Sustainability Flashcards
What does
Economic
Environmental
Social
Sustainability cover?
Economic sustainability involves life cycle costs (design, construction, operation, maintenance, repairs, reconstruction) and efficiency of construction and operation of pavement. Efficiency means eliminating things that are unnecessary.
Environmental sustainability includes minimising impact to environment. This includes extracting materials faster than they are generated, producing waste faster that it can be absorbed and disrupting equilibrium of ecosystems.
Consider pollution, wildlife habitat, and preventing aborption of water.
Emission of gases and heat during asphalt production.
Consider increased use of renewable resources
Build with recycled materials
Find alternative uses instead of disposing materials as waste
Social Value of projects:
Pavements must have a useful function and a purpose
Help people meet needs, or a roads that produce fewer accidents and improve safety and help people travel more efficienctly which in turn reduces burden on remaining infrastructure as well as lowering social and economic costs due to injuries. (improve mobility, cycleway, pedestrians active travel, physical connections. allow access to many users and modes of transporation beyond cars and trucks . However drawbacks such as noise levels must be mitigated. Noise walls, speed bumps are enhancements. Open graded friction courses improve traction and reduce noise. Re-vegitation of slops prevent erosion and keeps pavement clear and safe from slides.
What are four methods of making pavements more sustainable? And explain why?
1) Reclaimed Asphalt Pavement (RAP)- recycling asphalt for new pavements. Existing surface can be cold milled/ milled and used for virgin aggreagate in new mix and liquid binder can be recovered and re-used. This reduces need for raw materials and cuts back on waste production.
2) perpetual pavement- pavement designed so that it never needs complete replacement and its use can always be extended by rehabilitation. This is done by constructing the pavement in layers to limit distresses to surface layer. Rehabilitation involves milling the surface and placing a new overlay. This saves cost in construction work and materials. Lower material usage and emissions help environmental sustainability. And millings can be recycled as RAP.
3) Warm Mix Asphalt WMA- this is a method of producting asphalt at lower temps compared to traditional hot mix asphalt. This is by using foaming asphalt binder or additives to improve bonding. It uses less fuel to achieve temps and has less demand for fossil fuels and lower fuel costs & less harmful emissions and more comfortable working environment for crews as less fumes.
4) and porous/ permeable/ pervious pavement- designed to let water through. Done by open graded asphalt pavement over a layer called a stone recharge bed and minimally compacted subgrade. This reduces flooding and doesn’t harm wetlands as much and doesn’t affect sources of drinking water. and it reduces pollutants picked up on water surface on surface run off as it’s going down into the pavement
