Effect of aggregate coating thickness on pore structure features and properties of porous ecological concrete

The coating thickness of coarse aggregate to some extent determines pore structure features and the properties of porous ecological concrete. In this paper, analyses of pore structure features and properties are carried out by designing different coating thicknesses. The porosity of porous ecological concrete is determined by volumetric and area fraction methods. Stereology and mathematical-morphology-based methods are used to extract the pore structure features. Results showed that the pore structure features using two methods related well to each other. The extracted pore structure features were found to be linearly related to the coating thickness. The porous ecological concrete with thinner coating thickness possessed better pore structure features and worse mechanical property. When the coating thickness was 590 μm, the porosity of the porous ecological concrete was above 26%, the 28-day pH value was 9·72, the 28-day compressive strength was 12·1 MPa and the effective pore size was more than 4·6 mm.