Concrete and asphalt production and installation has the potential to contaminate stormwater and downstream rivers, lakes, and streams with high concentrations of suspended solids, toxic hydrocarbons, and other chemicals, oils and greases, and heavy metals. In addition, hardened asphalt and concrete can clog and damage stormwater drains and pipes, which can result in localized flooding.
By implementing the proper practices below during concrete and asphalt production, installation, and cleanup, your operation or construction site can help be the solution to stormwater pollution.
- Use stormwater drain covers, filter fabric, silt fences, or secured liners to keep concrete dust, slurry, aggregate, and wash water from entering the stormwater drainage system.
- Concrete and asphalt materials should be kept under cover in a building or silo, vehicle, or in a covered storage pile with secured waterproof cover or awning.
- Place drop cloths or tarps under all concrete and asphalt trucks and equipment when not in use. Use drip pans, drop cloths, or tarps wherever concrete, asphalt and asphalt emulsion chunks and drips are likely, such as beneath extraction points from mixing equipment.
- Place hay bales or other erosion controls downslope of installation areas to capture stormwater runoff containing mortar, cement or asphalt.
- Prevent cement dust from settling onto surfaces where it will contaminate stormwater runoff. Sweep up any settled dust; never hose down.
- Contain and collect the slurry from exposed aggregate washing, where the top layer of unhardened concrete is hosed or scraped off to leave an exposed aggregate or rough finish. Do not wash or allow discharge of concrete slurry or asphalt to a stormwater drain, drainage ditch, or surface water.
- Shovel or vacuum saw-cut slurry. Do not allow slurry to flow across pavement and do not leave on the surface of the pavement.
- Protect newly poured and paved areas from rainfall and stormwater runoff until hardened or cured.
- Avoid overspray of curing compounds. Minimize the drift of chemicals as much as possible by applying the curing compound close to the concrete surface.
- Sealing operations should not be undertaken if rainfall is predicted during the application or curing period.
- Designate a washout area facility for truck and equipment cleaning a minimum of 50 feet away from a stormwater drain, drainage ditch, or surface water that has sufficient volume to completely contain all liquid and waste materials generated during cleaning.
- Discharge all process water from production, pouring and equipment cleaning activities to a sump, process water treatment, recycling system or sanitary sewer system. Never discharge or dump raw, excess or waste materials, slurry, or rinse water to a stormwater drain, drainage ditch, or surface water.
- Appropriately dispose of any solid concrete or asphalt waste. Return leftover materials to the base stockpile or mixer.