Tips to avoid Segregation of Concrete and its Causes
What is the Segregation of Concrete?
It is a process of segregating cement paste and the amount of concrete from each other during placement. This separation can also occur from over vibrating or compaction of concrete where cement paste moves at the top and the concrete somehow settles at the bottom making the structure relevantly weak.
This mainly occurs while transporting and pouring the paste, excessive vibrations and jerks could separate the cement from the concrete. Usage of excessive water in the mixture could result in the segregation of concrete. A concrete paste can only be used within a specific time period. If this Segregation is seen while handling the mixture then it should be again thoroughly mixed before pouring into the structure.
Tips to Avoid Segregation of Concrete
• Make sure that the concrete is properly mixed; the concrete should always be properly mixed at the machine for at least two minutes before placing and handling.
• The concrete paste must immediately pour into the structure.
• Always make sure to check the height from where the concrete is poured into. Avoid pouring concrete paste with a height greater than 1.5 meters.
• Make sure to avoid vibrations while transporting to the construction site.
• Make sure to not use any kind of air-entraining agents.
• Make sure the paste is neither too wet nor too dry, to avoid separation of concrete.
• Before pouring the paste always verify its structural efficiency and durability.
• The framework must be watertight so that no kind of leakage occurs.
• The vibration should only be used if necessary and for the only specific time period.
• Do not use any kind of mechanical vibrators in the concrete paste for too long. This will surely separate the materials from concrete and make the structure comparatively weak.
• If somehow the separation occurs, make sure to mix the cement once more and make it right before putting it into the infrastructure.
Main Causes for Separation of Concrete
Concrete Separation is very much harmful for the duration of that particular structure. While mixing the concrete with the materials always take care of this separation. It mainly occurs when excess water is used in the mixture and also occurs when excess vibration is made while mixing.
Few are the main causes for the separation of concrete:-
• Compromising the mixing procedure and made segregation of materials like fine aggregates and coarse aggregates.
• Compromising while deciding the size of the aggregates and materials.
• Insufficient grading procedure in materials and aggregates.
• Handling the mixture roughly.
• Bad transporting and handling of a concrete mixture.
• Applying excessive vibration.
• The appropriate amount of concrete is not used in the mixture.
• Applying more than an adequate amount of water to the mixture.
• Pouring the concrete mixture with more or less ideal height.
• Worn-out blades are used in the mixing of concrete and poor designing of the mixture.
This separation is very hard to locate, and the measurement is difficult to make to fix the mixture. This measurement is only possible at the time of concrete mixing.
To learn more, watch the following video tutorial.
Video Source: Engineering Motive
This separation can only be noticed through a few tests like slump tests or diffusion within a steam test.