Admixtures on Performance and Economics of Recycled Aggregate Concrete
V. Corinaldesi and G. Moriconi
Appears on pages(s):
building rubble; chemical admixture; concrete costs; envi-ronmental
advantages; mineral admixture; recycled aggregate con-crete
Concrete specimens were manufactured by completely replacing natural aggregates with recycled aggregates from a crushing plant in which rubble from building demolition was ground. Various concrete was prepared by using silica fume or fly ash as a partial fine aggregate replacement and by using an acrylic polymer based superplasticizer to achieve the prefixed workability. Three types of recycled aggregate concrete were manufactured with the same water/cement (0.40) and the same fresh workability (fluid consistency). A reference concrete was also prepared by using natural aggregates with the same particle size distribution as the recycled aggregate, and having a water/cement of 0.56 and a similar fluid consistency. The results obtained show that because of mineral addition and W/C reduction, recycled aggregates can be used instead of natural aggregates since concretes with similar compressive strength can be obtained. The use of the recycled aggregates with fly ash replacements also has significant cost and environmental advantages over ordinary concrete.