Durability of high-performance concrete containing metakaolin and Portland limestone cement against chloride attack

High-performance concrete (HPC) as an engineered concrete has become very popular in recent decades, mainly due to the increasing demand for high mechanical property, high durability performance and long service life in construction projects. For achieving the sustainable development goals in the cement industry, partial replacement of Portland cement by mineral additives such as metakaolin (MK) and limestone powder is known as a usual method. This study investigates the properties of high-performance concrete mixtures containing ternary cementitious blends of MK and Portland limestone cement (PLC), in terms of compressive strength, water absorption, surface electrical resistivity and Rapid Chloride Migration Test (RCMT) up to ۹۰ days. Also, a semi-quantitative analysis of the X-ray Diffraction (XRD) test conducted to compare the pozzolanic activity of different pastes. The percentages of MK that replaced with PLC in this research were ۰%, ۱۰%, ۱۲.۵% and ۱۵% by mass. Generally, Results showed that high-performance concrete specimens prepared with replacing ۱۵% of PLC with MK presented the worst and best performance of the chloride migration diffusion among the studied mixtures at ۲۸ and ۹۰ days, respectively. Based on results, limestone powder in PLC as a water-absorbent material caused the reduction of MK activity at early ages up to ۲۸ days. Finally, the desirable effect of using any replacement of MK in the PLC concretes containing ۱۵% limestone powder was demonstrated at ۹۰ days.

Keywords:

Durability , Chloride attack , Metakaolin (MK) , Portland-Limestone Cement (PLC) , High-Performance Concrete (HPC)