to be used in this type of concrete. The effect of using different types and percentages of SP on the performance of foam concrete with target density of 1500±50 kg/m3 has been investigated in this study. A sustainable material, Palm Oil fuel ash (POFA), used as a sand replacement at a level of 20% by weight. Five types of SP have been used in this study, including Sulphonated polymer-based, selected synthetic and organic polymers-based and three Polycarboxylate ether-based (PCE). Different SP contents (0.0%, 1.0% and 2.0%) have been used as a ratio of cement weight. Workability, consistency, foam stability and mechanical properties were investigated. The results showed that types and quantity of SP have a significant effect on the different properties of the foam concrete. Workability, compression strength and tension strength improved remarkably for most specimens. The use of 2% SP4, a PCE SP, showed superior workability, compression strength and tensile strength with acceptable stability.

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“…All samples compressive capacities grew with aging. Additionally, using SP significantly raises the compressive strength of foamed concrete [49]. Age-related increases in compression resistance may be detected for all specimens.…”

“…2-5). The values obtained by Al-Shwaiter and Awang [49] concerning the compression, flexure and tension of foamed concrete samples with various forms of SP are given in Table 4. [49].…”

“…The SP4-2 sample (2% SP) had the highest flexural strength, exhibiting an increase of 21.5% compared with the reference. Interesting to note is that when using the same SP at a ratio of 1.0%, the flexural strength decreased by 21% compared with the reference [49].…”

“…Al-Shwaiter and Awang [49] used a vertical shaft mixer. After mixing the cement, sand, POFA, and water, the appropriate type and quantity of SP is added to the ready mixed concrete.…”

“…Fresh foam concrete density was kept at about 1630 kg/m 3 , to maintain the hardened concrete foam density within the desired range of 1500±50 kg/m 3 . To minimize the moisture loss, the specimens were covered with a plastic sheet for 24 hours after casting [49].…”