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September 9, 2021 admin

Concrete Strength Testing

Infrastruct provides our Clients with a wide range of practical solutions for both Intrusive and Non-Destructive (NDT/NDE) evaluation of concrete strength on many types of structures including motorway and road bridges, single and multi-storey buildings, tunnels, dams, drinking water reservoirs and concrete tanks.

An evaluation of the compressive strength of hardened concrete is frequently required in the construction industry. There are many reasons to assess the compressive strength of concrete including:

A requirement by the designers to verify the compressive strength in an existing structure that will be structurally modified, redesigned for other uses or where the structure was damaged i.e. fire.
A requirement to check the structural adequacy in the case of a non-conformity of the standard cube test (or when cube results are not available to the designers.
In the case of a dispute over concrete quality or defective workmanship in new construction works.

The main Standard providing information on the approaches to be adopted as part of an evaluation is I.S. ‘Assessment of in-situ compressive strength in structures and pre-cast concrete components’.

I.S. EN 13791:2007 provides guidance on direct (cores) and indirect (Rebound Hammer, Ultrasonic Pulse Velocity and Pull-out Force) methods for assessing the in-situ compressive strength of hardened concrete.

At Infrastruct, we provide the following testing to assess compressive strength of hardened concrete:

Diamond coring of the concrete elements and structures – Core diameters: 50mm, 75mm, 100mm, 150mm
Rebound Hammer testing (normal and early age concrete testing)
Ultrasonic Pulse Velocity (UPV) testing
SonReb testing and analysis
Capo and Lok testing

Test results and related information is provided in a detailed report with interpretation and AutoCAD drawings.

Also, as part of our Services, we can work with our Clients to monitor strength development in early age concrete structures using the Maturity method (ASTM C1074). This is a non-destructive testing approach that allows us to estimate the early-age and compressive strength of in-place concrete in real-time. The technique is based on the principle that concrete strength is directly related to its hydration temperature history.

For more information on this or any construction-related testing, please contact us.

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September 9, 2021 admin No Comments

Structural Inspections

Infrastruct is focused on providing a quality based, cost effective inspection, testing and investigation services using our best resources to fully understand the in-situ condition of structures.

Our team is highly experienced in the inspection and investigation of all type of building and civil engineering structures and we have the safety related training including, confined spaces entry, MEWP operations, abrasive wheels, manual handling and Safe Pass to carry out our Client’s requirements.

Structural Inspection of structures include:

Motorway and regional route bridges
Drinking water reservoirs
Liquid retaining concrete tanks
Multi-storey buildings
Single storey buildings
Tunnels
Basements
Industrial buildings
Open framed structures
Marine Jetties and Piers
Heritage structures
Agricultural structures

All our structural inspections are completed by a Chartered Engineer and the inspections and test results are provided in a detailed report with interpretation and AutoCAD drawings

Structural inspections are often supplemented with testing and investigations to determine the cause, extent and severity of noted defects or deterioration on structures. There are many structural testing and investigation techniques currently available to engineers to examine and rapidly assess the cause, extent and severity of structural defects and to determine the overall condition of structures.

The range of testing and investigations available to Infrastruct as part of our Structural Inspections services are as follows:

Concrete Structures – Reinforcement Surveys	Concrete Structures – Quality & Integrity Surveys	Steel Structures – Testing	Material Sampling for Analysis
Covermeter surveys	Ultrasonic Pulse Velocity (UPV) testing	Ultrasonic Thickness (UT) measurements	Chloride content analysis
Ground Penetrating Radar (GPR) surveys	Rebound Hammer testing	Portable Hardness testing	Carbonation depth testing
Half-Cell Potential surveys	s’MASH Impulse Response testing	Magnetic Particle Inspection (MPI)	Cement content analysis
Linear Polarisation Resistance (LPR) measurements	DOCter Impact Echo testing		Sulphate content analysis
Resistivity surveys	CTG2 Concrete Thickness measurement		Alkali content analysis
Delamination (sounding) surveys: Hammer tapping Delam tool surveys	Crack Pattern and Analysis Crack length Crack depth Crack width		Coring (75mm, 100mm & 150mm): Compressive strength Tensile Strength Density
Targeted Breakouts	MIRA Pulse Echo Thermography		Petrographic examination
	Permeability testing (site)		Permeability testing (laboratory)

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February 2, 2021 admin

Infrastruct Structural Testing Services for Construction

There are many structural testing and investigation techniques currently available to Owners, Operators, Engineers and Architects to examine and rapidly assess the condition of their structures. Many of these tests use Non-Destructive Testing or NDT techniques.

When the need for testing arises, either on a construction site or for existing structures, due to unknown structural properties, structural defects or material deterioration, we can use a variety of NDT techniques and intrusive investigations to determine material properties, assess the cause of defects and examine the extent and severity of deterioration. Structural testing and investigations can be used on single elements or can be expanded to assess the overall condition of existing structures.

Testing methods such as cover surveys, half-cell potential surveys and resistivity surveys on embedded reinforcement provide the essential data for a standard condition assessment of reinforcement.

A covermeter survey will quickly determine the depth of cover to reinforcement and with modern covermeters, we can determine reinforcement layout to depths of up to ≈160mm in the concrete. Moreover, covermeters can now generate images of the embedded reinforcement and estimate the rebar diameter for on-site review.

Cover meter surveys are restricted to the top mat of reinforcement in concrete. Hi-frequency Ground Penetration Radar (GPR) systems are now readily available for testing concrete structures and imaging to depths of ≈550mm. GPR for concrete structures is used by Infrastruct to gather information on rebar layouts, locating hidden defects, locating post-tensioning cables and in conjunction with the other test systems below confirming the integrity of concrete structures.

Half-cell potential surveys and resistivity measurements will indicate the risk of reinforcement corrosion in concrete but adopting the Linear Polarisation Resistance (LPR) technique will allow a determination of the rate of reinforcement corrosion.

The need to understand the in-situ compressive strength of concrete is a basic requirement for Engineers and Architects to push forward with their construction projects. Rebound Hammer surveys often referred to as Schmidt Hammer surveys are useful for screening concrete in advance of concrete coring operations. If a calibration curve, specific to a concrete region is prepared, a Schmidt Hammer survey can then be used to estimate the in-situ compressive strength of concrete.

Concrete quality and the integrity of placed concrete will affect the in-situ compressive strength and durability of concrete. Engineers and Architects need to have confidence that the concrete placed on their projects is of good quality and that there are no hidden defects within the concrete.

At Infrastruct, we use different techniques depending on the site conditions and information required. Ultrasonic Pulse Velocity tests, also referred to UPV surveys, are very useful to classify the quality of the in-situ concrete. UPV surveys are completely non-destructive and are useful for many structural configurations.

Ultrasonic Pulse Echo surveys and Impact Echo testing can locate and quantify the extent of hidden defects in hardened concrete. At Infrastruct we use the MIRA pulse echo tomograph and DOCter Impact Echo equipment for location of hidden defects in concrete structures.

Concrete permeability is critical to the durability of concrete in all service environments. Permeability is determined by many different techniques and on-site this can include air permeability testing and water permeation testing. At Infrastruct, we use different techniques, depending on requirements, to carry out concrete permeability surveys including the GWT permeability method from Germann Instruments. Careful surface preparation, understanding the moisture condition of the concrete and measurement of concrete resistivity are important for accurate surveys on existing structures.

Mechanisms that can cause concrete deterioration or corrosion of reinforcement are common and can, under certain conditions, rapidly affect the durability of concrete if we do not know the attack is on-going. Carbonation testing is used to determine the penetration of the carbonation front into concrete over time. The risk of carbonation-induced corrosion increases when the depth of carbonation is equal to or is greater than the depth of rebar cover. The rate of carbonation penetration can be modelled for individual structures for residual service life calculations.

The chloride content of concrete in structures is determined using shallow sampling depth increments, collecting the concrete dust samples and analysing the samples for chloride concentration and plotting a profile of chloride concentration versus depth and comparing the chloride content in the concrete to the depth of reinforcement cover. Chloride testing is essential to determine the risk of chloride induced corrosion of reinforcement in concrete. The rate of chloride ingress is important and can be modelled for individual structures for residual service life calculations.

The above concrete testing systems can provide Engineers and Architects with pertinent information on the condition of their structures. However, it is critical that the information gathered is correct, accurate and taken from specific locations on the structure. We always recommend that structural testing and investigations are carried out by competent engineers and technicians, trained and experienced in the use of structural test equipment.

If you require more information on structural testing and structural investigations, the right test equipment for your project or interpretation of test results or test information then please don’t hesitate to contact us at info@infrastruct.ie.

Covermeter Survey

Cover meter Surveys

Covermeter Scan Result

Half-Cell Potential Survey

Resistivity Surveys

Rebound Hammer Survey

Schmidt Hammer Survey

Ultrasonic Pulse Velocity testing

UPV Survey

Ultrasonic Pulse Echo Survey

Impact Echo Testing

Air permeability of concrete

Water permeability of concrete

Carbonation in Concrete

Chloride Profile in Concrete

GPR for Concrete Structures

Rate of reinforcement corrosion using LPR

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October 23, 2020 admin

Infrastruct Welcomes New Engineering Staff to the Company

In August, Ethan Mannion and Dr Shahnur Alam Sourav joined Infrastruct to work on structural testing and investigation projects in Ireland and the UK.

Ethan is a Mechanical Engineer with experience in both the manufacturing and construction industries.

Shahnur recently completed his PhD in UCD and joins Infrastruct to further enhance our testing and investigation services.

Since joining Infrastruct, Ethan and Shahnur have been involved in structural investigations in multi-storey buildings, moisture monitoring in both new and existing buildings, non-destructive testing to determine floor slab depth and integrity in open tanks and a Special Inspection of a 72 year old concrete bridge.

These projects involved many types of tests including:

Covermeter and GPR scanning of different types of structural elements
Half-Cell Potential and Resistivity mapping on structural elements
Relative humidity mapping in floor slabs
Pulse Echo mapping of a bridge deck to determine the in-situ depth of the deck
Ultrasonic Pulse Velocity (UPV) testing on structural elements (SonReb Analysis)
Rebound Hammer testing on structural elements
Sampling and testing for carbonation depth and chloride ion concentration of concrete
BRE Screed testing on repairs floors
Anchor testing
Defects mapping

All testing and investigation works completed by Infrastruct is supervised by a Chartered Engineer and we prepare a detailed interpretative report with AutoCAD drawings (as required) for our Clients.

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June 15, 2020 admin

Impact Echo Testing on Existing Concrete Floors

Impact Echo is a non-destructive test system for examining and assessing concrete elements in structures. Impact Echo is used for:

Location voids and honeycombing in concrete structures (depth of defects in elements)
Locating delamination (at reinforcement) in concrete structures
Determining voids in post-tensioning ducts
Structural thickness of elements.

Infrastruct uses the Germann Instruments DOCter Impact Echo system.

Impact Echo uses a sharp mechanical impact on the concrete surface to generate stress waves that penetrates through the concrete. The stress waves travels into the concrete and are reflected from the back wall of the element or from an anomaly within the element, for example a void. The reflected stress wavesare picked up using a sensitive displacement transducer placed about 50mm from the impact point.

Impact echo is an expert system requiring a detailed knowledge of its use, the technique and knowledge of the concrete element under test.

Examples of Use:

Locating Voids in Post-Tensioning Ducts

The team in Infrastruct were requested to non-destructively examine post-tensioned downstand concrete beams and determine the location and condition of the ducts.

We used high frequency GPR to locate the duct profile within each concrete beam and we used the DOCter Impact Echo system at small intervals to assess and record the void condition within the ducts. This was very successful at locating voids in post-tensioning ducts.

Selected duct and tendon exposures were made to confirm the findings of the DOCter Impact Echo system.

Figure 1 shows the DOCter Impact Echo system in use on the Bridge and Figure 2 shows a voided post-tensioning duct located using the DOCterImpact Echo system.

Locating Piles under Existing Floor Slab

The team in Infrastruct were asked to determine, non-destructively, the depth of a concrete slab and to locate buried piles under the concrete slab.

We used a combination of test systemsincluding the impact echo which was particularly useful in areas of congested reinforcement. The piles were located and marked up on the concrete surface and a detailed report prepared for the Client.

Figure 3 shows the DOCter Impact Echo system in use on the floor slab to locate changes in the thickness of the floor.

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June 15, 2020 admin

Moisture Testing in Concrete Floor Slabs

Concrete floors and screeds should be dry enough to allow resilient floor coverings to be installed without follow-on moisture-related damage.

If moisture is present in a concrete floor slab or screed it can:

Cause damage to the floor covering material
Affect certain flooring adhesives
Cause bubbling, blistering or delamination of the floor coverings
Affect certain types of levelling compounds or underlay materials
Damage certain screed materials
Affect or damage wall or skirting materials or finishes.

The drying out of a concrete floor slab (moisture leaving the slab over time) is typically a slow process and a common method for assessing the floor condition is using in-situ relative humidity probes.

Infrastruct use the Tramexhygro-i₂probes for in-situ relative humidity monitoring of concrete floor slabs and screeds.

ASTM Standard F2170-19a ‘Standard Test Method for Determining the Relative Humidity in Concrete Floor Slabs Using in-situ Probes’ describes the quantitative determination of the percent relative humidity in concrete slabs.

A summary of the procedure to measure relative humidity in concrete floor slabs is as follows:

In hardened concrete floors or screeds, drill a hole with a specific diameter in the floor to a predetermined depth and clean out using a hole brush and vacuum system. Avoid embedded reinforcement, if present, in the slab. See Figure 1 showing rotary drilling in a concrete slab with a dust removal system prior to inserting the plastic sleeve.
Push a plastic sleeve, of suitable length, into the drilled hole and cap off and seal. The plastic sleeve allows measurement of the relative humidity of the concrete at a specific depth.
Install the relative humidity probe into the hole and recap as shown in Figure 2.
The Standard F2170-19a recommends a defined number of RH% probes per square meter in the floor slab and requires certain test locations to gather as much information on the moisture distribution in the floor.
Allow at least 24 hours for the RH% probes to achieve moisture equilibrium within the sleeve before making the relative humidity measurement. We measure relative humidity in concrete and screeds using the Tramex CMExpertII system as shown in Figure 3.
Record the result carefully ensuring the reading does not drift by >1% and the probe is in temperature equilibrium with the floor.

Non-Destructive Moisture Measurement

To scan concrete floors for changes in the moisture content, the Infrastruct Team also uses the Tramex CMExpertIIdigital meter (Impedance Mode). In this mode, the meter measures the surface moisture using the electrical impedance principle.

Measurements are non-destructive and large areas can be scanned quickly. See Figure 4 showing the Tramex CMExpertIIdigital meter in operation on a floor slab.

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April 8, 2020 admin

Permeability Testing On Underground Concrete Tanks

In early 2020, Infrastruct was requested to carry out in-situ permeability testing on underground reinforced concrete tanks for a large and well-known Irish manufacturing Company. The testing on the concrete tanks was required to assess, non-destructively, the in-situ quality of the concrete and its resistance to water penetration prior to entering service for the Company.

The permeability of concrete to liquids has major implications for the durability of the concrete during its service life and on its ability to retain the liquid within the tank structure. While there is no one standard test method recommended, Infrastruct uses the Germann Instruments GWT test system for the on-site assessment of water permeability.

The GWT system can be used for:

1. Evaluation of the water permeation of the skin-concrete in finished concrete structures.
2. Testing the water tightness of construction joints and sealed control joints.
3. Testing the concrete surface before and after the application of a protective water-proof coating to assess the effectiveness of the coating and its application.
4. Evaluation of the water permeation properties of masonry structures.

Photographs 1 and 2 below show the GWT test system on the reinforced concrete walls of the underground reinforced concrete tank. Note the marked-up location of the embedded reinforcement within the walls, it is recommended to avoid testing over the reinforcement.

The results of the GWT testing was recorded on-site by our Engineers and a comprehensive report, with interpretation, was prepared for our Client.

For more information on GWT testing or any structural testing and investigations, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

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March 5, 2020 admin

BRE Screed Testing On Floors

Infrastruct was requested by a materials manufacturer in January 2020 to carry out in-situ testing on a floating screed floor.

The methodology to assess the In-situ Crushing Resistance (ISCR) of bonded, unbonded and floating screeds is provided in BS 8204-1:2003 ‘Screeds, Bases and In Situ Floorings – Part 1: Concrete Bases and Cementitious Levelling Screeds to receive Floorings’.

Infrastruct used the BRE Screed Tester for the in-situ testing on this screed. The equipment used a 2kg weight (floating screed, Category C only) dropped 1m down a vertical rod onto a foot piece to impact the screed surface over a 500mm2 area. The surface indentation caused by the four consecutive blows onto the screed in the same area was measured and recorded using a simple portable dial gauge device.

This test is very useful for identifying zones of poor compaction beneath an apparently good surface.

Photographs 1 and 2 below show the BRE Screed Tester using the 2kg weight on the Category C floating screed and the portable dial gauge device, zeroed on the test area before the testing and replaced on the test area after the testing to measure the indentation depth.

The results of the testing was recorded on-site by our Engineer and a comprehensive report, with interpretation of the results, was prepared for our Client.

For more information on screed testing, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

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February 18, 2020 admin

Non-Destructive Testing On Reinforced Concrete Tanks

Infrastruct was contacted by the Consulting Engineers on a project to carry out non-destructive testing on a new, above ground reinforced concrete tank. The tank was designed to retain sewage as part of the treatment process and the Engineers needed confirmation that there were no hidden defects or anomalies within the walls of the structure.

Random 1200x1200mm test areas were selected on the walls of the structure and the following testing was carried out:

1. GPR surveys on selected sections of the concrete walls to identify the location of embedded reinforcement and scan for evidence of hidden voids within the walls.
2. Check the in-situ concrete integrity using the MIRA pulse echo tomographer to generate cross section images of the concrete walls to examine the concrete for internal voids or other hidden defects within the concrete.
3. Water permeation testing (GWT) to assess the permeability of the finished concrete tank walls (permeation of water under an applied pressure of 100kPa).
4. Ultrasonic Pulse Velocity (UPV) measurements to evaluate the depth of selected cracks.
5. Crack width measurements using a microscope to check the width of selected cracks.

Photographs 1, 2 and 3 below show the test equipment in use on the walls of the tank.

The results of the testing was recorded on-site by our Engineers and a comprehensive report, with interpretation of all the results, was prepared for our Client.

For more information on non-destructive testing of concrete structures, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

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January 10, 2020 admin

Reinforcement Scanning On Concrete Slats & Slabs

In late 2019, Infrastruct was instructed by the Contractor building a large Slatted Unit in the Midlands to carry out a covermeter survey to confirm the presence of embedded reinforcement in each concrete slat and slab forming the Slatted Unit.

Infrastruct used a combination of the following equipment to confirm the presence of reinforcement in each slat and slab in the Slatted Unit:

1. Proceq PM-650 Covermeter with the extension handle for line scanning on the concrete surface
2. Hilti PS-1000 X-Scan GPR system to locate reinforcement deep within certain slabs.

Photographs 1 and 2 below the Proceq PM650 and Hilti PS-1000 being used to scan the top surface of the concrete elements to locate and confirm the presence of embedded reinforcement.

The results of the testing was recorded on-site by our Engineer and a comprehensive report, with interpretation, was prepared for our Client.

For more information on testing concrete elements and structures for agricultural use, please contact Dr Thomas Callanan in Infrastruct Asset Management Services Limited.

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