Self-builders and keen DIYers are beginning to recognise the benefits of using ready mixed concrete rather than dealing with the mess and inconvenience of mixing their own concrete on site. But is ready mix really the best solution, and what are the alternatives?
Here at North West Ready Mix we have experience supplying various types of concrete to commercial and domestic customers, so we’re well placed to explain the pros and cons.
Ready mixed concrete
Ready-mix or ready mixed concrete is concrete that’s been manufactured in a batch plant to the customer’s specification before being transported to site, usually in a barrel truck or in-transit mixer.
As the concrete is supplied to specification, with admixture often included, it can’t be used on another site and as such, any excess that goes unused has to be disposed of. This means that the customer can pay for too much concrete and then pay again to dispose of the excess product, which can eat into construction budgets and has a negative impact on the environment.
Any delays in transportation to site can result in the premature stiffening of the product, which may lead to a low quality pour and in some cases, require the disposal of the entire batch.
Volumetric concrete
A volumetric concrete mixer has separate compartments for each of the constituent materials required to produce concrete: sand, stone, cement and water. This means that the exact quantity of concrete required can be mixed on site to the customer’s specification, with little to no waste, so no additional cost to the customer or the environment. Admixture can be incorporated into the mix where appropriate.
Another obvious benefit to the use of a volumetric mixer is that different spec concrete can be used throughout the site if necessary. And there should be no concerns about delays in transporting the concrete to site.
On small sites, for example a garage or kitchen extension footing pour, volumetric mixers can supply as little as just 1 cube (1m3) of concrete. For large-scale sites, if a company operates multiple volumetric mixers it’s possible to provide a continuous pour, and high capacity concrete pumping is also available if a pump is connected to the mixer.
Environmental considerations
We already touched on the impact of waste concrete on the environment, but there are other environmental issues to consider. For example, a typical volumetric mixer uses on average 35-45 litres of water, compared to approximately 900 litres used by a traditional barrel truck. And a volumetric truck doesn’t have to idle while waiting to mix or pour concrete, whereas a barrel truck must idle to keep the barrel rotating in order to prevent premature stiffening of the product.
Given that the pros of using a mix on site solution for smaller projects far outweigh any disadvantages, we would recommend this cost-effective approach over ready mixed concrete, where waste can be a significant burden on budgets and the environment.
