GPR Services
Pavement Thickness and Road Void Detection Survey
A cavity beneath a road forms long before anything appears at the surface — and by the time it does, the question is no longer investigation but closure.
What a collapse actually is
Water escapes.It carries fines away.The cavity grows for months.Then the surface gives.Road collapses are almost never sudden. They are the visible end of a process that started with a leaking drain and continued out of sight while the surface still looked sound. Radar finds that process while it is still cheap to fix.
Continuous layer profiling · Grid density stated in every report · Cause identified, not just symptom
Quick AnswerMezux Touch carries out pavement thickness survey and road void detection by GPR — continuous profiling of bound course thickness and sub-base condition, and cavity detection at a grid density set for the smallest void that would matter to the client rather than for utility spacing.
Why coring cannot tell you what radar can
A core gives one exact number at one point and nothing between. On a road where thickness varies, coring on a blind grid means either an expensive number of holes or a picture built on assumption between them.
Radar profiles continuously along the run, so a thin section between two adequate cores is found rather than averaged away. That is the difference between knowing a road and sampling it.
Why road voids differ from voids elsewhere
A cavity beneath a building slab sits in still ground. A cavity beneath a road sits under repeated dynamic loading, which means it grows faster and fails more suddenly than the same void would in a quieter setting.
It also means the surface gives no warning proportional to the risk. A road can look sound over a cavity large enough to take a vehicle, because the bound pavement courses bridge it until they no longer can.
That combination is why we treat road void work as its own service rather than as void detection carried out on a road, and why the grid density we recommend here is tighter than we would use on a building slab.
How this survey is run
What is actually being asked?
Thickness assessment, sub-base condition and void detection are three different surveys at three different grid densities. Scoping which is needed avoids paying for the wrong one.
Density set by the smallest thing that matters
For voids, the grid is set against the smallest cavity that would concern the client rather than a standard spacing. That figure is agreed before work and stated in the report.
Continuous rather than sampled
Layer interfaces and sub-base condition are recorded along the whole run, so a thin or weakened section between sample points is found rather than assumed away.
Passes run in two directions
A void's response varies with the angle of approach, so single-direction coverage misses cavities that a perpendicular pass would show clearly.
Mapping outward from a find
When a void is detected we scan outward to establish how far support has been lost, because extent is the client's real question rather than the centre point.
Looking for what created it
Most road voids are made by water. Where a drain runs through or beside the anomaly, that is reported so the remedy addresses the cause rather than only the hole.
Confidence stated per finding
Anomalies are graded by how consistently they returned across passes. Where a response is ambiguous between a void and a soft zone, we say so rather than committing.
Recommending confirmation where warranted
Ambiguous findings carry a recommendation for probe or intrusive confirmation, with the position chosen to resolve the question rather than to confirm what is already clear.
What clients most often already know
That the road keeps failing at the same spot. What they usually do not know is why, because the repair has addressed the surface each time and the cause sat below it.
A profiled run frequently shows a drain running through the failure zone with a cavity around it, which turns a recurring maintenance cost into a one-off repair.
Where road failures bring us out
Road cavity work and pavement assessment are commissioned together because the same pass produces both. Pavement GPR work and road void detection share equipment and grid, which is why they are usually commissioned together on a failing stretch. Repeat failures and suspected cavities across NCR are attended from Faridabad, usually the same day. Achievable depth differs by area, which affects how small a void can be found:
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Frequently asked questions
That depends entirely on line spacing, which is why we state it. A cavity smaller than the grid is stepped over, so the grid is set against what would matter to you.
Often, from the sharpness of the response, but not always. Where it is ambiguous we say so and recommend a probe.
A core gives one number at one point. Radar profiles continuously, so a thin section between two adequate cores is found rather than averaged away.
Water, in almost every case — a leaking drain washing out fines, or repeated saturation moving material until support is lost.
Extent, because how much ground has lost support is the actual question. We scan outward from a find rather than stopping at its centre.
Same stretch of road failing repeatedly?
Ask for a profile rather than another repair — the cause is usually below the surface that keeps being patched.
Get A Quote +91 99100 10209Road void work — dynamic loading, timing and detailed questions
Cavities beneath roads behave differently from cavities anywhere else, because the ground above them is loaded repeatedly by traffic. That single difference changes how fast a void grows, how little warning the surface gives, and how tight the survey grid needs to be.
Why the surface stays sound until it does not
Bound pavement courses bridge a cavity beneath them, distributing load across the gap in a way a building slab over still ground does not have to. That bridging is what allows a road to look and feel normal over a void large enough to swallow a wheel, and it is why visual inspection and even a walked survey give so little warning. The failure, when it comes, is sudden precisely because the structure was working right up to the point it stopped.
When to commission this survey
After a repeat failure at the same location, because a third repair on the same stretch is a strong indicator that the cause was never addressed. After a known leak on a main beneath a carriageway, since water escaping under a road is the most reliable void-forming mechanism there is. Before resurfacing a length, because laying new bound courses over a cavity buys a few seasons and no more. And routinely on stretches carrying heavy vehicles over old drainage, where both the loading and the mechanism are present together.
Beyond the basics
How fast does a road void grow? Faster than one in still ground, because repeated loading works material into the cavity. A void found this season is not the size it was last season.
Can a walked inspection find one? Rarely. The bound courses bridge the gap, so the surface feels sound until the bridging fails. That is the whole difficulty.
Is resurfacing over a void ever acceptable? It buys time and nothing more. New courses bridge the cavity for a few seasons, after which the failure returns larger.
What grid density do you use on roads? Tighter than on a building slab, because traffic loading makes a smaller cavity consequential sooner. The figure is stated in every report.
Do you find the leak that caused it? We identify a drain or main running through the anomaly where one is present, so the remedy addresses the mechanism rather than the hole.
Terms used on this page
Bridging — the load-spreading action of bound pavement courses over a cavity, which masks it. Dynamic loading — repeated traffic loading, which accelerates cavity growth beneath a road. Repeat failure — the same stretch failing more than once, a strong indicator of an unaddressed cause. Void-forming mechanism — the process creating a cavity, usually water escaping and carrying fines away. Grid density — survey line spacing, tighter on roads than on static structures.
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