Concrete Pouring

There are are two things we need to discuss under concrete pouring

Basic techniques need to consider and methods of concrete pouring should be considered. Out of those, firstly we discuss key aspects that shall be kept in mind when concrete is poured.

• Concrete Setting Time : It is required to pay attention to the initial and final setting times during the concrete pouring. In general, the initial setting time of concrete is around 45-60 minutes. However, it can be modified by adding admixtures. Setting time can be tested as mention in the article 6 different cement tests. Setting time can be extended as required by the project and as tested during the trial mixtures.
• Formation of Cold Joints : Cold joints are formed when the concrete is poured into the concrete that has started hardening. Therefore, concrete shall be poured before stating the setting. When a large pour is concreting, a new concrete layer will be poured before starting the setting of the existing layer. It avoids the formation of Cold Joints.
• Pouring Pattern : When there is a large concrete pour to be concreted, a pouring pattern is prepared to plan the sequence of concrete pouring. Based on the planned sequence, concrete will be poured to avoid the formation any cold joints.
• Concrete Compaction : It is required to compact the concrete adequately to achive the required quality and strength. Porker vibrator is used to compact the concrete. The period of vibration shall be as per the thickness and type of the mix. Compaction shall be done unitll the entrapped aired is removed and concrete is compacted adequately.
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• Self Compacting Concrete : In special occations where it is difficult to do the compaction of concrete manually, the self compacting concrete is used. Self comapaction of the concrete is achieved through the mix design. Deep and large foundations, concreting of piling, etc are done with the self compacting concrete.
• Free Fall Height : Different guidelines provide different ranges. In general, it is 3 to 5 feets. Technically, it is advisable as much as possible to avoid free fall of concrete to avoid seggregation.
• Temperature Control : Depending on the size of the pour, it is required to limit the rise of the temperature and control the variation of temperature at the surface of the concrete. Methods of limiting the rise of the temperature of concrete are discussed in a sperate article.
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