Investigation of NWC and Structural LWC Using Local Material in the UAE Exposed to Elevated Temperatures

In response to the rapid urbanization and local boom in UAE’s development and real estate industry, concrete is continuously in demand in alarming amounts contributing to the climate change effect. Research has continuously shown that lightweight concrete (LWC) is a potential sustainable alternative for normal weight concrete (NWC) due to incorporation of cement alternatives within the mix, higher resource efficiency, and enhanced thermal insulation. This paper investigates the residual properties of NWC and structural LWC at room temperature and when exposed to the following steady-state temperatures: 100°C, 200°C, 400°C, 600°C, and 800°C. Results show that LWC exhibit higher fire performance than NWC. At failure, NWC specimens majorly reported cone and split failure modes. The LWC specimens displayed mostly columnar failure modes. Spalling of concrete was first reported at 600°C on LWC at the corners of the specimens. At 800°C, surface spalling was reported on NWC only, indicating the higher fire resistive property of LWC. After heat exposure, discoloration was first observed in all specimens at 400°C. The compressive strength of both types of concrete initially increased after high-temperature exposure. Residual strength reported increase up to 200°C and 400°C for NWC and LWC, respectively. Consequently, significant decrease in compressive strength reaching around 20% of the original compressive strength when exposed to 800°C. Results showed that NWC experiences more reduction in residual strength than LWC, supporting that LWC is a promising construction material in enhancing structural fire safety.