Improving workability and mechanical properties of one-part waste brick power based-binders with superplasticizers

Abstract

This paper is based on a one-part binders (calcium carbide residue–waste red brick powder-based alkali-activated materials (CWAAMs)) similar to cement. CWAAMs can promote the recycling and value-added of construction waste and industrial solid waste all over the world. However, the poor workability of CWAAMs hinders their engineering application. Therefore, this paper focuses on the effects of common superplasticizers (polycarboxylate (PC), melamine (M), naphthalene (N)) on the properties of CWAAMs. The adaptability result showed that the improvement effect of the flowability of the superplasticizers was PC > M > N; the fluidity improvement effect of PC on CWAAMs was 64.21% of that of ordinary Portland cement (OPC, 42.5). In addition, the stability of superplasticizers in CWAAMs was PC > M > N. The development of strength and microstructure of CWAAMs under different conditions (dosage and type of, L/S value, material proportion adjustment) were evaluated. With a low L/S value (0.26), the 60d compressive strength of CWAAMs adding PC reached 74.62 MPa. The adjustment of material proportion showed that at least 15 wt% of calcium carbide residue can meet the alkalinity required for CWAAMs reaction. The 28d Ef and Cf (Energy consumption and carbon emission per unit compressive strength) of CWAAMs were as low as 7.208 and 2.078, which were 7.24% and 11.48% of OPC, respectively; the compressive strength development of CWAAMs within 120d conformed to the logarithmic function, and the adjusted R-squared was 0.99186. The later strength will further improve the sustainability of CWAAMs.