Replacement Of River Sand With Crushed Sand Stone In Concrete Production

Abstract

Sand is a vital ingredient in making two most used construction materials: cement concrete and mortar. Traditionally River sand, which is formed by natural weathering of rocks over many years, is preferred as fine aggregate. The economic development fueling the growth of infrastructure and housing generates huge demand for building materials like sand. Crushed sand is a term used for aggregate materials less than 4.75mm and which are processed from crushed rock, sand stone or gravel. The indiscriminate mining of sand from riverbeds is posing a serious threat to environment such as erosion of riverbed and banks, triggering landslides, loss of vegetation on the bank of rivers, lowering the underground water table etc. Therefore, use of scientifically produced Crushed Sand as an alternative to river sand is the need of the hour and will provide a long-term solution to our Country’s Construction Industry. This research was, therefore, conducted to study the influence that crushed sand stone have in compressive strength of concrete of different mix compositions and to assess the prospects of using crushed sand stone as replacement of natural sand in Ethiopia. Initially, river sand and crushed sand stone samples to be used in the concrete mixes were collected and their physical properties were studied. Crushed sandstone sample was collected from the Ambo Town about 125 km west of Addis Ababa. 81 concrete test cubes were casted having different concrete mix proportions for both river and crushed sand stone (i.e. 100% RS + 0% CSS, 50%RS + 50% CSS and 0%RS +100%CSS) for C-20, C-25 & C-30 compressive strength. The properties of these mixes have then been assessed both at the fresh and hardened state. The test results showed that the crushed sandstone with 50%CSS+ 50%RS proportion was capable of achieving a similar compressive strength as the river sand control mix.