Alkali activated slag concretes designed for a desired slump, strength and chloride diffusivity. (30th November 2018)

• Record Type: Journal Article
• Authors: Bondar, Dali; Ma, Qianmin; Soutsos, Marios; Basheer, Muhammed; Provis, John L.; Nanukuttan, Sreejith
• Is Part Of: Construction & building materials. Volume 190(2018)
• Page Start: 191
• Page End: 199
• Publication Date: 2018-11-30
• Subjects: Alkali activated slag concretes (AASC) -- Workability -- Strength -- Chloride diffusion and chloride binding capacity; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2018.09.124
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: AAS concretes can be designed for different workability and different grades of concrete. The compressive strength of AASC are strongly proportional to the SiO2 content in the activator. Chloride diffusion coefficients of AAS concretes are low. Chloride diffusivity of AASC shows that the excess water is not affecting the pores in AASC as PC. AASC can be designed for a water/binder ratio needed for a specified mechanical performance. AASC binding capacity increases by increasing the paste and/or silica content of the activator. Abstract: Ground granulated blast furnace slag (GGBS) is the most common industrial by-product used as a precursor for alkali activated binders due to its fast setting, simple curing needs, and good early age strength gain. There are conflicting findings on the chloride penetration resistance of such binders and more information is required regarding the suitability of this type of binder material for chloride environments. This article outlines the findings of investigation of alkali activated slag concretes (AASC), to provide a comprehensive view of the effect of mix design variables on slump, strength, and chloride transport and binding. It is concluded that AASC can be designed for different workability and different grades of concrete. The diffusivity results demonstrate that the addition of excess water does not directly control the pore structure/connectivity in AASC as it does for Portland cement, and therefore AASC can be designed based on the water/binder ratio needed for a specified mechanical performance. The chloride binding capacity increased as the paste content of the concrete and/or the silica content of the activator was increased.