Ready-to-use concrete answers builders' prayers

The Blue Circle ready-to-use concrete range comprises three forms of concrete mix - coarse, fine and multipurpose - enabling the range to fulfil a wide variety of uses. The 40MPa coarse concrete contains a 20mm maximum aggregate size, while the 40MPa fine concrete has a 10mm maximum aggregate size.

Product development

These products were developed in response to customer demand for more easy-to-use products that save time and money - but that also deliver a more consistent quality than can often be achieved by concretes that have to be mixed by the user. The products are 'special' because all three of the concretes have been formulated to meet the highest levels of quality, with the blended mix ensuring that required results are achieved every time.

Containing a mixture of Portland cement, concreting sand and gravel, each of the products conforms to the requirements of BS 5838-1(1). Naturally, the final finish quality of this material will depend upon the operative having the required skills and a familiarity with the material and its application methods.

Sitework

The concretes have a number of requirements for site use:

* they should be used within 45-60 minutes of adding water

* the surface should have a closed texture, without excess of runny cement water when patted with a trowel or the back of a shovel

* overwatering will adversely affect the strength and durability of the set concrete

* concrete should be placed when mixed evenly (without causing segregation)

* ensure that it is well compacted - compaction is important as entrapped air reduces concrete strength.

Curing

Curing is essential to the durability of the concrete. Generally adequate curing is achieved by protecting the concrete from rapid drying out and adverse weather conditions until fully hardened. After placing and finishing, the concrete should be covered with plastic sheeting or wet hessian. It is important to allow the concrete to harden sufficiently (dependent on ambient conditions) before proceeding with further works.

Concluding remarks

Each of the products in the Blue Circle ready-to-use concrete range requires only the addition of water to achieve consistently good results. The elimination of the need for careful measuring and mixing of separate ingredients has proved a strong draw for cost-conscious builders who cannot afford product wastage.