Mechanical properties and electrical resistivity of portland limestone cement concrete systems containing greater than 15% limestone and supplementary cementitious materials

•Strong, durable concrete can be produced with PLC and SCMs.•Low-clinker PLC concrete offers significant environmental benefits.•Effective w/cm is more reliable predictor of compressive strength than actual w/cm. This investigation explored the feasibility of producing strong, good quality, durable concrete in low-clinker systems (less than 50% clinker in some cases). The low-clinker content was achieved by combining interground portland limestone cement (PLC) with high limestone contents and different supplementary cementitious materials (SCMs). Seven cements, with approximate limestone contents between 3% and 31%, from two cement plants were used, in combination with SCMs, in forty-two different mixtures with water-cementitious materials ratios (w/cm) of 0.40 and 0.45. The SCMs included Class F and C fly ashes, Grade 100 slag, and silica fume. Mechanical properties (compressive strength, tensile strength, elastic modulus) and electrical resistivity were measured at 1, 7, 28, and 91 days. Similar compressive strengths were observed for mixtures with equivalent effective w/cm ratios. Although, the combination of PLCs with SCMs for very low-clinker systems resulted in decreased compressive strength, an increase in electrical resistivity was observed. More importantly, strong, good-quality concrete can be produced without sacrificing environmental benefits.