Floor saws provide the best performance when equipped with proper diamond tools.
Early repairs cost-effective
01 April 2003
All roads or airport runways, whether concrete or asphalt, need repairs at some time, with heavy traffic, temperature changes and Alkali-Silica Reactivity (ASR) some of the possible causes of damage.
Early repairs are always cost-effective and can greatly reduce the overall rehabilitation costs, according to Diamant Boart's stone division, which is a part of the US-based company Dimas group.
These repairs require the use of diamond tools to cut and remove the damaged portion, to drill holes to anchor new steel reinforcements or to cut joints in newly- poured concrete surfaces.
Restoring a concrete surface (road or airport runway) through CPR (Concrete Pavement Restoration) is a common repair technique which provides new roughened, skid-resistant surfaces through grinding, and is often a cost-effective alternative to overlays, says the company. CPR extends pavement life, improves ride quality and enhances safety.
Grooving and texturing can also improve some surfaces, in particular to provide better drainage channels for water between tyres and pavements, thus preventing hydroplaning accidents.
To perform these various types of repair, many different types of equipment are used, from conventional floor saws to large grinding or grooving machines. All these machines cut, groove or grind with diamond blades.
Floor saws
There are numerous types of floor saw, from very small to very large. The most common are called 'walk-behind' saws as the operator follows the machine. Power on these machines ranges from 5 to 87 HP, and the engine can be diesel, petrol or electric.
These machines provide the best performance when equipped with proper diamond tools, claims Dimas. Diamond cutting blades can cut through any material, even steel reinforcement, very quickly, accurately and in one single operation.
The size of diamond blade is selected according to the depth of cut to reach: a 350 mm diamond blade, for instance, can cut about 120 mm deep, while a 1,200 mm blade can cut slabs up to 500 mm thick.
The other important factor in floor sawing is the power of the saw. If the power of the engine mounted on the saw plays a big role, the most important factor is the true power that the machine can deliver to the blade shaft holding the diamond blade.
A 57 HP diesel floor saw can deliver power at the blade shaft ranging from 40 to 52 HP, depending on the model, meaning a difference in net power of more than 30 per cent. Not all machines with the same engine necessarily provide the same output or productivity.
Dimas floor saws are designed to provide the optimum power and weight balance for all cutting jobs, in blade capacities ranging from 300 mm to 1,500 mm.
Pavement groovers
In grooving applications, the machines are equipped with a large blade shaft to run a series of blades called 'drums' or 'heads'. The blades are spaced according to different patterns, one for every type of application (airport grooving or bridge deck grooving).
These machines are powered with petrol or diesel engines from 16 HP to 230 HP, are self-propelled and some can even be fitted with a slurry pickup device to leave a clean surface after the grooving job is complete.
All grooving is done with specially-made diamond blades spaced according to the pattern required. The width of grooving varies according to the type of machine, from 200 mm to 550 mm and even 900 mm.
Pavement grinders
These are specially designed to produce a level surface with a corduroy-type texture.
The diamond grinding smoothes faulted joints to an impact-free surface, though it does not affect transverse or longitudinal joints, as with carbide milling. And because it is a very soft operation, it does not create micro fractures in the concrete, which could cause premature pavement deterioration.
Finally diamond grinding improves drainage in wet weather and vehicle directional stability, says Dimas.
Grinders offer cutting head widths up to 900 mm and a grinding head can contain as many as 170 blades. Large road grinders, up to 9 m long, have up to 400 HP diesel motors to drive the blades and collect the slurry.
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