Effect of Coal Gangue Grain Size on Strength of Foam Concrete

Abstract

This work shows that the grain size of coal gangue has affects on the strength of foam concrete with coal gangue. Coal gangue was crushed and separated into three grades sand according to the size which were 0.16-0.6mm, 0.6-2.5mm and 2.5-5mm. Then these coal gangue sand was used to manufacture foam concrete with a density of about 850kg/m3. The compressive, flexural strength, water absorption and softening coefficient of coal gangue foam concrete were tested. The results show that compressive strength of foam concrete exhibits a monotonic decreasing while coal gangue content increases and the decreasing rate would accelerate with the increasing of grain size. And the water absorption increased with the coal gangue content and grain size increasing. Small size coal gangue could improve the water absorption resistance. The coal gangue foam concrete is a water-resistant material and the softening coefficient is above 00.85, when the diameter of coal gangue fine aggregate is below 2.5 mm.