Portland-composite and composite cement concretes made with coarse recycled and recycled glass sand aggregates: Engineering and durability properties

Sustainable development approach demands the use of environmentally friendly materials. One possible way to encourage sustainable approach is via use of Portland cement (PC) replacement through use of permitted cement constituents in conformity with BS EN 197-1, to lower carbon footprint, and use of recycled aggregates as permitted within BS 8500, to encourage sustainability. Thus, this research study aimed to produce low carbon and sustainable concrete. For this aim, engineering and durability properties of equal 28-day design strength (40 and 50 N/mm2) concretes made with Portland-composite and composite cements, CEM II/B-M and CEM V/A respectively, and partially substituted coarse recycled (RA) and washed recycled glass sand (RGS), 25% and 15% respectively, aggregates was investigated. The loss of workability was found to be larger for particularly CEM V/A and recycled aggregate concrete (RAC) mixes. Studies of hardened concrete properties, comprising bulk engineering properties (compressive cube and cylinder strength, flexural strength, drying shrinkage) and durability (initial surface absorption) showed enhanced performance for CEM II/B-M and CEM V/A mixes of equivalent strength natural aggregate concrete mixes (NAC), except resistance to carbonation. However, the use of CEM II/B-M and CEM V cements in RAC mixes slightly reduced the engineering and durability properties compared to corresponding NAC mixes.