Investigating the effect of selected volume batching means on the Mechanical Properties of Concrete

Abstract

Batching of concrete materials can be done either by volume or by mass. However, in many developing countries inclusive of Uganda, many researchers have reported that volume batching is the most commonly used method during concrete production with means such as gauge boxes, wheelbarrows, and half-cut jerrycans, among others being used despite the vast caution against it. This research investigated the effect of volume batching means on the mechanical properties of concrete and thereafter, the most effective means were recommended. The mechanical properties of concrete studied included workability, compressive strength, and flexural strength. The volume batching means studied were the gauge box, wheelbarrow, and half-cut 20litre jerrycan. Concrete produced using all the volume batching means was mixed using the same water-cement ratio of 0.60. Concrete samples that were cast for the study were; cube samples of 150x150mm and beams of size 150x150mm and length of 400mm for each. The tests that were carried out during the study were the slump test, compressive strength test and flexural strength test. It was found that indeed, the means used during volume batching does have an effect on the mechanical properties of concrete. All mechanical properties of concrete investigated varied with the volume batching means used during production. Results from all the investigations made showed that the concrete batched by the gauge box had the best mechanical properties, followed by the wheelbarrow with moderate quality, and then the concrete batched by the half-cut jerrycan had the worst mechanical properties. It was therefore recommended that in case volume batching is employed during concrete production, the gauge box should be used. The wheelbarrow can be used as an alternative but it should be limited to minor concrete works. The half-cut jerrycan on the other hand, should be highly discouraged.