Crushed concrete is a cost-effective alternative to new aggregates. Is this suitable for driveway construction, or should you stick to the tried and trusted materials?
What is Crushed Concrete?
Crushed or recycled concrete aggregate (RCA) is typically sourced from demolition sites. This material, which contains a varying combination of debris, broken concrete, and crushed asphalt, is crushed down to a suitable size and reused as aggregate in new construction. This is an environmentally friendly alternative to placing concrete waste from demolition sites in the landfill.
Since RCA typically contains numerous impurities and is sourced from failed concrete destined for demolition, it’s unsuitable for high-load-bearing applications. So, while crushed concrete isn’t recommended for driveways carrying heavy traffic, it is still suitable for driveways carrying light traffic under specific conditions.
Pros of Using Crushed Concrete as a Driveway Material
Crushed concrete is typically destined for landfills, a costly exercise for demolition companies. They prefer selling this waste product to cover their costs rather than incurring the high costs of taking it to landfill.
Using crushed concrete is also far less expensive for construction companies than sourcing new aggregate from suppliers, decreasing construction costs considerably.
Repurposing waste concrete from demolition sites for new builds decreases the new construction’s carbon footprint and offers old concrete a new lease on life instead of ending in a landfill. Following this route increases the sustainability of construction practices.
- Ease of maintenance:
When installed correctly, crushed concrete requires very little maintenance. This ease of maintenance further decreases the costs.
Crushed Concrete Problems
Since recycled concrete is sourced from various sites, the consistency and appearance vary. This means that the aesthetics of a driveway constructed from crushed aggregate is often inconsistent, which may not be pleasing to the user. This makes crushed concrete driveways unsuited to aesthetic finishes.
- Possible contaminants:
Crushed concrete or RCA is typically sourced from demolition sites, including parking lots, roads, structural elements, and any other structure that reaches the end of its life. Usually, this concrete would have been exposed to various potential contaminants, including exhaust gases, industrial and household chemicals, organic matter, reinforcement metal, and other elements.
These contaminants could negatively affect the durability of the new concrete mix design the RCA is used in.
- Difficulty in finding a suitable supplier:
RCA must be carefully sourced to ensure that potential contaminants are minimized and that the concrete fragments are still sound. In some cases, the concrete’s integrity is compromised because it crumbles when pressure is applied during mixing or when exposed to vehicle traffic. Finding a supplier that ensures high-quality RCA with every delivery is often challenging.
Crushed concrete’s integrity is already compromised to some extent, making it less durable than fresh, well-designed concrete. For this reason, projects using RCA will be less durable than the alternative that uses new only new components.
Driveways made from recycled concrete aggregate are more likely to develop dents, potholes, and ruts early in their lifespan than those constructed of new, hard-wearing materials.
Recycled concrete is typically more permeable than other crushed aggregates used in driveways. For this reason, crushed concrete driveways are far more likely to suffer from moisture damage, such as rutting, than the alternative. This increased vulnerability is especially evident in humid areas.
However, crushed concrete’s permeability can be harnessed and made to play in your favor when applied correctly. When utilized effectively, RCA is perfect for stormwater drainage applications.
Factors to Weigh When Considering Crushed Concrete as a Driveway Material
Due to its vulnerability to moisture damage, crushed aggregate driveways aren’t suitable for areas with humid climates or high rainfall. They will perform far better in dry climates.
2. Traffic volume
Suppose the driveway will likely carry a large traffic volume or heavy vehicles. In that case, crushed concrete is not a suitable construction material. Since it is less durable than alternative materials, it will not perform well under strenuous conditions.
On the other hand, where the vehicles are light, traffic volume is low, or the driveway will likely carry mainly pedestrian traffic, RCA could be an excellent choice for the application.
3. Personal preference
Recycled concrete aggregate has an industrial look and feel, which does not fit within everyone’s personal taste. Consider what the finished product will look like and whether this will fall within your taste before choosing crushed concrete for your driveway.
Crushed concrete is a cost-effective, environmentally friendly option for driveway construction that requires very little maintenance.
However, this material isn’t always aesthetically consistent and often contains high levels of contaminants that could negatively affect its performance. Crushed concrete is also less durable and more permeable than new aggregates, making it unsuitable for high-load-bearing applications.
Before choosing recycled concrete as a construction material, weigh the pros and cons in light of the specific situation. Use this to determine the product best suited to the solution.