Can Concrete Be Recycled?

Ever wonder what happens to all of that concrete after a large demolition or construction project? While it was once commonplace to find this discarded concrete in landfills across the globe, today more and more companies are acknowledging the environmental benefits of recycling concrete. Each year, over 265 gallons of cement is manufactured for each person on the planet. To put that into context, the United States produces over 325 million tons of concrete demolition waste each year and recycles close to 140 million tons of concrete, thus, not only can concrete be recycled, it is highly recommended.

Recycled concrete remains cost effective and environmentally conscious. The environmental benefits of recycling concrete include:

• Keeps concrete, which is not biodegradable, out of landfills
• Saves water by reusing premixed concrete instead of mixing new material
• Reduces the need for gravel mining

Concrete Recycling Process

Surprisingly simple, the concrete recycling process involves breaking down concrete into large pieces, small pieces, or fine particles to be reused for other construction needs. The process of recycling concrete is actually quite simple:

Step 1:  Concrete is collected at the worksite and broken down into smaller pieces using a crushing machine.

Step 2: Non-concrete materials, such as rebar, are sorted from the debris using magnets and other methods.

Step 3: All aggregate pieces are sorted by size.

Larger pieces can be used for erosion control or put through the crushing machine again for further refinement. Smaller pieces can be used as gravel or a base layer for asphalt.

The Conco Companies are one of the foremost suppliers of concrete services for the Western U.S. We got our start in 1959 in the Bay Area by offering clients the best value on a broad range of concrete services and products.  Since that time, we have taken a leading role as top concrete contractors in the region. We have four regional offices serving California, Oregon, Nevada, Colorado and Washington.

Source:  http://www.wbcsdcement.org/pdf/CSI-RecyclingConcrete-FullReport.pdf

Blended Cements

The American Concrete Institute’s (ACI) Cement and Concrete Terminology, defines blended cement as “hydraulic cement that is produced by intergrinding portland cement clinker with the other materials or by blending portland cement with the other materials or a combination of intergrinding and blending.”  As recently as 2012, there were changes made in blended cements that have been approved by the ASTM for both special applications and general use.   

 

From the ASTM’s C595 abstract on hydraulic blended cements, they describe Type IS as Portland Blast-furnace Slag cement and Type IP as Portland-pozzolan cement.  They state that, “They can also be described according to air-entraining, moderate sulfate resistance, moderate heat of hydration, high sulfate resistance, or low heat of hydration properties.”  Type I (SM) Slag-modified Portland cement has a standard that contains less than 25% slag by mass of the cement.  The ASTM’s C595 permits Type IS Portland Blast-furnace Slag cement to contain between 25 and 70% by mass of the finished cement. 

Blended cements are used to prolong the life span of concrete as it reduces the concrete’s permeability to water.  Whereas concrete mixes made of portland cement are more porous and are susceptible to cracking during freeze/thaw cycles.  It can even be a cause of deterioration in the rebar as moisture can seep in over time.  Another benefit to blended cements is they reduce the water-cement ratio (w/c), which is one way to produce high-strength concrete. 

Blends can be customized by varying the proportions of the mix and be produced to meet the demands of a specific project.   Most importantly the ASTM dictates that, “cement shall undergo different tests to determine the following properties: chemical analysis, fineness by sieving, fineness by air-permeability, autoclave expansion, time of setting, air content of mortar, compressive strength, heat of hydration, normal consistency, specific gravity, water requirement, mortar expansions of blended cement and pozzolan, drying shrinkage, activity index with Portland cement, and sulfate resistance.”

* ACI 116R-00, Cement and Concrete Terminology, American Concrete Institute, Farmington Hills, Michigan, 2000

* http://precast.org/2012/12/new-astm-blended-cement-types/

* http://www.astm.org/Standards/C595.htm

 

When your project demands exceptional services and the best value, Conco can deliver.  We have been offering premium concrete services throughout the Western U.S. since 1959, and have a regional office in the Seattle area.  With state-of-the-art equipment and modern facilities, we work diligently to meet goals and stay within budget.

The Beautiful Ashton in Downtown Bellevue, WA

This mixed-use, luxurious apartment building, located in downtown Bellevue, WA was constructed to include all the amenities and finishes generally only found in high-end condominium properties.  Conco was a part of the skilled team that constructed the beautiful, 20-story Ashton Bellevue Towers. 

The sleek, contemporary Ashton was designed with an urban concept and has 202 sizable apartments with 14 townhouse/lofts.  The offerings include 115 one-bedroom homes that come with or without a study, 61 two-bedroom units, and 12 penthouses.  The units provide residents with spectacular views of the Cascade and Olympic Mountains, Lake Washington, and downtown Seattle.  

This was another project from the award-winning contractor, The Hanover Company, who built the Ten20 Tower located just across the street.  CollinsWoerman, a leading expert in sustainable architecture and infrastructure, was the architect on the project and was also a part of the Ten20 Tower.  The engineer was the S.C.A. Consulting Engineers.   Once again Conco delivered premium concrete services for the 20-story structure. 

One of the biggest differences the Ashton offers from other apartments is a very large 9,000 sq. ft. amenity space that has a fitness center complete with a spinning room, aqua lounge, conference room, and a movie screening room.  The building has a 5-level, private parking structure that can accommodate 354 cars.  The ground floor is 2,650 sq. ft. of commercial retail space.     

In addition, the Ashton Bellevue offers residents 24-hour concierge services and an elevated outdoor great room equipped with grills and a dual-sided fireplace.  The building’s location allows residents to conveniently walk to restaurants and boutiques as well as access to Bellevue’s cultural district.    

For over 50 years, Conco has been providing premium concrete services and is one of the most trusted concrete contractors in Seattle.  We partner with clients on every project from the pre-construction stage right through to final completion to maximize efficiency and ensure goals and budgets are met.  Our concrete services include commercial, educational, parking and other construction development as well as public works projects.

Elkhorn Court Apartment Homes

Conco had the opportunity to provide concrete services for a development of multi-family homes designed to offer novel solutions to meet demand for housing in the Bay Area.  The Essex-Elkhorn Court Apartment Homes in San Mateo, California, a mixed-use project, is one of the many developments of its kind being built throughout the country.  The well-planned neighborhood offers many amenities to its residents and the surrounding community.

 

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