Measures taken to mitigate environmental impacts while concreting for construction
With the large scale construction activities going on everywhere, the potential environmental impact in cement works for concreting are to taken care of. Air quality, noise nuisance, water quality and visual impact induced by concrete batching plant operated for construction working.
A. Fresh concrete and cement-related mortars are toxic to marine life. Therefore, Concrete run-off from washing or leaking equipment or from disposing of these materials to the street gutters and stormwater drains eventually finds its way into waterways, which has the potential to cause pollution. It not only does serious environmental degradation, but also against law.
Concrete run-off blocks stormwater drains, pollutes our creeks, lakes and rivers and has a major impact on water quality, aquatic plants and animals. Appropriate measures must be taken to control concrete run-off.
Understanding few environmental best management practices should significantly reduce the likelihood of pollution from typical day-to-day concreting activities; some of these are:
(a) Establishing a concrete wash-down area on-site. (b) The wash-down area must be located with appropriate sediment controls. These should be inspected and maintained regularly and be repaired or replaced as necessary; (c) minimize the amount of wash-down water generated, scrape excess concrete off the equipment before it is washed; (d) Place excess concrete into a site receptacle designated for concrete and masonry; (e) A high pressure, low volume water spray nozzle conserves water and reduces maintenance of sediment controls; (f) Wash-down water is best managed by draining it into a container, allowing the water to stand until the solid particles settle at the bottom. After adjusting the pH of the water to neutral, it can then be siphoned off and reused, and the residue in the bottom can be allowed to set, then recycled with other excess concrete and masonry material; (g) No wash-down water may be disposed of to the sewerage system without prior agreement of the local water authority; (h) Do not allow equipment wash-down water to flow directly into a stormwater drain or system.
B. Ensure that concrete washed from trucks and mixer units on site is contained and does not leave the site or enter the stormwater system.
C. For modern commercial skyscraper building development projects, the works involved piling, concreting and eventually superstructure construction. Many, being in the heart of busiest commercial central district, noise arising from the concreting work were the major concern. Measures to be adopted: (a) Quieter Method - A purposely-built acoustic enclosure was built to screen the operation of concrete pump and the concrete lorry mixer. The mixer is a Specified Powered Mechanical Equipment which demands a more stringent acceptable noise level; (b) No concreting work was allowed beyond 11 p.m.; (c) Administration - To ensure good communication, the contractor was required to submit a 48-hour-advance notification before commencement of concreting work of those identified bore piles and diaphragm walls necessitating major concrete pour; (d) With the incorporation of the purpose-built acoustic enclosure, the construction noise from the subject site was reduced to a level below the relevant Acceptable Noise Level.
D. General precautions: All such rules and legislations relevant to reduction of impact of concreting are to be adhered to by all the personnel engaged at the job site. Proper training procedures are also to be followed in order to impart training for adoption of all the procedure laid down.