Tensile Behavior of Strain Hardening Cementitious Composites (SHCC) Containing Reactive Recycled Powder from Various C&D Waste

This work investigates the feasibility of utilizing reactive recycled powder (RP) from construction and demolition (C&D) waste as supplementary cementitious material (SCM) to achieve a ductile strain hardening cementitious composites (SHCC). The recycled mortar powder (RMP) from mortar waste, recycled concrete powder (RCP) from concrete waste and recycled brick powder (RBP) from clay brick waste were first prepared, and the micro-properties and tensile behavior of SHCC containing various types and replacement ratios of RPs were determined. The incorporated RP promotes pozzolanic and filler effects, while the hydration products in cementitious materials decrease with RP incorporation; therefore, the incorporated RP decreases the compressive strength of SHCC. Attributed to the reduction in the matrix strength, the incorporated RP increases the crack-bridging extent and ductility of SHCC; the irregular micro-structure and high reactivity of RP also help the strain-hardening performance of the prepared SHCC. In addition, the strain-hardening performance of SHCC containing RMP and RBP is surperior to that of SHCC with RCP and is slightly lower than that of SHCC with fly ash (FA); for instance, the ultimate strain of SHCC containing 54% FA, RMP, RCP and RBP is 3.67%, 3.61%, 2.52% and 3.53%, respectively. In addition, the strain-hardening behavior of an SHCC doubled mix with FA and RMP or RBP has a similar ultimate strain and a higher ultimate stress than SHCC containing only FA.