STUDY ON DURABILITY OF CLINKER-FREE CONCRETE WITH A BINDER COMBINING DEHYDRATED SLUDGE POWDER WITH OTHER INDUSTRIAL BY-PRODUCTS ADMIXTURE

Abstract

 Increasing demand on the reduction of CO² emission in the construction industry has required development of new concrete without ordinary Portland cement. Such concrete, e.g., geopolymer, has draw-back in terms of carbonation resistance when applied to reinforced concrete structures. To account for this improvement, the authors focused on clinker-free concrete involving dehydrated sludge powder (DSP) produced from waste ready-mixed concrete, which is returned from construction site to concrete manufacturer without used for construction work.
 In this study, durability of proposed clinker-free concrete with a binder combining DSP with other industrial by-products was studied in terms of carbonation resistance and cracking resistance. As a result, it was confirmed that, at an appropriate water-binder ranges and using DSP with less than about 8,000 cm²/g of specific surface area by 60-80% of binder, the proposed concrete showed equivalent or higher carbonation resistance than that of normal concrete, and when applied to PCa members, showed sufficient cracking resistance under restraint rebars, while free shrinkage strain was 100 to 200 μ larger than that of normal concrete.