Why To Use Recycled Concrete In Your Next Project
by TRP Ready Mix on September 13, 2022
Tips For Using Recycled Concrete
The construction industry is vital, but it also has a problem. According to the Canada Green Building Council, building materials and construction are responsible for around 13% of the country’s carbon emissions. Considering existing buildings contribute 17% each year, this shows that there is work to be done.
Using more sustainable materials is a key way that construction businesses can reduce their carbon footprints. If you run a construction business, you should consider recycled concrete. But what is concrete recycling, and what is recycled concrete used for?
We’ve created a recycled concrete guide to explain everything you need to know about how to use recycled concrete.
What Is Recycled Concrete?
Construction projects – especially those that start with demolition – produce a lot of waste concrete. Old, broken concrete seems pretty useless. It’s not biodegradable, and it’ll often end up in landfill.
Recycled concrete works by breaking down old concrete and using it as aggregate for new concrete. It can also find a new life as a filler for gabions or for building retaining walls around bodies of water (commonly called riprap revetments).
Another use is simply instead of traditional aggregate materials. It can form a sub-base for a wide range of projects, including road construction and parking lots. It can also be used for trench backfilling and light fixture bases.
How Is Recycled Concrete Aggregate Produced?
To turn old concrete into recycled aggregate you need to feed it into a powerful crusher. This breaks down large pieces of concrete waste into smaller pieces. Depending on the type of concrete waste you’re dealing with, it may need to be screened.
The main contaminants to remove are:
- Steel reinforcement
- Other metals
- Other debris
If you regularly work on large-scale construction projects, it may be a wise move to invest in crushing and processing equipment that you can use on-site. Alternatively, you can purchase concrete containing recycled aggregate from a ready-mix company.
Equipment Needed To Recycle Concrete
There are a few different types of crushers that can be used to recycle concrete. The most common is the jaw crusher.
Jaw crushers open and close like a mouth. They subject the larger pieces of concrete to huge pressure from above and below which pulverises it. They’re great for breaking down big pieces of concrete but have their limitations.
They are not capable of crushing the concrete into fine aggregate. Your options for using recycled concrete made in a jaw crusher are more limited due to the large size of the pieces.
This is the least popular type of crusher for recycled concrete. It funnels the concrete pieces into a cone where they get crushed. It’s not able to tolerate contaminations in the material, which limits its usefulness.
Impact crushers have a crushing chamber. The machine then acts like huge hammers. The pieces crash into the wall of the chamber which crushes them further.
The impact crusher allows you to enjoy the most recycled concrete benefits. It can produce aggregate as small as 3/4″, making it useful for many more applications.
One of our best recycled concrete tips is to invest in an impact crusher if you’re serious about large scale use of recycled concrete on your projects.
Where To Use Recycled Concrete?
Interestingly, across the border in the United States it has been common practice to recycle concrete for use in road building since the 1940s. In Europe, concrete salvaged from demolition projects is seen as a valuable resource. In Canada, it has been common to send this to landfill, but now times and practices are changing.
Some of the potential uses of recycled concrete include:
- Sub-base of buildings – even suitable for use on soft ground
- Backfilling trenches
- Sub-base for walkways and paths
- Retaining walls
- Gravel alternative for drainage
When combined with virgin materials, it can also form the aggregate in new concrete. In this form, it can be used in any regular concrete application.
The Pros Of Using Recycled Concrete Aggregate
The main recycled concrete advantages are cost and environmental impact.
At the most basic level, there is always a cost saving when you transition from buying a product to using what you already have. Of course, there are additional costs to consider. The crushing equipment is costly and requires ongoing repair and maintenance.
There are also energy costs to consider when you make your own recycled concrete aggregate. But there are also costs involved with sending concrete waste to landfill. It’s well worth crunching the numbers for your operation to see how much you could save.
Research published by Queen’s University in Kingston, Ontario noted that reinforced concrete infrastructure accounts for 10% of global CO2 emissions each year. A handy comparison is the aviation industry, which produces around 2%. Anything that we can do to reduce the amount of concrete that needs to be produced will help.
Keeping concrete out of landfill and recycling either as aggregate for sub-bases or to mix with virgin materials makes sound environmental sense.
The Cons Of Using Recycled Concrete Aggregate
Concrete made with recycled aggregate has had a reputation in the past of having lower strength and elasticity in comparison with concrete made from virgin materials. But recent tests have shown that certain types of recycled concrete can form as well or even better than regular concrete.
Recycled concrete aggregate has higher water absorption than natural aggregate. However, it absorbed less when the particle size was lower. Refining the particles further makes them more usable, but results in higher costs.
This means that is may not be suitable for all structural projects. If you’re considering using recycled concrete in your project, get it tested first. Consult a structural engineer to see if they’re confident that it is up to the job.
Why You Should Use Recycled Concrete
Recycled concrete is a versatile material that is suitable for a huge range of projects. It can save you money and reduce the environmental impact of your projects.
For more information about how our concrete services can benefit your business, contact us today!