EFFECT OF STORMWATER ON THE MECHANICAL PROPERTIES OF CONCRETE

ABSTRACT

Water is an essential ingredient in concrete making. It is essentially provides medium for binding other concrete constituents together. It equally provides flow ability for the concrete. Without water, irrespective of the quantity, concrete may not achieve its workability or may not be worked with. The quality of the water used in this regards and the constituents are very essential factors which influence the overall performance of the concrete. It has therefore been established by researches that only potable water should be used in making and curing concrete. The reach method was essentially involved in the analysis of the storm water so as to ascertain its compositions and their respective concentrations. Thereafter, the storm water at room temperature was used in making fresh concrete. Workability (slump) test was carried out on the fresh concrete. The same concrete was cast into some cubic and beam concrete specimens. Mechanical test (compression test) was carried out on these cubic samples on 7, 14 and 28days while another mechanical test (flexural test) was carried out on the beam samples on the 28 day of casting. The storm water had high concentration of total suspended solids (3.80mg/l), iron (3.104mg/l), low dissolved oxygen (6.20mg/l), high chemical oxygen demand, high temperature and turbidity (0.115NTU). The storm water influenced the mechanical properties of the concrete due to the constituents of the water (impurities of different kinds) which has made it impure. The workability of the concrete was reduced by 6.93%. The mechanical properties of the concrete such as the compressive strength at 7 days it reduces by 51.2% and at 28 days it reduces by 51% and flexural strengths was equally reduced by 32% as a result of the impurities which was incorporated into it through the impure water.