When carrying out the construction of concrete structures, special care must be taken, from the handling of the form to the emptying and subsequent treatment of the concrete, the reason is that, if these processes are not performed properly, several errors can occur. We will see some of them below.
Mistake #1: Honeycombs
Honeycombs are spaces in which concrete does not completely penetrate. Many times it is due to a defective compaction process, little space between the steel bars or a poor mixing design, just to mention a few cases. The presence of honeycombs will affect the durability and resistance of the affected element since it exposes the reinforcing steel to the weather, the reparation of this kind of pattern must be executed by removing the concrete in the affected area and replaced with concrete in a time less than 72 hours, or with specific repair products, for example concrete repair mortars
Mistake #2: Bugholes
Concrete bugholes are present when air bubbles are trapped between the surface of the concrete and the form, They are usually present in vertical elements such as columns and walls.
Its presence may be due to many factors, such as the quality of the mixture (gravel size, fluency of the mixture, etc.), emptying methods or the lack of compaction. They should be considered as a serious error if the width is greater than 1.50 in and its depth exceeds 0,50 in.
Mistake # 3: Bad steel positioning
If an adequate positioning of the steel is not carried out before emptying the concrete, movements of the reinforcement bars can occur, which can significantly affect the capacity of the element. A common case occurs in beams, where the displacement of the longitudinal bars brings reductions in the cover, and it affects its durability.
Mistake #4: Bad localization or dimensioning
Either by a bad localization of a structural member or by a misunderstand of the specifications, an element can present dimensions and/or could be located in a point that does not correspond to the specifications required in blueprints.
Mistake #5: Insufficient curing time
The formation of cracks by retraction in concrete structures is due to the evaporation of water from the concrete mixture. The cause of this problem is subject to the amount of water used in the mixture (as the amount of water increases, the number of cracks by contraction increases), climatic conditions and the curing regime. This problem can be addressed by considering an adequate curing regime and adding an adequate amount of water to the concrete mixture.
Comments