Slurry generation
How is slurry generated in drilling and sawing activities?
In concrete drilling and sawing activities, water is used for:
- Dust suppression to reduce airborne silica exposure to saw operator and other trades
- Blade core and segment cooling to protect tensioning and balance
- Joint flushing to prevent excess abrasive wear or core undercutting
This water mixes with the concrete residue generated from cutting operations, and the resulting mixture is called slurry.
How can slurry generation be minimized?
Both for environmental reasons and to facilitate its management, operators should always attempt to minimize slurry generation as much as possible. Therefore, choosing a good slurry minimization strategy would be the first step towards its correct management.
Options to achieve slurry minimization are described below:
- Both for environmental reasons and to facilitate its management, operators should always be attempted to minimize slurry generation as much as possible. Reducing the water used.
- Filtering the slurry.
- Treating the slurry with flocculants
What risks does this slurry entail?
Human health risks
The slurry originated from concrete drilling and sawing activities is an irritant and can cause contact dermatitis on the skin due to the alkalinity and abrasiveness of the materials. If it comes into contact with the skin, it may cause serious burns and ulceration. If it comes into contact with the eyes, it may cause serious irritation.
To avoid these risks, protective equipment such as goggles, alkaline-proof gloves, waterproof footwear, and coveralls, should be used. Additionally, a barrier cream to protect the skin from prolonged contact should also be used. However, national and local regulations should always be consulted in order to ensure that workers are provided, as a minimum, with the mandatory PPE.
Additionally, avoid standing or kneeling in slurry. After work is finished, footwear must be washed immediately and any contaminated clothing must be removed. All PPE must also be removed, and hands and arms must be washed with soap and warm water. If a burn occurs, vinegar or low pH hand soaps can be used to neutralize these caustic burns.
Additionally, it should be taken into account that regardless of the hazardous characteristics of the slurry itself, other risks will be present, such as slippery surfaces that create a slip hazard. In this sense, slurry and its eventual spillages should be controlled at the source using either the wet vacuum or suitable containment methods.
Environmental risks
Concrete slurry may include various contaminants such as silica, chromium, cadmium or asbestos. This can be extremely harmful to the environment, representing several risks, both for fauna and flora in the area, and may also pollute water and soil. Such risks will depend on the specific contaminants contained in the slurry.
Moreover, concrete slurry can be highly alkaline and may leach into the ground and contaminate groundwater. If it were to migrate into area lakes or streams via storm drains or overland flow, it could raise the pH of these waters and harm aquatic life. If solids are improperly disposed of, they can clog storm drain pipes and cause flooding, as the slurry will rehydrate and will harden inside drain pipes. The suspended solids in the slurry will ultimately become sediment after evaporation of the slurry water. If not properly disposed of, these sediments can migrate to waters and harm them and the aquatic life in them.
To avoid these environmental risks, slurry must always be handled correctly, and appropriate protective measures taken. This document should be used as a guideline, but one must always take into account the characteristics of the slurry to be handled, the particularities of the area and national and local regulations.
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