REPAIRING CONCRETE DAMAGED BY PRESSURE WASHERS & HEAVY DUTY CLEANING CHEMICALS
It might not seem like it at first glance but car wash facilities can be extremely aggressive environments for concrete.
Concrete slabs in car wash yards are frequently blasted with high pressure, high velocity water from hoses and pressure washers. Although pressure washers are often used to remove dirt from concrete surfaces, they also cause damage. Abrasion takes away the top particles each time the surface is blasted, so flakes, pits and pot holes gradually begin to form. The more often the concrete is power washed, the more this happens – and in car washes this happens very frequently.
Concrete is porous, allowing water to permeate in to the outer surface. In car washes the wet-dry cycles are incredibly frequent. In cold temperatures the water in the slab freezes and expands as it turns to ice, breaking off concrete particles as it does so. Because the concrete in a car wash experiences more wet-dry cycles it will also experience more freeze-thaw cycles than say a concrete forecourt, it by default suffers more surface damage too.
The products used to clean vehicles car washes can also erode the surface of the concrete by chemical attack. The more the concrete loses its top surface and becomes pitted and undulating the greater the exposed surface area becomes – giving both the chemicals and water more surface to attack.
There are a number of solutions to repair and protect concrete in car washes. Before any damage occurs to the concrete surfaces they can be treated with a protective coating to resist both water and chemical attack.
It is important to know the type and concentrations of chemicals in the cleaning products as this will effect product selection.
A single part, use straight from the tin, floor paint is the quickest, simplest and cheapest way to protect concrete surfaces. The drawbacks are that it won’t last very long – it has only a limited resistant to the abrasion caused by vehicular traffic, power washing and the clean chemicals. This is only an option if you don’t mind preparing and reapplying paint to concrete every few months.
HIGH BUILD COATINGS
High-build coatings provide greater chemical resistance and are more durable to wear from vehicles. For protection against discolouration in sunlight the coating should be resistant to UV.
Resin screeds laid at 6-9mm provide excellent chemical resistant and durability. Again to avoid discolouration in sunlight it must be a UV resistant resin.
SELF-LEVELLING WEARING SURFACES
Heavy duty levelling and resurfacing compounds can be laid at 2-20mm and can either be applied to good concrete to act as a protective coating from the outset. Or it can be applied to damaged concrete to rectify level differences, spalling and/or pitting; it then also protect the concrete below from thereon in. The product must be suitable for outdoor use and able to withstand vehicular traffic, water, frost and car wash cleaning chemicals.