Effect of Using Recycled Lightweight Aggregate on the Properties of Concrete

Abstract

In this research, a study was carried out to produce a lightweight concrete from a recycled lightweight concrete. Crushed cellular concrete (locally known as Thermostone) was used as partial replacement for both the coarse and fine aggregates in different percentages. The specimens were tested for compressive strength using two different methods: the first involved testing the specimens at room temperature in saturated surface dry conditions, whereas the second method consisted of testing the specimens immediately after heating them to 55oC. The results showed that the compressive strength reduced with increasing the recycled lightweight concrete aggregate content. The results also showed that the compressive strength of the heated specimens was lower than that for the specimens tested in saturated dry surface conditions for all of the mixtures. However, the difference decreased with increasing the recycled aggregate content. It was also noted that the density of the specimens and the coefficient of thermal conductivity decreased with increasing the replacement ratio, which makes this type of concrete useful in places where better thermal insulation is required.