Elevated Temperature Performance of Reactive Powder Concrete Containing Recycled Fine Aggregates

Abstract

This study examines the effect of elevated temperature on various properties of reactive powder concrete (RPC) containing varying percentages of recycled fine aggregates as sand replacement. Recycled fine aggregates were collected from two sources, i.e., demolished normal strength concrete and demolished RPC. The specimens were prepared using 25%, 50%, and 75% replacement of natural sand with recycled fine aggregates, exposed to two different curing conditions and were subjected to four temperatures, i.e., 25, 200, 400, and 600 °C. Later, the specimens were tested for mass loss, compressive strength test, split-tensile strength test, flexural strength test, and water absorption test at all temperature ranges. Results determined that although the mechanical properties degraded with the temperature rise, the recycled aggregates can be employed as a partial replacement of natural sand in RPC without causing a significant decrease in the performance of RPC, and can help to produce more sustainable RPC by using recycled aggregates.

Autoclave-free ultra-early strength concrete preparation using an early strength agent and microstructure properties

“…Under autoclave conditions, large amounts of hydration products with high crystallinity and large size were generated in short time and wrapped surround the unreacted cement, limited the forward hydration, and made the concrete more brittle. [9][10][11] Water vapor violently transferred during autoclave curing, causing weak permeability from larger porosity and more connected pores. [12][13][14] Hence, the research about early strength concrete with autoclave-free curing was signicantly important.…”