Quality Control of Concrete

The quality of concrete is influenced by various factors like quality of concrete materials, mixing method, carrying, placing, water-cement proportion etc.

If the volume of concrete is higher, then ready-mix concrete should be used whereas the mixture machine should be used for small quantity concrete. In recent times, producing ready-mix concrete formation in plant is managed digitally. But in construction site, when concrete is formed with mixture machine, it should be controlled by hand.

To maintain the quality of concrete that is mixed with mixture machine, the following points should be taken into consideration :-

Material quality: To develop superior quality concrete, the standard quality material should be used. Therefore, it is suggested to always select best quality materials according to design requirement. Make sure that the aggregates do not contain dust or other foreign material. Choose sharp edge aggregate.

Prior to transfer coarse aggregate into mixture machine, sprinkle water on it. Fresh drinking water should be utilized in concrete mix.

Mixing proportion: To work out the quantity of material, a steel box known as Fera is used. The volume of a Fera is 0.625 cubic feet. It is equivalent to half bag of cement. Assume that the proportion of mix for the concrete 1:1.5:3. So, there will be one bag cement, three fera fine aggregate (sand) and six fera coarse aggregate (stone chips) for a batch.

Also Read: Concrete Testing & Inspection Method

Appoint one person to count the materials of concrete as well as keep the record on a paper and provide into the drum of mixture machine. Find out the required water content for one bag cement.

Mixing: Now turn on the mixture machine. Place one-third of required materials and one-third of water into the drum. Then provide a bag of cement. Then, put the remaining materials and water into the drum. Mix the content correctly. Spin the drum for minimum 120 sec to mix concrete materials perfectly as soon as all the materials are sent to the drum.

Test: To test out the water content in the mix, conduct slump test. If the slump is greater than indicated in the structural notes, lessen slump by mixing additional materials into the mixture drum. To raise the slump, mix water. To learn slump test procedure, go through this article “Usefulness of Slump Test On Concrete”

Concrete cube or cylinder is created to test the concrete compressive strength. If 28 days cylinder test result satisfies the necessary compressive strength then there will be no errors during mixing concrete and the quality of concrete will be fine. If the cube test result doesn’t satisfy the design requirement then the structure should be re-built.