Promising laboratory results suggest a path to greater use of fly ash in concrete, leading to sizable reductions in greenhouse gas emissions, energy use, construction costs and landfill volumes.
Currently fly ash accounts for, on average, about 15% of the binder powders in the ready-made concrete used in the US.
To produce a more green concrete, research is being carried out into new material combinations and procedures that could help the industry use fly ash to routinely replace 40 to 50% of the ordinary portland cement (OPC), the main binding and hardening agent in concrete.
Because of delays in setting times and questions about its strength in the first few days after application green concrete has been a tough sell in large parts of the construction industry, according to researchers from the National Institute of Standards and Technology.
However, researchers from NIST and colleagues from the Federal Highway Administration found that a judicious combination of fine limestone powder can help to put these concerns to rest.
The next research challenge is to test their limestone-enhanced mixtures in the field, where curing conditions can vary.
Statistics collected in the UK show that while the average age of motorcyclists has increased, their safety track record has improved only marginally in recent years. Rather than the pursuit of young tearaways, motorcycling is conducted by mature individuals who are also quite likely to own a car. While statistically they like to live dangerously once in a while, the research suggests they would prefer to get from A to B in one piece and remarkably few claim to be reckless speed addicts.
In fact, human error remains the main cause of death and injury but poor road design and surface condition can be contributory factors. Motorcycling associations have shown widespread concern about these issues and highways authorities across Europe have come under attack from the Federation of European Motorcycling Associations (FEMA). FEMA has even accused engineers and maintenance staff of being unaware of the hazards presented to riders.
In the European Agenda for Motorcycle Safety, FEMA highlights several problem areas which it feels require more attention. These include lack of friction of some asphalt types when wet, poor drainage which increases the risk of aquaplaning and bad kerb design. Bituminous asphalt sealers, potholes and the rutting caused by heavy lorries are also singled out for criticism. The biggest problems are, as might be expected, with older highways.
Specialists within the CEMEX UK technical team are well aware of these issues and point out that good design and construction practice ensures highways are safer for all users, not just motorcyclists.
Roads are created by building up layers of different types of coated stone. Basic construction comprises sub base, base, binder course and the surface or wearing course. The base courses have larger diameter aggregate to help withstanding the heavy loads and to ensure the underlying ground is not subjected to stresses from the traffic. Modern surface course formulations, such as stone mastic asphalt (SMA), are able to resist the rutting often seen - and felt - on the inside carriageway of major roads. The final surface layer can be comparatively thin and formed using sizes and types of aggregate that provide very good grip, even in wet weather, which is imperative for the motorcyclist.
When correctly applied, these thin surfacings - including Viatex and Viapave from CEMEXs Via range - are also resistant to wear, which means fewer cracks or potholes develop and less remedial work is needed between re-surfacing. Historically, it is the remedial overbanding with bitumen used in crack repairs and repairs to joints between running lanes that creates small, smooth or slick areas. These areas can catch out the unwary motorcyclist, especially in the wet. Under some conditions these patches are just as hazardous as the unfilled cracks as this may undermine the motorcycle and its rider.
We are constantly seeking ways to help our customers build more sustainable structures and, in doing so, reduce their-and our-environmental impacts. While concrete's properties make it a good choice for building more energy-efficient structures that need little or no maintenance over their useful lives, we work through our Global Center for Technology and Innovation to develop new and innovative products that contribute to more sustainable built environments and reduce greenhouse gas emissions in the process.
We recently launched our Rizal Green cement, an all-purpose masonry cement that can be used for both masonry works and semi-structural projects such as driveways, fences, and ground-floor slabs for residential construction. The result of more than two years of laboratory and market research, Rizal Green has a patented formulation that reduces CO2 emissions by up to 32% when used as a substitute for ordinary Portland cement in masonry works.
Researchers in Spain have developed a new multilayer concrete that is able to support plant life providing a range of benefits including regulating temperature inside buildings.
The cement and ready mixed concrete industry has bee keen to embrace novel ways of improving the environment and this latest development will be of particular interest.
Developed by researchers at the Polytechnic University of Catalonia, Spain, the new concrete acts as a medium for growth and a construction material.
Created for a Mediterranean climate, the biological concrete is composed of three layers placed on a structural base. The first is a waterproofing layer on top of the structural foundation, which protects against moisture damage.
The next is the biological layer, which supports colonisation of organisms like moss and drought-tolerant vegetation. These acts as an internal microstructure that also aids in water retention.
The final layer is a discontinuous coating with a reverse waterproofing that allows water to seep through and keep it inside the concrete. As well as providing an unusual and attractive way to renovate a home or office, the concrete has applications in air purification and CO2 reduction. It can also absorb solar radiation, helping to regulate temperature inside the building.
US scientists have discovered a new way to make lime cement that's less harmful to the environment.
Researchers at George Washington University have harnessed concentrated solar thermal power as part of a technique that could cut the cost of production and release zero carbon dioxide.
Estimates suggest cement manufacture contributes around 5% of total greenhouse gas emissions: the second single largest source after coal-fuelled power plants.
The new process harnesses concentrated solar thermal power to avoid generating CO2 during the two main stages of the production process.
So far, the team has built a prototype, which proves the process can work and the next stage is to take it to an industrial scale.
However, some industry experts have warned that although the process seemed to be "really good" the localised nature of much cement production, using local limestone rocks, might not encourage its take-up.
Despite this many producers of cement, ready mixed concrete and other aggregates products are constantly looking at new ways to reduce their carbon footprint and wider environmental impact.
Its owners want to make sure that roads are kept safe for everyone who is using them, and companies are taking on a leadership role in that regard.
All cyclists on the road should follow these basic safety rules to lower the risk of being involved in an accident:
1. Always wear a helmet.
Properly-fitted head protection greatly reduces the risk of injury or a fatality. A helmet should fit level on the head, and the pads should be level all the way around. The strap should be comfortably snug without feeling tight.
2. Wear bright clothing to be visible to others on the road.
Other road users include drivers and pedestrians, and it's important to be seen. Wear bright or fluorescent clothing in daylight and low light conditions. Reflective clothing should be worn at night. When traveling by bicycle at night, in the rain, or when the sky is overcast, make a point of using a light. It will make the bicycle much easier to spot.
3. Stay well away from the kerb.
Cyclists should give themselves space on the left and not feel pressured to move close to the kerb if a driver behind them becomes impatient. Moving further into the road means a cyclist will be able to avoid most drain covers and roadside debris. It's also an effective strategy for helping drivers to know when it's safe to pass them.
4. Use hand signals to make intentions clear to other road users.
Use standard bicycle hand signals to clearly indicate turns and stops well in advance. Cyclists should always look over their shoulder before while indicating with one hand what their intention is. It's a good idea to practice these hand signals while off the bike to get familiar with them before venturing out on the road.
5. Make eye contact with drivers.
Be aware of other road users. Make eye contact with drivers as a way to let them know that they have been seen. Cyclists should also make a point of making eye contact with pedestrians who are crossing the road as a way to lower the risk of a collision.