"Pore Structure, Strength and Carbonation of Cement Pastes Containing Ground Granulated Blast-Furnace Slag"

Abstract

This paper describes the test results obtained on the pore structure, strength and carbonation of hardened cement pastes containing ground granulated blast-furnace slag (GGBS). Five different types of ground granulated blast-furnace slag with Blaine finenesses of 400, 800, 1100 and 3000 m squared/kg respectively, are used as a partial replacement for normal portland cement by 15, 30, 50 and 70%. The porosity and threshold radius of hardened cement pastes decrease remarkably with the increases of GGBS fineness at the early ages. They also decrease with the increases of GGBS content, except that of 400 m squared/kg Blaine fineness in the long term. The high fineness GGBS enhances the early strength development of hardened cement paste containing GGBS and reduces its rate of carbonation. It is made clear that the GGBS with Blaine fineness of 1100 m squared/kg is most satisfactory for making the high strength and high durability hardened cement pastes. Furthermore, the effects of the porosity and threshold radius on strength and carbonation of hardened cement paste containing GGBS are examined. Close relationships are observed between strength, carbonation and pore structure of hardened cement paste containing GGBS regardless of GGBS fineness and GGBS content.