Application research on durability and low carbonation of concrete modified with limestone powder and silica ash

Abstract

Abstract In order to reduce the carbon emissions caused by the use of a large amount of concrete during tunnel construction and achieve the goal of green and low-carbon construction. This paper develops a low- carbon modified concrete by adding limestone powder (LP) and silica fume (SF) on the basis of ordinary concrete mixture. This paper analyzes the effects of different LP and SF dosages as well as the water-to-cement (w/c) ratios on rheological properties, early-age heat release and compressive strength of the material. The workability of the cementitious material was further comprehensively evaluated by introducing the expansion and water absorption indicators. The results confirmed that the incorporation of more than 15% LP led to a slight decrease in the strength of the cementitious material; however, it improved the pumpability and significantly reduced early-age heat release of the cementitious material, which contributed to the control of temperature-induced cracking in cementitious material. Also, the addition of SF with a content of more than 5% could further optimize the pumpability, which was beneficial for long-distance pumping of high-performance cementitious materials. Modified concrete has good mechanical properties, good pumpability, and low hydration heat. This study developed a low-carbon concrete material for green construction of tunnel construction, further promoting the efficient and clean utilization of LP and SF.