Poor Construction Can Lead to Crack Development, Here?s How
A number of factors contribute in the poor construction practices, for example inadequate concrete curing, lack of formwork support, insufficient concrete compaction, or even adding water to concrete in the field can result in the development of crack in plastic and hardened concrete. It is due to such mistakes that leads to concrete being prone to cracking at low tensile stress rather than the design calculations.
It is therefore extremely important for contractors and site engineers to follow the required procedures to be able to avoid poor construction practices. To be able to maintain good construction practices it is important to have the right kind of supervision for construction works and also by hiring skilled labour.
Which kind of poor Construction Practices Can lead to Crack Development in Concrete Elements?
Given below are some poor construction practices which can lead to certain crack type formation:
If you add water to Fresh Concrete on Construction Site
A common mistake which is made is by adding water to concrete at the construction site so as to increase workability, this mistake must be avoided.This result in the reduction of concrete strength and also an increase in drying shrinkage and plastic settlement.
By the end of the process, the shrinkage cracks and plastic settlement cracks starts developing. The shrinkage cracks pattern is isolated or individual in nature and it usually runs in the same direction, whereas that of plastic settlement cracks runs mostly in a diagonal direction.
Increasing Cement Content to Offset Strength Reduction due to Addition of Water to Concrete There will be a raise in temperature differentials between the interior and exterior section of the concrete element with an increase in cement content.
With the increase in cement content there is an increase in both thermal stress and drying shrinkage stress. These stresses are the factors which leads to the cracking in concrete.
Lack of Formwork Support, Inadequate Consolidation, and Incorrect Placement of Construction Joints
There will be an increase in settlement if there is a lack of formwork support, there will also be insufficient supports for the concrete setting.
What incorrect placement of construction joints can do is it can open the joints at points of high stress.
Inadequate Concrete Curing
A reduction in the hydration of cement will take place which will eventually lead to decrease in strength of concrete if inadequate concrete curing takes place.It is due to this reason that concrete cracks develop as a result of self-weight even before it has developed enough strength to support itself.
Insufficient curing can lead to significant amount of problems when cement replacement materials like silica fume, slag, and fly ash are used.
It is important to cure these cementitious materials; else, there will be a development of high drying shrinkage, which will result in excessive concrete tensile strength, therefore, making the crack development inevitable.
Image Courtesy: theconstructor.org
