Mix-design and properties of self-compacting concrete made with calcareous tuff

Abstract

This paper focuses on the possibility of using calcareous tuff (CT) in self-compacting concrete (SCC) production. In concrete mixtures, CT is used as sand and its fines as partial cement replacement. Mixtures are prepared with three different sand/mortar ratios (S/M) of 0.40, 0.45 and 0.50 with a varying superplasticiser content (SP). Cement was substituted by fines of calcareous tuff (CTF) with percentages of 0, 5, 10, 15, 20, 25 and 30% for S/M ratios of 0.40 and 0.45 with a varying SP dosage up to the superplasticiser saturation dosage (SSD). The filling, passing ability and segregation resistance tests are used to assess the fresh properties of SCC. The compressive strength of SCC was also determined at 3, 7, 28 and 56 days. The results show that the use of CT improves the flowability and stability of both SCM and SCC. SCC mixtures made with CT satisfy the specifications and guidelines for SCC production. The maximum strength obtained at 28 days was with mixtures SCC incorporating 10% of CTF, which revealed clearly the good adhesion between CT and cement matrix. Finally, CT constitutes a good local eco-material, abundantly available, for the SCC design.