3 research outputs found
Effects of heating durations on normal concrete residual properties: compressive strength and mass loss
This study investigates the effects of high temperature with five different heating
durations on residual properties of 30 MPa normal concrete. Concrete cubes were being heated
up to 600°C for 30, 60, 90, 120 and 150 minutes. The temperature will keep constant for 30,
60, 90, 120 and 150 minutes. The standard temperature-time curve ISO 834 is referred to. After
heating the specimen were left to cool in the furnace and removed. After cooling down to
ambient temperature, the residual mass and residual compressive strength were observed. The
obtained result shows that, the compressive strength of concrete decrease as the heating
duration increases. This heating duration influence, might affects the loss of free water present
and decomposition of hydration products in concrete. As the heating duration increases, the
amount of water evaporated also increases led to loss in concrete mass .Conclusively, the
percentage of mass and compressive strength loss increased as the heating duration increased
Evaluation of bond strength between fire-damaged normal concrete substance and ultra-high-performance fiber-reinforced concrete as a repair material
This study aims to investigate and compare the interfacial bond characteristics between fire-damaged normal concrete substrate and ultra-high-performance fiber-reinforced concrete (UHPFRC) as a repair material. Design/methodology/approach - First, fire-damaged normal concrete was prepared. Then, with a cast surface, the substrate was subjected to different surface moisture conditions. Three types of moisture conditions were set, namely, air dry, saturated surface dry (SSD) and wet. Slant shear and splitting cylinder tests were conducted to determine the interfacial bond strength of the composite. Findings - In general, results indicate that surface moisture conditions significantly influence bond strength. The substrate under SSD condition exhibited the highest bond strength. The findings suggest that UHPFRC is a promising material for the repair and reuse of fire-damaged concrete structures. Originality/value - This study compares the bond strength between fire-damaged normal concrete and UHPRC