Compressive strength prediction of lightweight foamed concrete with various densities

A research has been undertaken to study the compressive strength of foamed concrete with various concrete density. This paper reports experimental investigation on lightweight foamed concrete of 300, 600, 800 and 1000 kg/m³ densities and correlates compressive strength and density for further strength prediction. A total of 72 foamed concrete cubes with various densities and water cement ratio were prepared and tested for compressive strength at the concrete age of 7 and 28 days. Inverted slump and flow table spread value were obtained based on the test method stated in ASTM C1611. The foams were produced by using foam generator by mixing them with cement mortar (Ordinary Portland Cement, OPC and dry sand of size 850μm). The experimental results showed the highest compressive strength was recorded as 2 MPa for the density of 1000kg/m³ and water cement ratio of 0.6. The results revealed that consistency of the foamed concrete is in the range of 0.97 to 1.03, whereas stability index is in the range of 0.98 to 1.19 which showed the bubbles in the foamed concrete were stable during casting and curing process. A prediction model with exponential equations were proposed for foamed concrete compression strength with different water-cement ratio and it can be preliminary used to predict the foamed concrete strength. (paper)