J. Rhazi

Bio: J. Rhazi is an academic researcher. The author has contributed to research in topics: Ground-penetrating radar. The author has an hindex of 1, co-authored 1 publications receiving 47 citations.

Test Method for Evaluating Asphalt-covered Concrete Bridge Decks Using Ground Penetrating Radar

Abstract: This paper presents the synthesis of an experimental investigation concerning con- crete corrosivity and delamination efiects on electromagnetic wave propagation in reinforced con- crete. It demonstrates that the data analysis procedure, proposed in the ASTM D6087 \Standard Test Method for Evaluating Asphalt-Covered Concrete Bridge Decks Using Ground Penetrating Radar (GPR)", is not always valid. A novel methodology of GPR data processing that allows the detection of areas of high probability of rebar corrosion in concrete is presented.

Signal processing of GPR data for road surveys

Abstract: Effective quality assurance and quality control inspections of new roads as well as assessment of remaining service-life of existing assets is taking priority nowadays. Within this context, use of ground penetrating radar (GPR) is well-established in the field, although standards for a correct management of datasets collected on roads are still missing. This paper reports a signal processing method for data acquired on flexible pavements using GPR. To demonstrate the viability of the method, a dataset collected on a real-life flexible pavement was used for processing purposes. An overview of the use of non-destructive testing (NDT) methods in the field, including GPR, is first given. A multi-stage method is then presented including: (i) raw signal correction; (ii) removal of lower frequency harmonics; (iii) removal of antenna ringing; (iv) signal gain; and (v) band-pass filtering. Use of special processing steps such as vertical resolution enhancement, migration and time-to-depth conversion are finally discussed. Key considerations about the effects of each step are given by way of comparison between processed and unprocessed radargrams. Results have proven the viability of the proposed method and provided recommendations on use of specific processing stages depending on survey requirements and quality of the raw dataset.

Methodology for Assessing the Probability of Corrosion in Concrete Structures on the Basis of Half-Cell Potential and Concrete Resistivity Measurements

Abstract: In recent years, the corrosion of steel reinforcement has become a major problem in the construction industry. Therefore, much attention has been given to developing methods of predicting the service life of reinforced concrete structures. The progress of corrosion cannot be visually assessed until a crack or a delamination appears. The corrosion process can be tracked using several electrochemical techniques. Most commonly the half-cell potential measurement technique is used for this purpose. However, it is generally accepted that it should be supplemented with other techniques. Hence, a methodology for assessing the probability of corrosion in concrete slabs by means of a combination of two methods, that is, the half-cell potential method and the concrete resistivity method, is proposed. An assessment of the probability of corrosion in reinforced concrete structures carried out using the proposed methodology is presented. 200 mm thick 750 mm × 750 mm reinforced concrete slab specimens were investigated. Potential E corr and concrete resistivity ρ in each point of the applied grid were measured. The experimental results indicate that the proposed methodology can be successfully used to assess the probability of corrosion in concrete structures.

Systems and methods for asphalt density and soil moisture measurements using ground penetrating radar

Abstract: Systems and methods for ground penetrating radar for determining thickness, density and moisture are therefore provided. According to an embodiment, a ground penetrating radar (GPR) system comprises a system controller configured to produce an electromagnetic signal for signal penetration of a pavement material. Further, the GPR system comprises a frequency modulated continuous wave controller. Further, the GPR system comprises an ultra wide band (UWB) antenna coupled to the system controller, wherein the UWB antenna is configured to transmit the produced electromagnetic signal to the pavement material and receive the electromagnetic signal as a reflection from the pavement material. Further, the system controller is further configured to receive the electromagnetic signal from the UWB antenna.