Dry-cast concrete masonry products: properties and durabilityThis article is one of a selection of papers published in this Special Issue on Masonry.

Abstract

Performance of dry-cast concrete masonry products (DCCMPs), which are becoming the product of choice for many applications, has yet to be assessed in a comprehensive manner. This study was undertaken to investigate the effects of mix design and manufacturing parameters on the mechanical and transport properties, as well as the freeze–thaw (F/T) durabilities, of DCCMPs. The variables studied were water to cement ratio, mixing time, vibration time, and curing regime. Freeze–thaw durability was assessed in accordance with the American Society for Testing and Materials (ASTM) standard C1262 by exposing specimens to four conditions: water, 3% NaCl, 4% CaCl2, and 4% MgCl2 solutions. Results revealed that 3% NaCl exposure yielded the most mass loss due to scaling, whereas 4% MgCl2 exposure exhibited the least. Increase in either water content, vibration time, mixing time, or use of moist curing led to improvement in the mechanical properties, refinement of large pores in the range of 40 to 400 μm, reduction of total porosity, and enhancement of F/T durability of capstones. Ionic sorptivity yielded a strong statistical correlation with mass loss due to F/T action in the presence of 3% NaCl and 4% CaCl2.