Ali Allahverdi - Cement Research Center, School of Chemical Engineering, Iran University of Science and Technology, Narmak ۱۶۸۴۶۱۳۱۱۴, Tehran, Iran
Babak Shaverdi - Cement Research Center, School of Chemical Engineering, Iran University of Science and Technology, Narmak ۱۶۸۴۶۱۳۱۱۴, Tehran, Iran
Ebrahim Najafi Kani - Cement Research Center, School of Chemical Engineering, Iran University of Science and Technology, Narmak ۱۶۸۴۶۱۳۱۱۴, Tehran, Iran

This work is devoted to determine the optimum dosage and composition of an alkali-activator suitable for activating blast-furnace slag from Isfahan steel plant. Sodium hydroxide and water glass were used to prepare a number of mixes from ground granulated blast-furnace slag. The mixes were designed in such a way to contain different levels of sodium oxide including 1, 2, 3, 4, 5, and 6% by weight of dry binder with activators having different silica modulus (SiO2/Na2O) of 0.3, 0.4, 0.5, and 0.6. The most important physico-mechanical properties of the binder including workability, initial and final setting times, 28-day compressive strength, total 90-day shrinkage, and efflorescence were measured. After observation of the results of 28-day compressive strength and efflorescence test, mixes with acceptable amount of efflorescence which contain Na2O contents of 1, 2 and 3 % by weight of dry binder were chosen for investigating their autogenous and drying shrinkages. The results confirm the possibility of achieving 28-day compressive strengths up to 37.5 and 50 MPa for mixes with sodium oxide content of 1 and 2 wt% respectively, which were chosen as the mixes having optimum dosage of activator.

Alkali activator, Blast furnace slag, Compressive strength, Shrinkage