![]() ![]() Using as low a water ratio possible in the mix will limit the size of the voids in the cured concrete, minimizing shrinkage. ![]() Covering the surface with plastic will slow the evaporation rate.ĥ. Pouring the concrete in the early AM or late PM hours will prevent excessive heat evaporation at the surface.Ĥ. Misting water over the curing concrete will prevent excessive drying near the surface.ģ. “Control joints” are cuts or joints in the forms or troweling joints that “force” the curing concrete to form larger cracks at pre-arranged places.Ģ. The following will control, but not prevent shrinkage cracking:ġ. These must be planned for and controlled by, e.g., silicone contraction joints between sections of a concrete freeway pavement. ![]() Large expanses of concrete without proper expansion joints and control joints can form larger cracks that result from the net shrinkage of large expanses. Shrinkage cracks are inevitable and do not seriously affect the strength of properly formed and reinforced concrete. The drying and shrinking process happens faster at the surface than underneath, so the result is cracking, which is more severe and noticeable at the surface of curing concrete.Īlthough they are barely visible at the surface, they do also extend under the surface. As the water is used up chemically by the curing process, and by evaporation, it leaves behind voids (empty space between the solid particles) which allow those particles to move closer together. Concrete is made with a large percentage of water. These occur invariably as concrete cures, but more noticeably if it cures rapidly. Kinds of Non-Structural Cracks Shrinkage cracking A simple example would be a weld that cracks without any applied stresses from loads because of “leftover” or residual stresses due to uneven heating of the weld and the members it joins. Non-structural cracks are generally caused by stresses that are induced internally. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |