Assessment of cement- sand mortar under direct compressive load

An experimental investigation has been carried out to study the effect of variation of compressive load on mortar specimens. Ordinary portland cement and river sand as fine aggregate was mixed with water/cement ratio of 0.45. Loads of 0, 30, 50 and 70% of compressive strength at 7 days were applied to the samples of age 7 days separately and released the load immediately. At higher loading range, cracks of up to 2 mm have been noticed on the surface of the samples. The stressed samples were tested for percentage apparent porosity and water absorption which showed increase in their values with the higher load application. Compressive strength and ultrasonic pulse velocity of the stressed samples confirm that the quality of concrete deteriorate with load application.