Effect of Temperature and Humidity Conditions on the Strength of Blast-Furnace Slag Cement Concrete

Abstract

This paper will present results regarding the effects of various temperature and humidity environments on the compressive strength of concretes containing blast furnace slag cement (BFSC) and ordinary portland cement (OPC). Three types of blended cements containing 4.5, 35, and 68 percent slag weight replacements of portland cement were used. The specimens were stored in locations with controlled environments, such as 35oC (95 percent relative humidity), standard ambient temperature 23oC (lime water, sealed with polypropylene bag, 100 percent relative humidity fog room, and 50 percent relative humidity drying room), and 10oC. Test results indicate that the temperature effect on the initial rate of strength development of BFSC concrete is more sensitive than that of OPC concrete; high temperature accelerates the strength gain and low temperature suppresses the initial strength increase of BFSC concrete. Higher ultimate strength was achieved for the 4.5 and 35 percent BFSC well-cured concretes as compared to OPC concrete. However, the inadequate supply of reactive materials resulted in lower compressive strength for the 68 percent BFSC concrete. Under dry conditions, concrete with high slag content stopped its strength development as excess loss of moisture hindered the hydration process of cement. Strength degradation was also found for high slag content BFSC concrete.