In construction — especially concrete construction projects — concrete slabs would crack if the concrete is poured continuously without breaks. The reason is that concrete tends to expand and contract due to thermal ranges and variations. It is for this reason that engineers use metal keys between concrete slabs because the keys help to control shrinkage, cracking and differential movement. However, it is essential to choose the right keys because a mistake in your selection can compromise the structural integrity of the building. This article highlights the critical features of high-quality concrete keys. Read on to find out more:
One of the essential attributes that make a high-quality construction key is a galvanised coating. Most contractors believe that, since metal keys are sandwiched between concrete slabs, there is no way that moisture can reach the metal keys and initiate rusting. However, nothing could be further from the truth because corrosion can begin immediately once the metal keys are in place and covered with wet concrete. Therefore, if the metal keys you use are not adequately galvanised, the chances of rusting increase as the concrete cures. Over time, rusted keys deteriorate and affect the expansion and contraction of concrete which weakens a structure. Therefore, ensure that you only use metal keys that have a galvanised coating.
When metal keys are put in place and the concrete is ready for pouring, the keys must remain straight at all times. However, due to the heavy weight of wet cement, ordinary metal keys can bulk or bend, thereby compromising on functionality. Consequently, a concrete slab might end up with crooked joints. High-quality metal keys are equipped with stiffening ribs at the top and bottom sides. The ribs provide the metal keys with extra support for straight joints even as workers pour concrete onto the slab. As you shop for metal keys, ensure you select the type of key with ribbed ends.
Wedge Fixing Mechanism
One thing about concrete slabs is that builders have very little time to install and accurately adjust their heights. The task is made much more difficult with metal keys that come in different designs. Notably, some metal keys are designed in such a way that they allow for fast and accurate height adjustment. It is all thanks to the wedge shape, which ensures that construction workers can always set up the slabs quickly at the correct heights.