Orateur
Description
The use of recycled concrete aggregate (RCA) in concrete production can reduce concrete costs by reducing the quantity of natural aggregate (NA) used in the production of concrete due to the low cost of RCA in comparison with the cost of NA. Also, the use of RCA in concrete production results in the reduction of CO2 emissions associated with the NA extraction, transportation and the reduction of construction and demolition wastes (CDW) being placed in landfills and by the way ensuring rational use of natural resources. This paper assesses the possibility of using waste materials such as RCA in the production of Self compacting concrete (SCC) and the inclusion of FA to reduce the carbon footprint of the concrete. Coarse RCA was replaced at 0, 20, 40, 60, 80 and 100 wt% of coarse limestone aggregate and six SCC mixes were produced. The water/bind ratio, cement content, water/powder ratio and slump flow values were kept constant as 0.42, 340 kg/m3, 0.32 and 710±10 mm. Fresh characteristics of SCC mixes were assessed by using slump flow, V-Funnel, L-Box, U-Box and J-Ring tests. The mechanical and transport properties of hardened SCC mixes such as compressive strength, flexural strength, elastic modulus, resistance to impact load, abrasion resistance, water absorption, chloride ion penetration, freeze-thaw resistance and drying-shrinkage were also performed using appropriate standards. Results indicate that the viscosity of the SCC mixes increased slightly with the increase of RCA incorporation. The compressive strength, flexural strength, elastic modulus, resistance under impact load and abrasion resistance of SCC mixtures decreased with increasing the coarse RCA inclusion up to 100%. In addition, water absorption, chloride-ion penetration and the drying shrinkage of SCC mixtures increased slightly by the incorporation of RCA. On the other hand, the freeze-thaw resistance of SCC mixes decreased gradually by the incorporation of RCA.
