STUDY OF INHOMOGENEOUS WITH ULTRASONIC TOMOGRAPHY ON CONCRETE BLOCK.

• Main Author: Herman
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/78497
• Institution: Institut Teknologi Bandung

Tomography is a technique of combination of cross sectional imaging from various measurement data, and in this study ultrasonic are used as the source, can be referred as ultrasonic tomography. Tomography computing algorithms that use in this research is ART (Algebraic Reconstruction Technique) and SIRT (Simultaneous Iterative Reconstruction Technique) The objective of this research is to study both algorithm and compare them to the several blocks, concrete block, gypsum block, and limestone block. The block for biaxial test was also made, where the testing of ultrasonic wave while biaxial load, the measurement itself is done in the same direction line with the tunnel opening. Imposition itself is done on two conditions, where the first condition the vertical stress of 8.5 MPa, and the horizontal stress 2.5 MPa, whereas for second condition the hydrostatic stress of 10 MPa is given. The waves were generated and recorded with PUNDIT (Portable Unit non-destructive Digital Indicating Tester) that work with longitudinal stress 82 kHz frequency. The results showed reconstruction with SIRT show better results compared to ART, as shown by the wave velocity distribution in the contour color, where SIRT provide a more consistent color. One of the alternatives that can be used to evaluate the conditions in the rock are artificial neural networks (ANN), from experiments ANN can reproduce similar pattern of the data provided. Biaxial test was also conducted, physical testing and numerical, of the physical testing, ultrasonic wave velocity measurements performed to obtain the velocity distribution in biaxial loading conditions of the sample, while the numeric testing done based on the physical test and obtained the strength factor. The correlation between the speed of the wave and the strength factor is obtained, for the first condition the ultrasonic wave can not differentiating the value of tensile strength and compressive strength with coefficient of determination 3.2, whereas the second condition is obtained a stronger connection than the first condition with correlation coefficient 0.76, where an increase the value of strength factor is accompanied by increase the value of ultrasonic velocity.