How to get rid of common issues in concreting
In order to develop concrete with superior quality, it is required to resolve various issues which are generally happened throughout concreting because of incorrect mixing, arrangement and execution. There are other issues which occur because of climatic changes and other reasons. These issues may significantly the strength and longevity of concrete. So, it is recommended to have clear ideas on the general issues of concreting. Given below, the detailed lists of general issues :
Segregation, Bleeding, Shrinkage cracking, Dusting, Laitance and Scaling etc.
Segregation: Segregation of concrete means parting of components of concrete from each other. In concrete technology, segregation comes in two different types. First of all, the coarse aggregate is parted from the primary mass of concrete in its plastic state. Then, the grout (cement+paste) is parted from the mix. The second one usually happens if a concrete is excessively wet. The segregation leads to honey comb, scaling, laitance, porous layers and bond failure at construction joint etc. in concrete. To get rid of segregation, the following actions are recommended :-
Concrete mix-design should be done in perfect manner
Mixing concrete ingredients in a perfect way
Keeping water-cement ratio perfect
At the time of placing, the concrete should not be dropped from a high distance
Concrete should not be vibrated excessively
Bleeding: when concrete starts to organize the mixing, water emerges out from the concrete and evaporates. If evaporation rate of water is inadequate, then water exists on the concrete surface. It is known as bleeding of concrete. Normal Bleeding is associated with concrete hardening process. But additional bleeding may damage the concrete. It lowers the bond among reinforcement & concrete and as well as concrete particles with cement paste. Consequently, it lowers the strength and longevity of hardened concrete. In order to get rid of the bleeding issue, the following methods can be applied.
Keeping the perfect water-cement ratio
Water reducing admixture should be used with concrete mix
Well graded fine aggregates should be applied