Title: Chemical Modelling in Blended Cement Systems

Author(s): Mark Atkins, Donald E. Macphee, and Frederik P. Glasser

Publication: Symposium Paper

Volume: 114

Issue:

Appears on pages(s): 73-96

Keywords: blast furnace slag; blended cements; chemical properties; models; permeability; portland cements; strength; Materials Research

DOI: 10.14359/1858

Date: 5/1/1989

Abstract:
Blast furnace slags and pulverized fly ash have been used extensively as additives to ordinary portland cement (OPC) to make low-permeability pastes with adequate long-term strengths. These properties are a consequence of phase development in the matrix that proceeds nonuniformly because the OPC clinker and blending agent react at different rates. Also, sheaths of hydration products forming around anhydrous grains inhibit reaction. This complicates our interpretation of the properties of blended cement systems because phases observed as products on laboratory time scales are not necessarily representative of the steady state assemblages. The aqueous chemistry is also subject to time-dependent changes since solution composition is related to that of the coexisting solids. In some applications, it is necessary to predict long-term physicochemical properties. This can be achieved through modeling, based on sound scientific principles, and using as much information as realistic from immature systems. Paper describes progress in model development and verification.