Concrete is a mixture of water, sand, stones and cement. It hardens to a stone like mass within a few days. Concrete  is highly strong and durable with a life span of about 50yrs.

Concrete is a major constituent of modern building structures. Many houses, roads,bridges, skyscrapers are constructed using concrete.

Grade of Concrete

Grade of concrete refers to the strength and quality of concrete. The grade of concrete typically depends on;

1. The type  of constituent  materials used for making the concrete.
2. Mixing ratio of the materials; the amount of cement being a very important factor.

Concrete grades are usually designated with the letter C followed by its typical strength at 28 days.

For instance, a Concrete grade mix of C7.5 means that it has a strength of 7.5 N/mm2 after 28days. This type of concrete is only useful for light weight loading.

On the other hand a concrete grade mix of 25N/mm2 is a heavy duty concrete containing dense aggregate.  This grade of concrete is what is acceptable for reinforced concrete works. The mix for this grade is 1 part  of cement to 2 parts of fine aggregates (sand) to 4 parts of coarse (stone) aggregates. Mix ratio 1:2:4

Cement is the binding agent that binds sand or sand and rock to form a  very strong concrete mass within a few days. Without cement, there is no concrete. Without cement there is no mortar.

Concrete has made it possible to build structures never before possible. Without cement to make the concrete, it would have been impossible.

Small graded rock particles, sand, cement and water are mixed together in certain proportions to make concrete. The water interacts with cement to bind the mixture into a solid mass within a few days.

There are different types of cement including;

Ordinary Portland cement,

Rapid hardening cement,

Low heat cement,

White ordinary portland cement… and so on. The common thing all these types of cement do is to Bind together when water is added.

The ordinary Portland cement is the most produced type of cement. It is suitable for all kinds of concrete and mortar works.

Cement is usually supplied in 50kg and 25kg bags. It has a volume of 0.033 cubic meter and density of 1440kg per cubic meter. 

Hollow sandcrete blocks are the common units for wall construction in West Africa and many parts of the world. The blocks are designed hollow to make them easier to carry. The hollowness of the blocks also enable easier placement of conduit pipes and other accessories inside the wall.

Sandcrete hollow blocks are made of cement, sand and water in controlled proportions. 

A block making machine moulds the block into shape, then compresses and compacts it before it is left to dry in the sun.

Sandcrete blocks can be used for the construction of load or non load bearing walls. They also have very good fire resistance properties. 

The blocks are produced in various sizes. The 225mm( thick) by 225mm (height) by 450mm ( length) is used for external wall construction, while the 150mm(thick) by 225mm ( height) by 450mm ( length) is used for internal wall partitions.