How do we assure the quality of Ready Mix Concrete before using for Construction work ?

Ready Mix Concrete is specialized material in which concrete ingredients are weigh-batch at a plant in a central mixer, before delivery to the construction site. In the case of a centrally mix type, the drum carrying the concrete revolves slowly so as to prevent the mixed concrete from segregation and prevent its stiffening from initial set. This paper represents how one can produce consistent quality of concrete. To make good quality concrete it very necessary to test the raw material of concrete on daily or weekly basis

This article represents the maintenance of quality of Ready Mix Concrete. As the Ready Mix Concrete is widely used all over the world hence consistent quality concrete is necessary. The main objective of this article is that the QA/QC engineer in RMC plant and site civil engineer should have the knowledge of advantages of Ready Mix Concrete over the site mix concrete. This paper will also help to the freshers in maintaining the quality of concrete. The engineer will going to know what will be the steps for making good quality of Ready mix Concrete.

Ready Mixed Concrete is designed by an engineer which is generally known as concrete mix design of a specific grade viz M25, M30 etc.. the design reports shows the proportions of different ingredients(coarse and fine aggregates, cement, water, sometimes fly ash, admixture) of concrete based on the trial mix conducted in lab for a specific grade. Now The batching plant uses the same proportions of the ingredients of concrete( the source of supply of aggregates should be same) for mixing. The batching plant is calibrated and after the mix is prepared , the plant generates a report showing proportions of different constituents of concrete. It should match with the design mix report. This way you have managed a quality control on preparation of concrete mix. After the concrete reaches site you can go for slump test which shows degree of workability of concrete. You also have to take test cubes of the concrete mix to ascertain he strength of concrete mix after 7 days and 28 days.

Precautions to get Good Quality Ready Mix Concrete.

A Check the Quality of River sand / Robo Sand / Rock sand used in concrete.

B Check the Quality & Quantity of 20mm & 20mm down size Stone aggregate.

C Chemical added in concrete to delay the setting time to reach the project sites far from Mixing Plant.

D Chemical added in concrete to increase workability .

E  Quality of Cement used in Concrete. Only OPC 33grade, OPC 43 grade and OPC 53 grade should        be used for all works of High Rise Buildings except flooring PCC and Plastering . Fly Ash based            cement can be used for Flooring ,PCC and Plastering.

F  The distance from project site to Ready Mix Plant.

G  Whenever , receiving the Ready mix concrete, Stop it near the Entry Gate for Checking the      water content through Slump Test and ask one engineer in the mixing plant to verify the           quality of all materials using. Reject the trucks carrying concrete failed in Field Testing.

Onsite Inspection of Ready Mix Concrete

• Every delivery ticket shall be inspected to ensure that a mixture with the correct designation is delivered.
• Inspect delivered concrete; it should be uniform and adequately mixed prior to discharge at the construction site.
• Inspect and monitor water, admixture, and fiber reinforcement addition onsite to make sure that the process performed properly.
• Monitor and examine concrete delivery and placement time to find out whether it completed within the time constraints of the project specifications.