Influences of Accelerators on Compressive Strength Development of Composite Cements

Low‐clinker composite cements often have the disadvantage of lower early compressive strength. Hardening accelerators can increase the early compressive strength of Portland cement at the expense of reduced late strength. The extent to which different hardening accelerators influence the compressive strength development of low‐clinker composite cements containing granulated blast furnace slag and limestone was systematically investigated using compressive strength test, ultrasound transmission experiments and heat flow calorimetry.

The results show that the accelerator must always be adapted to the particular composite cement in order to increase the early compressive strength. Synergetic effects of cement constituents besides clinker can partly compensate for the reduced late strength of accelerated systems.