Properties of concrete modified with mineral additives

Abstract

Concrete is the most widely used building material that is obtained by curing the mixture prepared from coarse and fine aggregates, cement and water. The properties of concrete depend on the quality and properties of the aggregates, w/c ratio, the uniformity of compression of the mix. Compressive strength of concrete is one of the most important properties. The present paper analyses the effect of mineral additive content on the properties of concrete. Materials used for the test: Portland cement CEM I 42.5 R, 0/4 fraction sand, 4/16 fraction gravel, mineral additive, polycarboxylatether based superplasticizer and tap water. Concrete mixes of 9 compositions were made by adding 0%, 2.5%, 5%, 7.5% and 10% of mineral additives by weight of cement. The tests revealed that the addition of mineral additives up to 10% increases the compressive strength of concrete. According to the test findings the compressive strength of hardened cement paste containing 10% of mineral additives increased 0.99% compared to the control mix. After 7 and 28 days of curing the ultrasonic pulse velocity in specimens with mineral additives increased 2.6% and 4.1% respectively. With the increase of mineral additives content up to 10%, water absorption of concrete reduces and the predicted freeze-thaw resistance increases.