PREDICTION OF FRESH AND HARDENED PROPERTIES OF NORMAL CONCRETE VIA CHOICE OF AGGREGATE SIZES, CONCRETE MIX-RATIOS AND CEMENT

Concrete is the most commonly used building material for building most of the world's buildings and infrastructure. After centuries of usage, it still remains the most widely adopted construction material worldwide. But in many developing nations, the frequent occurrence of building collapse has been mostly ascribed to poor quality concrete. As Nigeria is noted for frequent building collapse, this research reproduces standard concrete practices commonly adopted in Nigerian construction industry with the intent to predict design strength via choice of coarse aggregate sizes ( 12.5 mm, 19 mm, 30 mm and mixed), concrete mix-ratios (1:2:4, 1:3:6, 1:2:3) and ordinary Portland cement types (42.5R and 32.5N). Cement compound's composition tests, fresh property tests and hardened property tests were conducted on samples. Test results from building cites of different Local Government Areas of Lagos State, Nigeria obtained in 2010 are compared with the compressive test results of this research via statistical tools. Results indicate that the fresh properties and hardened properties are influenced in a proportional manner by the sizes of aggregates and that the choices of aggregate sizes, concrete mix-ratios and cement types can be used to predict the fresh and hardened properties of normal concrete. This study also show that poor concrete production is one of the principal cause of frequent building collapse in Nigeria.