Properties of Air-Entrained Pumice Lightweight Aggregate Concrete and a Freezing-Resistance Forecasting Model

Abstract

This study investigates the impact of air content on the mechanical properties and resistance of natural pumice lightweight aggregate concrete to freezing. The distributional characteristics of bubbles in pumice lightweight aggregate concrete are analyzed, and a freezing-resistance forecasting model for air-entrained pumice lightweight aggregate concrete is established. Experimental results show that the distribution of bubbles in natural pumice lightweight aggregate concrete is different from that in ordinary concrete. More bubbles are found in pumice, and fewer bubbles are found in mortar. The air content of non-air-entrained pumice lightweight aggregate concrete is almost the optimal air content of ordinary concrete. However, aggregate concrete has poor resistance to freezing. The optimal air content of ordinary concrete does not apply to pumice lightweight aggregate concrete. Significantly improved freezing resistance is observed after air entrainment. However, the cube compressive strength of pumice lightweight aggregate concrete exhibited faster loss than that of ordinary concrete. The mean strength loss reaches 8.74% if air content is increased by l%. Cube compressive strength is an important mechanical index, together with freezing-resistance test results, when establishing a freezing-resistance forecasting model of natural pumice lightweight aggregate concrete.