توسعه یک بتن بدون فشرده سازی تجاری بدون سنگ آهک و مواد جامد آتشفشانی

Self-compacting concrete (SCC) is a concrete with enhanced fresh properties that allows pouring without external compaction. Its advantages also are extended to good segregation resistance, higher homogeneity, lower permeability, which among others, lead to a product with higher durability. Although the SCC advantageous, up to the begin of this research program, never a SCC composition was been produced and commercialized in the Madeira Island. This paper describes the experimental program carried out on the development of a commercial SCC composition, using the materials currently available in the local market of Madeira Island. Moreover, it aims to contribute to the establishment of a methodology that leads to optimized compositions to satisfy the performance requirements of the commercial SCC compositions. Several SCC mix compositions were tested, studies being initially carried out on pastes and mortars. As limestone filler is not currently available in the local market, the powder content was increased by incorporating fly ash, being the water-to-cement ratio kept low by using a superplascyzer and a plasticyzer. All the aggregates were from volcanic origin; the fine sand was from the ocean and the coarse sand, fine gravel and coarse gravel were crushed. At the end, an optimized SCC composition was validated in real/commercial conditions: it was produced in a ready-mix concrete plant, transported and applied in a real structure wherein self-compacting properties were required due to high reinforcement content. Since no markedly changes were introduced from production up to casting, results were considered satisfactory. Consequently, the concrete plant decided to commercialize the SCC composition in the Madeira Island market.