In any construction project, there is likely to be concrete wastage – a small percentage of the concrete that gets dropped on the floor, left on the mixing bed or left unused. These small amounts of concrete wastage still add up to some loss in costs for the contractor, so they need to be minimised as much as possible.
Around three to five percent of concrete is usually wasted on an average building project. However, even this amount can increase the cost of the project. Proper planning and taking extra care when mixing and working with concrete are the best ways to reduce wastage on-site. However, there are several other steps that contractors can take to minimise concrete loss.
Pre-pour checks can minimise concrete wastage
Firstly, pre-pour concrete checks should be conducted to ensure that the site is prepared properly. There should be minimal travel distance between the site where concrete is mixed and where it will be poured. This will reduce the chances of spillage on the way to the pour site.
Concrete pour cards should be completed as this will inform workers exactly how much concrete needs to be prepared for the job. These cards will ensure that no extra concrete is mixed, which will go to waste when it is not needed for the project. Contractors need to calculate the volume of concrete needed, as accurately as possible, before the pour takes place.
Steps to take during the pour
While the concrete is being poured, contractors should aim to match the speed of mixing with the speed of pouring. In other words, new concrete batches should be mixed just in time for use, when the old batch runs out. This will reduce any waiting time between pours, where the concrete will start to set before it is used.
Towards the end of the concrete pour, the contractors who are mixing the batches need to be informed. This will allow them to stop mixing new concrete in time and to avoid extra concrete supply that will go to waste. Communication is a key factor in minimising concrete wastage during the pour.
In situations where unexpected delays and issues stop the concrete pour, the supervisor needs to have a plan for the concrete being mixed. Using mechanical mixers can help in these situations as they continue to churn the mix and prevent it from setting. Manually mixing concrete can be affected by delays in a pour.
Contractors should always aim to use any leftover concrete elsewhere on the site in order to avoid wastage. This is why planning, communication and timing are such important factors on any construction project. Steps need to be taken before and during a concrete pour to minimise the wastage on-site.
LafargeHolcim is a leading building materials and solutions company that has been operating in international markets for decades. We produce cement and aggregates for construction projects, ranging from small affordable housing developments to large-scale infrastructure projects such as high-rise buildings, dams and bridges.
LafargeHolcim Tanzania has been supplying the country and neighbouring countries with our world-class Tembo cement brand for over 30 years. Our head office and fully-integrated plant are located in Mbeya, Southwest Tanzania.
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