Abstract
Replacing a portion of the clinker in cementitious systems with limestone is one strategy to reduce greenhouse gas emissions. This study was designed to evaluate three performance parameters: heat of hydration, drying shrinkage, and flexural strength of portland limestone cement (PLC) mixtures. Eighty mortar and paste mixtures were prepared using Type II/V ordinary portland cement (OPC), PLC, and OPC with ground limestone (OPC + LS) with and without supplementary cementitious materials (SCMs). The PLC was made in the same commercial facilities using the same raw materials as the OPC (ASTM C150, Standard Specification for Portland Cement, Type II/V). The PLC and OPC + LS paste mixtures had a heat of hydration (extent of reaction) that was within 10 % of the OPC paste mixtures, whereas the heat of hydration for PLC and OPC + LS paste mixtures with slag were comparable with corresponding OPC-slag paste mixtures. Compared with OPC, the PLC and OPC + LS did not substantially affect the drying shrinkage for most mortar mixtures, though increases of 7–8 % were noticed for mortar mixtures with slag. At 7 days, some PLC and OPC + LS mortar systems demonstrated up to a 19.9 % reduction in flexural strength (M0: plain system [i.e., no SCM], M1, M2, which were the systems with fly ash), though a 5–7 % greater strength was noticed with slag. At later ages, the flexural strength difference between the PLC or OPC + LS and OPC mixtures was less pronounced (±5 % of each at 90 days) and was not statistically different.