Evaluation of quartz sand deposits for concretes made with portland cement

Abstract

The uniformity coefficient and the fineness modulus are the two grain size parameters of a sand sample that as a great influnce on the concrete strength. High compressive strength results on sand samples with high uniformity coefficient and with high fineness modulus are found. In these sense, this article evaluated the grain size properties of three commercial deposits of sand at Parana River in the Alto Paraiso city. To evaluate the influence the three sand sample on the concrete properties specimens that are 100 mm of diameter, 200 mm of high and class of resistande of 20 MPa were made. A compressive strength test and a slump test were performed to evaluated this influence. The three sand sample have a 28 days compressive strength higher than 26,6 MPa (minimum dosage strength). The compressive strength of sample 3 is 32 % higher than sample 1 and 12 % higher than sample 2. It begins because sample 3 with higher uniformity coefficient as a most efficient packing arrengement, consequently lower is the air índex as a higher compressive strength. As higher is fineness modulus lower is the grains surface, lower is the cement past amount and consequently higher is the resistance.