Long-term properties of concrete containing limestone powder

Plain cement concrete (employed as reference) and three concretes containing limestone powder (replacement ratios of 10, 20, and 30%) were designed. The compressive strengths of the four concretes were close to each other by adjusting the water to binder ratios. The long-term (as long as 5 years) properties of hardened paste and concrete were determined under the condition of equal 28-day compressive strength of concrete. The results show that limestone powder can react with cement but its reaction degree is very low even at 5 years. The addition of limestone powder tends to increase the long-term connected porosity of concrete and the pore structure of hardened paste. The strength and resistance to chloride penetration of the concrete containing limestone powder increase much less than those of plain cement concrete at late ages. When the replacement ratio of limestone powder exceeds 10%, the resistance to carbonation of concrete decreases significantly, but the drying shrinkage of concrete is reduced.