Strict regulations are placed on the integrity of Concrete and aggregate used in construction projects. Often testing of concrete and aggregate by an independent third-party is necessary to help ensure compliance.
GPR Scanning Perth uses an independent third-party with highly specialist personnel, technology and labs to test our core samples.
We provided a concrete quality inspection service for those who need to know exactly what is going on inside the concrete structure.
The most common items we are asked to check for and identify the level of severity of are the following:
Delamination (concrete and concrete interface)
We are commonly asked to identify if there is any delamination in the concrete between the concrete and concrete interface. This is a very important testing procedure and it is remarkable how accurate the radar scanning is and what it can deliver.
Delamination between the concrete and concrete interface is most commonly caused by a delay in the pour. If the concrete is allowed to set for a few hours before the completion of the pour due to an unexpected delay, a common problem is that the interface or section where the already set concrete and the new concrete are placed together do not bond well together. This causes delamination.
If this is not noted at the time it can be very hard to identify at a later stage from just looking at the surface with the naked eye. You may see a little unevenness on the surface but it is quite hard to see. If you can imagine pouring fresh concrete onto in situ slab without any bonding resin or starter bars then the concrete is very unlikely to bond well and is likely to come away. This is what we mean by delamination. Other causes of it are the mixture of concrete.
When the concrete has not had sufficient time to bleed before it is screeded off then as the water inside evaporates later it leaves the concrete with a porous effect. This can be found on the radar scanners we use. Another way you can determine this is by taking a small core sample and crush testing it at our NATA accredited lab to find out the level of porosity of the concrete and the point it breaks with enough pressure applied. This can be determined by a direct tensile test or a simple crush test.
Bonding between the concrete and bars interface.
When the re bars are moved as the concrete sets this can cause the bars and concrete to either de-bond or not bond at all. This can be due to operators walking on the steel mesh as the concrete is being poured as they operate the vibrators, or in the example of a wall that is poured in sections as it goes up; when the lower part has been poured the re bars stick out the top and can move in the air, this causes the concrete around the bars to be manipulated back and forth and as the concrete sets it can create a void around the bar. This is called deboning. This can be identified by radar concrete scanning with the right equipment and the right software. It requires significant knowledge and experience to identify the concrete properties. By using GPR Scanning Perth, you can be assured that you will be using skilled operators with experience in this field.
The plasticity of the concrete is important as if it does not have enough plasticity than the concrete does not flow well and can congregate around the bars, between the bars and the form work. When there are penetrations in a wall that is been formed up, than there is usually more re bars in the concrete wall below. This makes it harder for the concrete to flow around the bars and reach the surface of the wall where it meets the form boards.
If the bars have not been cleaned well before the concrete is poured this can cause a problem with the bonding. This can be identified by radar concrete scanning.
Cracks, voids, segregation due to over vibration, de bonding between bars and concrete and distribution of constituents are all particulars that can be identified using radar concrete scanning.
Call our Perth office and see if we can help you on your project.
- 3D and 2D scanning of concrete
- Concrete testing to help detect weaknesses like delamination, tanking and honeycombing
- Location of cables in concrete
- Location of utilities like electrical conduits, plastic and copper pipes
- Location of structural elements like PT cables, rebar and reo mesh (reinforcing mesh and reinforcing bars) in suspended slabs
- Non-destructive digging using vacuum extraction