NOT STUDY ON THE COMPRESSIVE STRENGTH OF PETROCHEMICAL SOAKED CONCRETE

Abstract

Concrete is a major construction material for a wide variety of applications. It has been used since a century for the construction of structures which are in direct contact with petrochemicals. Their economic use in these structures justify the promotion of further research work into the use of concrete on a wider scale. Compressive strength is employed as a functional material representative at the design stage. Changes in the material behaviour at the microstructural level resulting from petrochemical interaction can be expected to translate in to changes in mechanical properties of concrete. The important aspect of the present investigation is to monitor the compressive strength of concrete which is in direct contact with petrochemicals. To have good simulation the specimens used in this study were soaked in petrochemicals. Petrochemicals used are high speed diesel oil and Kerosene oil. Further to monitor the progressive changes in properties and quality of concrete, Nondestructive test (NDT) study was taken up. The major strength relating and economical NDT methods which are used in the investigation are the schmidt's rebound hammer method and ultrasonic pulse velocity test. Statistical regression models relating the corresponding NDT parameters and direct compressive strength were developed. To obtain the compressive strength more accurately from the NDT parameters, a muliiple regression correlation model was also developed. The experimental programme was carried out in different petrochemical environments i.e., H.S.D. oil and Kerosene oil. For purposes of comparison tests CC) were also conducted on specimens cured in water for various periods of exposure (3, 7, 14 and 28 days). Both fresh concrete and hardened concrete specimens were subjected to these exposure conditions. It was observed that fresh concrete is more affected by petrochemicals when compared to hardened concrete. Among the two petrochemicals Kerosene was more effective than H.S.D. oil in hindering the rate of strength gain of fresh concrete. To assist, the study and interpretation of physical results, X-ray diffraction analysis was done. X-ray diffraction studies reveal that although the chemical compounds formed in concretes under petrochemical environment are the same as those due to hydration of cement in concrete, their percentages differ significantly. The differences in relative amounts of weak and strong compounds formed help in explaining the behavioral changes of concrete.