Recycled Concrete Slab gains significance as it protects geological resources

Much of the U.S. research focused on using crushed, hardened concrete as an aggregate in fresh concrete has been in road paving. Work on this subject began with a major endeavor in the 1980s in Minnesota. Sorry to say, the majority of the research focused on using recycled concrete aggregate (RCA) as a base material to the pavement.

But in other locations of the globe, many recognize RCA as a important aggregate resource when correctly intregated into the mix design procedure. For example, Japan has used RCA for more than 20 years in structural concrete applications.

RCA can be used in effect in structural concrete. Dr. A. Ghani Razaqpur, a professor and chair of the Civil Engineering Department at McMaster University in Hamilton, Ontario, gave a presentation at the 2008 Concrete Technology Forum, sponsored by NRMCA in May in Denver. Razaqpur disputes the belief that concrete (plain or reinforced) prepared with RCA has inherently inferior short- and long-term properties. He supported his assertion by highlighting the results enclosed in the essay, "The Key to the Design and Production of High Quality Structural-Grade Recycled Aggregate Concrete."

Razaqpur described how his team examined 14 different mix designs using RCA. They examined fresh and hardened components (slump, fresh and hardened density, elastic modulus, compressive strength, stress-strain correlation, creep, and shrinkage) and compared the outcome to alike reinforced concrete made with fresh structural concrete.

The outcome of his work is a unique mix-proportioning technique for concrete made with coarse recycled concrete aggregate, in which RCA is treated as a two-phase material comprising mortar and natural aggregate. The residual mortar in RCA is considered part of the overall mortar (fresh plus remaining mortar) in the mix. "By testing an widespread number of specimens, we have demonstrated that the projected practice would result in creating high-quality, structural-grade concrete, with predictable outcome," said Razaqpur.

Razaqpur hopes this new method to mix proportioning will promote using RCA in structural concrete.

At the same event, Bill Palmer, senior engineer at Total Construction Consultants, a Boulder, Col.-based consulting firm, presented a number of supplementary resources for information on using recycled aggregates in concrete. He listed numerous organizations that can give help and technological information:

The first occasion I'd seen one, was outside a restaurant where I lived and they did a pretty high-quality job, using the portions of an old sidewalk, resourcefully. I never observed something like this before and like the majority of us know, there's a first time for everything. Building concrete stairs with recycled materials got me thinking about other things that we might build with recycled building products.

People aren't just using recycled concrete for stairways, they're using them for undersized retaining walls. Recycled concrete retaining walls and stairways can be built from small to sizeable sections of ruined sidewalks and driveways.
Simply place the broken pieces into attractive patterns, until you have something that functions as a flight of stairs. Start from the bottom and work your way up, until you've fashioned a beautiful recycled concrete stairway.

If you are planning on building a retaining wall out of second-hand concrete, merely stack these materials on top of each other, until you have produced the retaining wall, you envisioned. I don't suggest building retaining walls higher than 24 inches with these kinds of materials.

Article Source: http://www.gamblingarticlessite.net

Recycled Concrete Reinforced Concrete

Please Rate this Article

5 out of 54 out of 53 out of 52 out of 51 out of 5 

Not yet Rated