Strategies to enhance the moisture-barrier qualities of concrete mixtures to improve their durability

Abstract

Moisture transport in concrete significantly impacts its durability attribute, which in turn affects the useful service life of the built concrete infrastructure. A host of physical, chemical, and mechanical deterioration processes of concrete depend on the presence of moisture inside the concrete. Enhancement of the moisture-barrier characteristic of concrete can thus be the key to improving its durability. This paper reports the test results of various strategies implemented to reduce the moisture transport into concrete. These strategies include (i) use of fly ash and silica fume as partial replacement of cement for refinement of capillary porosity, discontinuity of pores, and refinement of the chemistry of hydrated cement matrix; (ii) use of milled waste glass as partial replacement of cement to refine the microstructure of cementitious mixture (iii) use of hydrophobic additives to reduce the affinity of capillary pore surfaces to moisture; and (iv) use of polymer emulsion to line capillary pore surfaces to cause partial blockage of the capillary pore system. Five different concrete mixtures including a control mixture were prepared using the above formulations and tested for moisture sorption, acid attack resistance, abrasion resistance, and compressive strength characteristics at 28 and 90 days of concrete age. Test results indicated enhancement in compressive strength, moisture resistance, and other durability characteristics of the modified mix formulations compared to that of control mixture. Mix formulation incorporating fly ash and silica fume as partial replacement of cement proved to be the most effective combination for achieving the desired improvements in mechanical and durability attributes of concrete. The findings of this study are expected to provide guidelines for designing concrete mixtures with enhanced durability when exposed to aggressive environmental conditions.[copyright information to be updated in production process.]