Influence of Curing Conditions on the Compressive Strength of Foamed Concrete

Abstract

The foamed concrete (500 kg/m3 and 800 kg/m3) was produced by physical foaming using ordinary Portland cement (P.O 42.5R), vegetable protein foaming agent, fly ash from power plant and fly ash cenospheres (FACs) as raw materials. The air-void structure and the hydration products of the samples were characterized by SEM, XRD and other testing methods. The influence of standard curing, immersed curing with saturated Ca(OH)2 water solution, water spray curing and air curing on the strength and pore wall density of hardened foamed concrete were explored. The results showed that the lower the relative humidity in the curing process was, the more porous existed in the pore wall of the foamed concrete. The relative humidity imposed large influence on the compressive strength of the low-density foamed concrete, which was contrary in case of high-density foamed concrete. The compressive strength of the foamed concrete mixed with FACs was largely enhanced and the FACs played a more important role in the improvement of the strength of the low-density foamed concrete than that of the high-density foamed concrete.