Recently Completed Projects
Ultrasonic pulse velocity tests carried out by direct and in-direct methods on RCC structure.
Typical photos of UPV testing carried for condition assessment of concrete structures
Typical photos of UPV testing carried for condition assessment of concrete structures
Typical photos of UPV testing carried for condition assessment of concrete structures
Typical photos of UPV testing carried for condition assessment of concrete structures
Core sampling for Strength Assessment of Concrete Structures
The core samples collected can be tested for compressive strength, chemical analysis, petrography examination etc. Normally 75mm to 100mm diameter core is used for extraction of core samples for compression testing. The cores should have a length/diameter ratio between 1.0 and 2.0. Cores were extracted by means of rotary cutting tool with diamond bits. The base should have solid support to prevent relative movement. Water supply should be continuous to lubricate the cutter and applied pressure should be uniform.
Concrete Core Extraction in Progress
Concrete Core Samples
The collected samples are dressed and the dressed core samples were tested for compressive strength
Sizing of specimen using diamond saw concrete cutter
Dressed Concrete Core
Compression testing of dressed core samples
Field testing for Assessment of Corrosion in Reinforced Concrete Structures
Half Cell Potential Survey
Corrosion being an electrochemical phenomenon, the electrode potential of steel rebar with reference to a standard electrode undergoes changes depending on corrosion activity. A systematic survey on well defined grid points gives useful information on the presence or probability of corrosion activity. The gird points used for other measurements, namely, Rebound Hammer and UPV can be used for making the data more meaningful. The common standard electrode used for concrete is the Copper-Copper Sulphate Electrode. The measurement consists of giving an electrical connection to the rebar and observing the voltage difference between the rebar and a reference electrode in contact with concrete surface. A systematic “potential mapping survey” is considered to be more useful for on-site identification of the corrosion state of the rebars.
Copper-Copper Sulphate Electrode for potential measurement in rebar
Half-cell potential measurement on an actual structure
The measurement consists of giving an electrical connection to the rebar and observing the voltage difference between the rebar and a reference electrode in contact with concrete surface.
Half-cell potential measurement on a corroded structure
Large scale NDT test specimen for research
The test specimen is a reinforced concrete specimen, designed and constructed at the CSIR-Structural Engineering Research Centre (SERC), exclusively for the data generation and validation of different NDT techniques.
- It consists of two slabs of sizes 4.15m x 4.15m (bottom slab) and 3.0m x 3.0m (top slab with cantilever projection at one end) with beams and columns.
- The entire block is supported on four pedestals at a height of 1.2m to have access for the bottom slab.
- The top slab is made with two different thicknesses (150mm and 250mm) and bottom slab with three different thicknesses (150mm, 300mm and 400mm) for validating the thickness measurements using NDT methods. At the edge, the slab is tapered.
- Top slab is provided with construction joints, different sizes and shapes of honeycombs, PVC conduits, cracks for their identification and quantification.
- Bottom slab is provided with bolt holes, PVC inserts and conduits to locate and quantify the defects.
- Both the slabs have various reinforcement ratios to locate the position of the bars, spacing etc.
- Beams are provided with different diameter of reinforcements with different spacing of shear reinforcements and different cover thickness.
- Beams are provided with ducts to study the grouting problems in prestressing ducts. Columns are provided with different diameter of reinforcements with different spacing of lateral ties and different cover thicknesses.
Scale NDT Test Specimen
Details of inserts and pipes in Second floor slab
Large scale NDT test specimen for research
REFLEXW and RADAAN are the programs used for the processing and interpretation of reflection and transmission ground penetrating radar (GPR) data collected from the specimens using manual scanning or the automated scanner.
The 3D data-interpretation module is used for displaying x-,y- or z-slices
SERC NDT Specimen Data
Raw, Migrated and 3D Plot
The advantage of GPR compared to Ultrasonic pulse echo technique is that larger surface area can be examined in short time because of the continuous measurements along a surface
Top Floor showing the absence of reinforcements, honeycombs and PVC
Oscilloscope, Wiggle and Linescan Plot showing Embedded Steel Plate