Research
Integrated Approach to Investigation of Effect of Salt on Bitumen Properties and Stability of Flexible Pavement in Coastal Areas
Demand for modifications is increasing throughout the world parallel to develop the existing highway materials to fulfill the increasing demand of vehicles. Some materials produce good effect and enhance the strength as well as qualities of bitumen. On the other hand, some materials are responsible for adverse effect on the bitumen. In saline areas like coastal regions, the salt plays a significant role on the bituminous pavement. In this area, the most of the highways come to contact with salts content materials. In present study, the focus was given to find the various effects of salts on bitumen and bituminous mixers. A number of samples were prepared with addition of sodium chloride with respect to 2%, 4%, 6%, 8%, and 10% weight of bitumen. To determine its behavior and suitability, a variety of tests such as penetration test, softening point test, flash point and fire point test, ductility test, specific gravity test, solubility test etc. were conducted by standard ASTM method. It was observed from laboratory test that the penetration and specific gravity value are gradually increased and ductility, flash point, fire point, and softening point was gradually decreased due to the increase of salts content in a bituminous mix. To observe the effect of salt on stability of flexible pavement Marshall Mix design method was used with varying percentage of salt content. The stability value of bituminous mixes was decreased with increase the salt content in bitumen. From the consideration of stability, maximum 2% salt in bitumen can be allowed for road construction.
Effect of Size on Compressive Strength of Concrete Cylinder Specimens using Sand and Sulfur Cap
In the majority of structural concrete design, the compressive strength is obtained from testing of 150x300 mm concrete cylinders under standard laboratory controlled conditions with different capping system. Some testing machines are unable to produce the force needed to break high-strength 150x300 mm concrete cylinders. If 100x200 mm cylinders are to be used in quality assurance testing, the relationship between fc4 and fc6 needs to be understood in order to ensure that concrete with sufficient strength is provided. 100x200 mm cylinders are lighter and can easily be handled, collection of quality control and assurance specimens would be easier for contractors and inspectors. This research work was born from the need to determine a correlation between the strength of the standard size 150x300 mm and 100x200 mm cylindrical specimen. A total 72 no. of 100x200 mm and 150x300 mm cylinders were tested according to ASTM. Cylinders prepared by sand and sulfur capping reveals a little difference in the strength level, 150x300 mm and 100x200 mm sulfur capped cylinders shows 23% and 21% higher strength than sand capped cylinders and 100x200 mm cylinder gives 39% higher strength than 150x300 mm cylinder.
