Influence of matrix-modification and fiber-hybridization on high-temperature residual mechanical performance of strain-hardening cementitious composites

This research experimentally examines the influence of matrix-modification and fiber-hybridization on the residual mechanical properties and bond behavior (with steel reinforcement) of Strain-Hardening Cementitious Composites (SHCC) after exposure to high temperatures. The matrix-modification entailed replacing fly ash and silica sand used in conventional SHCC matrix with slag and calcium carbonate (CC) powder for improving the thermal stability of the matrix. Furthermore, a combination of steel and polyvinyl alcohol (PVA) fibers was used to prevent brittle failure of SHCC after the melting of PVA fibers around 230 °C. Four SHCC materials (including conventional SHCC), corresponding to the four possible combinations of the aforementioned modifications, were subjected to temperatures of up to 800 °C. Residual mechanical properties and bond behavior of all the materials were experimentally determined after exposure to high temperatures. The improvement in the thermal stability of the cementitious matrix and fiber-hybridization resulted in significant enhancement of the residual mechanical properties and bond behavior of SHCC exposed to temperatures of up to 600 °C.