What Hazards Lie Hidden in a Concrete Slab?

January 31, 2022
It’s amazing what you can find buried within a concrete slab. From cell phones to washing machines and even human remains, there have been quite a few bizarre discoveries over the years.

As far as we know, Jimmy Hoffa has yet to be found!

But forget the outlandish finds for a moment - let’s talk about the more common potential hazards that you might come across on your next project that calls for concrete coring.

Core drilling hole showing conduit

Electrical Conduits

Electrical conduits are rigid tubes that encase lines such as internet cables and electrical service wires. Usually measuring between 20 - 50mm in diameter, they are commonly found within a concrete structure. Hitting one of these can cause power outages, knock out internet connectivity, or damage other essential services in the area. It can also pose a considerable safety risk to the coring technicians on hand. 

Rebar & Wire Mesh

When coring concrete it is important to consider the extent of your work and what the possible implications can be. Reinforced steel, commonly known as rebar, is one of the most hazardous objects to hit. Damaging rebar can cause significant structural damage to a building. It’s also not a quick fix - repairs can be costly and time consuming, resulting in a delayed construction project and additional expenditures. If serious damage is caused, the expertise of a structural engineer may be required. Fortunately, rebar and wire mesh can be identified very easily by concrete scanning using ground penetrating radar.

Rebar and electrical conduit within in a concrete slab

Post Tension Cables

Similarly laid out like rebar, post-tension cables run through slabs to reinforce and strengthen the concrete. Once the concrete is poured and set, the cables are pulled and tightened to further stabilise the slab. A good deal of engineering is required during the process. Cutting into and rupturing cables can cause catastrophic structural damage and result in severe injuries to coring technicians. In some extreme cases, cables have erupted out of concrete and killed nearby workers.

Voids and Air Pockets

Sometimes voids, cracks, and air pockets can form in a concrete slab. This can be caused by a number of factors such as substandard concrete construction, subgrade inconsistencies, extremely cold temperatures, or leaking utility lines. They are often found in roads and sidewalks, walls and floors, pavements, and bridges. Undetected voids can result in erosion or structural collapse, causing unsafe conditions. Cutting into a void can also be very problematic, as this will only weaken the structure further. Fortunately, scanning the concrete prior to cutting can detect a void and determine the extent of damage. This gives engineers and contractors the necessary information to repair the concrete or make alternate plans. 

As outlined in this article, there are many potential hazards that can lie in the depths of a concrete slab. To avoid any unpleasant surprises, it is always important to scan before you cut. Utilizing concrete scanning and imaging methods such as Xradar™ concrete scanning can save time, help make informed decisions, and prevent costly mistakes. With an accurate map of the concrete structure, contractors are able to plan with certainty and coring technicians can cut with confidence. 

If you are in need of concrete scanning or coring services, please give us a call at (604) 305-2818 or send us an enquiry through our contact page.