Investigation of physical and mechanical properties of roller compacted concretes produced with different aggregates

Roller compacted concrete (RCC) is a construction material which has recently been introduced compared to conventional concrete. Roller compacted concrete is generally used in road and dam construction. RCCs having low water/cement (w/c) ratio are one of the rigid road pavement types. RCC can be quickly opened for use after production and provides economic benefit by the way of being produced with conventional building materials. In the experimental studies, CEM I 42.5 R Portland cement, five different coarse aggregates (dolomite, basalt, marble, two different types of limestone), natural sand and tap water were used. Firstly, compact and loose bulk density, specific gravity, water absorption, Los Angeles abrasion resistance and sieve analysis tests were performed on the aggregate samples used. In order to determine the ideal water/cement ratio, roller compacted concrete specimens of C 30/37 strength class were produced and the w/c ratio of RCC specimens was changed as 0.32, 0.35, 0.38 and 0.41. For all concrete specimens, the slump value was zero in the fresh state. In the studies conducted to determine the ideal water/cement ratio, dolomite aggregate and natural sand were used. In RCC production, the dolomite aggregates of 12-19 mm crushed stone, 4-12 mm crushed stone, 0-4 mm stone powder and 0-4 mm natural sand were mixed in certain proportions. Aggregate mixture was prepared by using 25% (by weight) of each aggregates. The slump value, compressive strength, flexural strength, ultrasonic pulse velocity and modulus of elasticity were determined on RCC specimens having different water/cement ratio. Based on to the test results, it was determined that the highest strength values were obtained with 0.35 water/cement ratio. The water/cement ratio of 0.35 was kept constant in subsequent studies conducted with different types of aggregates. After the water/cement ratio was determined as 0.35, mixtures were prepared with different types of aggregates. Five different aggregates (dolomite, basalt, marble and two different types of limestone), were used as 12-19 mm crushed stone II, 4-12 mm crushed stone I and 0-4 mm stone powder. In addition, each of the different aggregate mixtures were mixed with 0-4 mm natural sand. In order to determine the compressive strengths at the ages of 7 and 28 days, cylindrical specimens with 15 cm diameter and 30 cm height were used. Prismatic specimens with the dimensions of 15 cm×15 cm×75 cm were used to determine flexural strengths at the age of 28 days. Before bending test, ultrasonic pulse velocity and modulus of elasticity values were determined by using 28-day prismatic specimens. Test results of RCC samples produced with different types of aggregates were determined and comparisons were made between the RCC specimens produced.