An Overview of Effect of Delay in Concreting on Strength of Concrete
Publication Date : 04/04/2019
It is difficult to cast the whole structure monolithically if the concrete elements are large size; there are some limitations to the availability of formwork, concrete workers or supply of the fresh concrete. In such cases, it becomes necessary to perform structure elements in two or more stages, which leads to formation joints Cold joint is one of concreting problem due to delay of casting the second layer. Therefore, the target in this work is to study the effect of delay in time period when casting the second layer of concrete after 3, 6, 12 and 18 hour Experimental work was performed at laboratory to investigate the mechanical properties of concrete (compressive strength, splitting tensile strength and flexural strength, permeability test). The results were investigated and it indicates that, in case of delaying in the time period for casting the second layer, there is a great effect on the mechanical properties of concrete. This study gives strength data simulating such improper casting sequences. To scope this problem related to improper casting sequence, which ultimately results in formation of cold joints, we have used cement slurry and high grade concrete to prove this we conducted experiments. The study aims for identifying such a time lag after that the required target strength may be achieved even after delay in casting. To identify the meeting planes of two interface layers which has lesser effect on compressive strength. Use of Bonding Agent (SBR Latex) for improves executed construction joints provide limits for successive concrete placements, without adversely affecting on structure.
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