abstract : Crushed rock aggregate is commonly used as coarse aggregate in concrete and asphalt production Fine aggregate could also be produced from crushed rock and it is one of the suitable materials identified for use on alternative to river sand. This material usually has a high content of fines associated with clay size particles considered to be harmful in a concrete. However, if properly controlled, the fines in crush rock aggregate could be used to advantage in improving the strength of concrete produced or in reducing the cement content.
ืNRBO test results show poor grading of coarse aggregate due to inefficient process control and the lack of application of standards. The need to implement standards is discussed.