Effect of recycled aggregate utilization on strength properties of lightweight concrete facade having a self-cleaning characteristic

Abstract

Utilization of lightweight concrete results in a reduction in the weight of the structure, leading to lower destructive effects of seismic forces on the building. Additionally, in today’s conditions where more efficient energy use is desired, there is an increasing interest in the use of lightweight concrete facade panels due to their superior performance in terms of heat insulation. It is known that pollutants such as COx and NOx adhere to facades over time, causing pollution and visual deterioration. It was reported that materials with photocatalytic properties are used in concrete elements to prevent such issues. In this context, the use of self-cleaning concrete facades containing materials with photocatalytic properties has become more prevalent in recent years. Among the many semiconductor materials used in the production of self-cleaning concrete, it is understood that the use of TiO2 is more widespread due to the various advantages it offers. On the other hand, it was reported that urbanization is increasing, and the volume of construction waste is rapidly growing, particularly after severe earthquakes. In this context, promoting the use of recycled concrete waste and efficiently disposing of construction and demolition waste are of great importance for the European Green Deal. This study examines the effect of using recycled concrete aggregate on the self-cleaning properties of lightweight concrete mixtures (SCLWC) compressive and flexural strength performance. For this purpose, an SCLWC containing 1% TiO2 and 100% pumice aggregate was prepared. By substituting recycled concrete aggregate with pumice aggregate at 25% and 50% rates, two different SCLWCs with self-cleaning properties were produced. The compressive strength and flexural strength performances of the produced mixtures were examined. It was observed that the increase in pumice aggregate content caused a decrease in both strength performances. It was observed that the increase in pumice aggregate content caused a decrease of up to 53% and 7% in compressive and flexural strength performance, respectively.