In this research, the influence of coarse aggregate type and incorporation of polypropylene fibres on the mechanical properties of normal concrete (NC) and self compacting concrete (SCC) were investigated. Three types of local aggregates namely natural gravel, basalt and dolomite were used. Fire resistance of the produced concrete in terms of residual strengths and spalling was studied. Different elevated degrees of temperature of 200, 400, 600 and 800 °C were considered. The latter degree of temperature (800 °C) was maintained constant while the effect of exposure durations of 15, 30, 60 and 120 minutes were investigated. Compressive strength, indirect tensile strength, porosity, near surface absorption and spalling were measured before and after exposure to elevated degrees of temperature.
The results indicated that, aggregate type has a minor effect on the concrete resistance to fire. However dolomite aggregates provided the highest resistance to fire while natural aggregate gave the least resistance. The incorporation of polypropylene fibres improved the indirect tensile strength results as well as the concrete resistance to spalling. It was also recorded that the degradation of the mechanical and permeation properties of SCC increases with increasing the degree of elevated temperature. It is worth mentioning that the performance of SCC exposed to high elevated degrees of temperature is better than that of the NC.
|
