Effect of cement fineness and limestone additions on mortar properties

Abstract

The influences of cement fineness on compressive and flexural strength development and durability of mortars and heat of hydration were studied at 23°C and 50°C curing temperatures with six cements manufactured from a single clinker but with different finenesses ranging from 3100 to 4650 cm2/g. The effects of 2-10% limestone addition to cement on strength development and sulphate expansion were also investigated. Compressive strength was significantly increased by higher fineness at all ages up to 180 days, while flexural strength was increased only at early ages. Finer cement had less strength increase after 24 hour heat curing at 50°C and more strength reduction at 28 days than coarser cement. Heat curing was not beneficial for cement containing CaCO3. Higher fineness showed no significant influence on chloride permeability and freezing and thawing resistance. Limestone addition reduced chloride permeability and sulphate expansion of mortars. Among all the fineness tests used, the standard Blaine specific surface area exhibited the best correlation with mortar strength development.