Concrete is the most widely used construction material in the Singapore. Not only does it simulate the properties of rock but it is easy to use, readily available and relatively cheap. It is a blend of aggregates combined and bound together. Generally, the key components include natural sand and gravel or crushed rock bound together by a hydraulic binder such as Portland cement. The components remain relatively inert until they are activated by water forming a dense semi homogenous mass.
Despite its strength and durability, concrete is prone to some common problems. Many are known (and referenced in our Concrete repair thesaurus) but this blog focusses on some of the less known terms and practices we commonly employ at Remedial building Services. We will be building this guide over time so watch out for our second instalment.
Concrete crack filling
Cracked concrete is one of the most common issues in structural repair. As concrete cures, the heat in it pushes out the water causing the mass to shrink. Overtime, a poorly laid slab may crack outside of intentionally placed joints causing structural issues, waterproofing issues and more. When this happens, dependent on the severity, we may address this problem by removing the entire slab and treating the steel, or if only a minor issue, use a concrete crack filler; a polymer-based material which seals the area and prohibits any water penetration. This is often referred to as crack stitching.
Trowel-grade light coat
Scaling occurs when parts of concrete surface start to flake or chip away. This is due to water seepage, freeze-thaw, poor concrete finishing, or a weak surface due to lack of curing. Typically, this will start in one area, but if left untreated, it can expand to other areas.
As necessary, we may use a trowel-grade light coat to remedy the issue. This is generally a fast setting trowel grade, polymer-modified cement based concrete which is applied by hand to the affected area.
This is a discoloration that usually occurs due to weather, material exposure, even curing time. Concrete stains are a mixture of water, hydrochloric acid (which can present due to water leaching into the slab and reacting with the steel), and acid-soluble metallic salts. Because of concrete’s porous qualities, they penetrate and react chemically in the concrete. Concrete stains then become a permanent part of the concrete and ultimately an eye sore. Fortunately, there are a variety of ways to repair this issue.
One method would be to use a concrete cleaner. These products are meant to give your concrete a better look and can be all you need to get your concrete looking normal. They’re known for their durability and long-lasting colour because concrete stains will not fade, chip, or peel off. The second method is utilised when the underlying issues are too large to ignore and indicate large scale and potential structural issues. In this instance we will remove all affected concrete to expose the cause before treating it.
Another concrete repair option for building owners with cracked, discoloured or imperfect old concrete is resurfacing. Polymer overlays come in a variety of colours and patterns and can restore your structure to a near new condition.
Source – Remedial Australia