Efficient Use of Cube Moulds for concrete testing

by Hemant Sharma Digital Marketing Manager

Concrete cubes are made on site in order to ensure that the strength of the concrete is greater than the minimum strength that has been specified. The making, curing and the testing of cubes have to be carried out appropriately since small deviations from the standard procedures may end up leading to compressive strength results that are lower than the true strength of the concrete. For example, for each 1% air entrapped there is likely be a 4 to 5% loss of strength. The procedures for concrete cube making can be found in British Standard (BS) 1881:1983 Testing Concrete as well as Hong Kong Construction Standard (CS 1:1990) Testing Concrete.

The equipment that is used for the making of concrete cubes includes the following - Sample tray, mould for making test cube, spanners, scoop, steel float or trowel, compacting bar, vibrating hammer or vibrating table, Cleaning rags, a bucket or barrow for the transportation of the samples, polythene sheeting, and curing tank.

The role of the cubes comes to play after the concrete sample is remixed. After the sample has been remixed you need to fill the cube moulds and then compact the concrete, either by hand or using vibration. Any air trapped in the concrete will end up reducing the strength of the cube and so the cubes have to be fully compacted. However, you also need to take care not to over compact the concrete since that may lead to the segregation of the aggregates and cement paste in the mix. This might also result in the reduction of the final compressive strength.

While making cubes, certain precautions have to be taken. While finishing off the concrete surface, if the mould is overly full, the excess concrete should not be removed by scraping off the top surface since this would take off the cement paste which has come to the top. It leaves the concrete short of cement. The right way is to use a corner of the trowel and to then dig out a fair sample of the concrete as a whole. Then you can finish the surface by trowelling.

Once the compacting of the cement is finished, it should not be left to stand on the same bench as another specimen which is being compacted, since if it is done, chances are that some vibration will be passed on to the first specimen and cause it to be more compacted than the other. In some extreme cases the re-arranging of some of the particles may result, causing segregation.

It is important to make sure that good quality cube moulds are used. You can buy cube moulds online at affordable prices from several sites online. Bellstone Online is India’s largest store for industrial as well as household products. You can use online sources to buy various industrial products online including cube moulds online with great ease. The prices are affordable and the products are also of good quality.