LIMESTONE AS A RETARDER AND FILLER IN LIMESTONE BLENDED CEMENT

In this investigation, four blended cement pastes were made from portl and cement and limestone by using the suitable water of consistency of each paste. The influence of limestone replacement was studied throug h the determination of non-evaporable water content, free lime content , total porosity, compressive strength and pH value for each blended c ement paste. The blended cements were compared with the ordinary Portl and cement. The pH values increase with the increase of limestone addi tion as well as with curing lime. Also, the addition of limestone enha nces the rate of hydration as measured from the combined water content s. In the light the results obtained, blended cement pastes and mortar s can be made by the addition of limestone up to 20 % giving reasonabl e mechanical properties and suitable passivation of reinforcing steel in the concrete.