United Scanning Services Pty Ltd

United Scanning Services

Structural Assessment of Concrete - Perth

Phone: 08 9294 1832 | Mobile: 0433 724 921


Level 8, 251 Adelaide Tce, Perth WA

United Scanning

Experienced Structural Assessors of Concrete servicing Perth and surrounds

Relative Humidity Testing

United Scanning provides its clients with advice throughout a broad variety of concrete projects. While United Scanning specialises in the use of Ground Penetrating Radar and Electro-Magnetic Detection and Tracing to identify services, reinforcement, defects and other features in concrete, our expertise is much broader than this alone. United Scanning is able to provide information and testing in a range of areas to assist our clients towards successful completion of their planned works.

One area of testing and analysis which United Scanning assists a number of clients with is Relative Humidity (RH) Testing, otherwise known as Concrete Moisture Measurement. The moisture content of concrete is of vital importance in construction projects at three specific points and the required relative humidity within the concrete at these points differs significantly.

The relatively humidity of the concrete while it is being mixed, delivered and poured is critical to the final appearance, durability and defect level of the concrete. Too much water in the concrete can lead to excessive shrinkage, cracking and a reduced compressive strength of the final product. Too little water and the concrete may not mix well, certainly will not flow well and the dryness of the concrete may result in areas of voiding and honeycombing. Typically, a slump test is used to verify the consistency of the concrete allowing our client to assess whether the batch being delivered is fit for purpose, with the adage “When in doubt, throw it out” being an essential piece of construction wisdom.
Concrete Shrinkage Crack

Figure 1: Cracking due to excess shrinkage

While the concrete cures, adequate water is essential and it is a fundamental requirement of the concrete chemistry that the concrete be adequately hydrated. Strong concrete requires moisture with each type of concrete having a specific level of moisture that is required during this stage. Not only must the concrete be adequately hydrated during curing, with the concrete sometimes requiring additional water during this stage (moist curing) but the concrete must also be protected from moisture loss until the curing is complete.

Finally, many floor adhesion products are very sensitive to humidity. Too much water will lead to a failure of the surface to adequately bond to the concrete, while concrete that continues to release water vapour after the surface is applied tend to exhibit bubbling of the surfacing. Drying of the concrete prior to flooring is very important to the longevity and appearance of the surfacing or flooring. Concrete that is drying under normal conditions can take anywhere up to 9 months to reach the appropriate level of relative humidity for the floor surface to strongly adhere or bond.

In summary, during mixing and pouring, the moisture ratio of the concrete needs to be just right, during the curing phase of concrete, relative humidity needs to be kept high, and finally, to allow for effective floor and surface adhering and bonding, the humidity must be relatively low, usually below 75%.
Concrete Drying - interior Slab

Figure 2 : Drying rate of concrete inside a building (indicative)

At each of these stages, accurate knowledge concerning the moisture content and relative humidity of the concrete can assist in the successful and timely completion of project objectives. Knowing early that the concrete being delivered is too dry or too wet can save millions in remediating defects. Monitoring the moisture levels during the curing process can allow for the introduction of additional moisture if it is discovered fluid has leaked or the temperature has resulted in more water than expected evaporating. This will ensure the concrete meets its requirements in terms of compressive strength. Finally, monitoring the relative humidity during the drying of the concrete can allow the application of floor surfaces as soon as the floor is appropriate dry but no earlier and so prevent failure of the surfacing.

Concrete Slump test

Figure 3 : A slump tests success or failure rests partially on moisture content

The absorption, evaporation and migration of moisture through concrete can vary significantly depending on a wide variety of local conditions. The air humidity, the local temperature and air movement level or wind speed can significantly affect the moisture content of the concrete. Even the way the concrete has been worked can change the amount of moisture. A slab that has been power trowelled may have an increased drying time, while other treatments of the surface may speed up evaporation and drying.

RH testing is an essential part of successfully completing a concrete project. While it is possible to estimate the amount of moisture at each stage in the process, using calculations to assess water ratio in the concrete mix, required moisture for hydration during curing and maximum humidity for bonding of surfacing adhesives, these are still only estimates and no substitute for testing. Ambient conditions may cause the actual value to differ wildly from what is estimated at any stage and deliver results that are less than optimum.

Being able to provide clients with clear insights into the humidity of their concrete and do so in a timely and accurate way, is an incredibly useful tool for our client and is a service that United Scanning is an experienced provider of.

Accreditations and Approvals

  • Telstra Communications
  • ATCO Gas
  • White Card
  • Working at Heights
  • WA Gas - WestNet Energy
  • Western Power
  • Water Corporation
  • Current Driver’s License
  • Senior First Aid
  • Confined Spaces
  • PTA Rail Access
  • Ground Penetrating Radar Theory and Application

Our Services

  • Concrete Scanning using GPR
  • Service Location
  • Structural Assessment of Concrete
  • Reporting


"Thanks again for your quick response to this enquiry! Your technician was superb too - very friendly and professional."

Chief Strategy Officer | Sadleirs Perth

"Lee was really helpful on site with the Dampier job, could not have asked him to do a better job... we were really impressed with the work he did up there."

Hannah Wood | HSE Consultant | Prensa Pty Ltd

"... appreciate the quick turnaround and your time and guidance on site."

RAAF Learmouth

"I was pretty happy with the way Jamin and Gary worked; please pass on my thanks."

Envar Group

"Main Roads WA engaged United Scanning to undertake service locating works as part of the Northam Pithara Rd realignment project. Although the scope of works altered a few times due to external circumstances, United Scanning personnel completed all required objectives. United Scanning was also prompt and efficient through correspondences with MRWA personnel."

Main Roads WA

"Just a quick note to say thank you for an excellent service! Matthew did a great job and found the cables we were looking for. He was very helpful and did everything he could to assist."

Brightwater Care Group

"Broad thanks United Scanning Services for the efforts and involvement in the delivery of this challenging project and given the opportunity would happily engage again with United Scanning Services in the future."

Perth Domestic Airport

"It's a great outcome that Jamin was able to detect the cable and he was early, polite and capable."

"We were really happy with the service from Jamin in the field."

Aurora Environmental

Morning Matthew, a brief note to the team, all went well this morning which is great. Great service end to end when we required professional services urgently.

Own Valli - Middleton Homes

Examples of our reports

Non-Destructive Testing Report

Non-Destructive Testing Report

Download Sample

(PDF 1.3MB)

NDT Report on concrete walls

NDT Report on Concrete Walls

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(PDF 3.45MB)

Structural Assessment Report

Structural Assessment Report

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(PDF 882KB)

Site Location Scanning Report

Detailed concrete scanning report

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(PDF 8.3MB)

GPR Concrete Scanning Capabilities

GPR Concrete Scanning Capabilities

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(PDF 1.6MB)

Concrete Scanning Report

Concrete Scanning Report

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(PDF 7 MB)

United Scanning - Specialists in Structural Assessment of Concrete, Perth, Western Australia

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