INFLUENCE OF SALT WATER IMMERSION ON THE OMPRESSIVE STRENGTH OF A HOT ROLLED SHEET MIXTURE

• Main Author: Oktarizal, Buyung
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/2920
• Institution: Institut Teknologi Bandung

The long-term performance of a bituminous mix is significantly influenced by its durability i.e. its ability to resist the detrimental effects of adverse climatic conditions. In the laboratory, the resistance of the mix to water damage is normally determined by evaluating the effect of a relatively short period of immersion in water at elevated temperature on some indicator of the mix strength. However evaluation of durability in this way may not reflect fully the consequences of long term exposure to water. At some locations on the coastal plains of Indonesia, bituminous material is in contact with salt water for relatively long periods of time. The influence of salt water on the durability of bituminous mix has not been widely researched. In the research described in this thesis samples of HRS Class A mix were immersed in salt water at ambient temperature and at two concentration (5% and 10%) for periods of 10, 20, 40, 60 and 90 days and the consequences for uniaxial compressive strength and resistance to permanent deformation evaluated. Compressive strength was determined on Marshall-size samples and deformation resistance in the wheel tracking test. For control purposes, the same tests were performed on specimens immersed in fresh water for identical time periods. The HRS mix investigated complied In all respects with Bina Marga design criteria and in particular had an index of retained stability of 88%. Specimens immersed in fresh water exhibited a slight but progressive loss in strength up to 60 days immersion; there was no further loss in strength when the immersion period was extended to 90 days. Specimens immersed in salt water gained in strength at immersion periods of 10 and 20 days. However, after 40 days immersion, strength was reduced by 17.4% and 20.3% (5% and 10% salt respectively) as compared with a loss of 13.2% for specimens immersed in fresh water. After 90 days Immersion, the strength of specimens immersed in water containing 5% and 10% salt was reduced, respectively, by 32.9 and 39.1%. Considering strength loss in terms of the second durability index proposed by Craus et al (1981) immersion in either fresh or salt water over a 90-day period results in a durability loss. However the loss is greater when the mix is immersed in salt water and is significantly higher at the 10% salt concentration. In the wheel tracking test, the rate of deformation of specimens immersed in salt water for long periods of time is higher than that of specimens immersed in fresh water; the higher the salt content the greater the rate of deformation .