3 Ways Concrete Cancer Begins On a Newly Established Structure
Posted on: 12 September 2016
Concrete cancer (also referred to as concrete spalling) is one of the problems that affect the integrity of a concrete structure. Generally, it refers to the breakaway of the concrete surface at the top of the slab, the edges, facades or soffits. If it is not checked, the progressive spalling exposes the underlying material that is used to support the slab, compromising the strength of the building. During construction, preventing concrete cancer is key to avoiding costly repairs in the future and ensuring that the occupants using the structure will be safe considering its reliable strength. If you are an apprentice in the construction field, here some things that can trigger concrete cancer:
Inadequately Treated Reinforcing Steel
Reinforcing steel used to offer structural support to the concrete structure tightly bonds with the fresh concrete when it heals. This means that any corrosion that occurs on the steel directly affects the concrete around it. Before using the steel bars on the structure, check the packaging to confirm that they made using galvanised, stainless steel that is resistant to rust and corrosion by other chemical elements such as chloride salts.
Structural Steel Compatibility
Even under keen supervision, you can easily make mistakes and oversights as a novice. Concrete cancer can easily begin in areas where the structural steel used in a specific location of the slab is incompatible. For this reason, you should restrain from installing incompatible metals in close proximity, as it compromises the ability of the rebar to stand to the weight of the overlying concrete slab. To add on that, incompatibility of the reinforcing metal can easily create pores in the concrete when it cures. The pores allow water into the slab, initiating corrosion of the rebar. Vertical and horizontal bars in pillars, lintels and beams should be of the same size. In a case where they differ in size, make sure that you consult your supervisor before proceeding with the installation.
Improper Door and Window Installation
You should also pay attention to the perfect fit between the windows, doors and lintels. Poor installation means that the inner lintel structure will be exposed to a host of corrosive elements like water and chloride salts. Seal the window frames and doorframes appropriately with fresh concrete, leaving no holes that will encourage moisture to pass through. Ideally, you should burry the frame a few inches into the lintel structure so that it is sturdy enough to support the door or window when they slam against the frame. This will prevent cracks (which encourage spalling).
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