Concrete is the main component in construction of civil infrastructure. However, deformation in concrete such as crack or void may occur either on its early stage or during its usage. Hence, concrete evaluation is a need in determining its strength and quality status. Direct Ultrasonic Pulse Velocity (UPV) method is the most common non-destructive measurement adopted to assess the condition of concrete structure. However, problems arise when there is limited accessible surface to probe the ultrasonic transducers. Hence, this project is undertaken to analyse ultrasonic NDT by utilising different arrangement of sensors on tested concrete. The simulation of the homogenous and non-homogenous concrete system will be done by using COMSOL Multiphysics software. The output signal obtained from the simulation is used for the image reconstruction by using the sensitivity mapping technique. The results are then validated by assessing the actual model of concrete structure using direct, indirect, and semi-direct UPV probing in order to get the exact location of defects. Preliminary result shows that proposed method can help to improve the defects determination in concrete structure.

Electrical capacitance tomography (ECT) is categorized as a soft-field sensor which is non-invasive and non-intrusive instrument that can provide the visualization of cross-sectional distribution of any kind of multiphase flow. ECT would help in understanding the gas-solid flow interaction. This research is conducted to overcome some difficulties in measurement of gas-solid flows that exist in multiphase flows in pipelines or vessels such as the sedimentation of the solid and the velocity of the solid particles. Hence, the characterization of gas-solid two-phase flow by implementing an ECT system is necessary. Three objectives are set for this research which are the determination of an optimum frequency and amplitude for capacitance measurement of Poly-methyl methacrylate (PMMA) material by ECT system, the determination of the average solid velocity in gas-solid two-phase flow through cross-correlation method using Parseval’s theorem, and image reconstruction based on eight ECT sensors using Linear Back Projection (LBP) algorithm. This paper concise the theory of ECT system, existing works, proposed methodology, and the expected results.