Concrete mix design containing calcareous tuffs as a partial sand substitution

This paper reports results of the use of calcareous tuff in ordinary concrete as a partial sand substitution. The compressive and tensile strengths, water absorption (total and capillary) and resistance to acid environments of concretes produced with two tuffs using varying percentages (5-35%) are studied. The incorporation of calcareous tuff in concrete requires the use of a superplasticizer to overcome the workability loss resulting from the high fines content in tuffs. High concrete performances have been developed with the use of an optimum of 25% of tuff addition. The increase in compressive strength reaches 33%. However, absorption and chemical resistance were reduced probably due to the absorbing character and calcareous nature of tuffs.