Relationships between microstructure and transport properties in mortar containing recycled ceramic powder

Sustainable utilization of ceramic wastes in construction has gained increasing interest, but the microstructure and transport properties of ceramic-modified construction materials remain to be explored before in-situ engineering application. This paper presents an experimental study on microstructure, mechanical properties and transport properties of cement mortars containing different percentages of ceramic powders (CPs) up to 40%. Microstructure of CP-cement mortars was measured using mercury intrusion porosimetry, water vapor sorption isotherm and scanning electron microscopy techniques. Mechanical properties including compressive strength and flexural strength as well as transport properties including gas permeability and capillary sorptivity were measured. Results indicate that ceramic powder can greatly refine the pore structure of CP-cement mortars. Because of the homogenization and densification effects of ceramic powder on mortar matrices and interfacial transition zones, the compressive and flexural strengths of CP-cement mortars at 180 d are around 80 MPa and 10 MPa, respectively. Both gas permeability and capillary sorptivity decrease substantially as ceramic powder content increases and exhibit linear correlations with pore structure characteristics such as total porosity and critical pore size. Ceramic powder can lower the manufacture costs of concrete and obtain better durability. Therefore, ceramic powder can be considered as a promising supplementary material to develop sustainable and durable cement-based materials for future engineering applications. (C) 2020 Elsevier Ltd. All rights reserved.