Chloride ingress in concrete: limestone addition effects

Analysis and evaluation of experimental results of chloride ingress, and chloride-induced corrosion resistance, of concrete made with Portland limestone cement (PLC), mined from 169 globally published literature from 32 countries since 1989, yielding a 20,500-data matrix are presented. This shows that the chloride ingress in concrete increases with increasing limestone (LS) content, within the range permitted in BS EN 197-1:2011. This effect however, is less for the PLC concrete mixes designed for strength equal to the corresponding Portland cement (PC) concrete mixes than those designed on equal water/cement basis. The results showed that Eurocode 2 specifications for chloride exposure, in terms of characteristic cube strength of concrete, or w/c ratio, may need to be reviewed for the use of LS with PC. Other influencing factors, including, cement content, LS fineness, method of producing PLC, aggregate volume content and particle size, combined chloride and sulphate environment, curing, exposure temperature, have also been studied. A comparison has been made for the performance of PLC concrete in terms of pore structure and related properties, strength, carbonation and chloride ingress. Procedures to improve the resistance of PLC to chloride ingress in concrete are proposed.