Engineering key Point

Physical Tests on Cement (a) Soundness Test: It is conducted by sieve analysis. 100 gms of cement is taken and sieved through IS sieve No. 9 for fifteen minutes. Residue on the sieve is weighed. This should not exceed 10 per cent by weight of sample taken. (b) Setting Time: Initial setting time and final setting time are the two important physical properties of cement. Initial setting time is the time taken by the cement from adding of water to the starting of losing its plasticity. Final setting time is the time lapsed from adding of the water to complete loss of plasticity. Vicat apparatus is used for finding the setting timesVicat apparatus consists of a movable rod to which any one of the three needles shown in figure can be attached. An indicator is attached to the movable rod. A vicat mould is associated with this apparatus which is in the form of split cylinder. Before finding initial and final setting time it is necessary to determine water to be added to get sta

Chapter one INTRODUCTION Curves are provided whenever a road changes its direction from right to S (vice versa) or change sits alignment from up to down (vice versa). Curves are a critical element in the pavement design. They are provided with a maximum speed limit that should lie followed very strictly. Following the speed limit becomes essential as the exceed in speed may lead to the chances of the vehicle becoming out of control while negotiating a turn and thus increase the odds of fatal accidents. Also, it is very necessary that appropriate safety measures be adopted at all horizontal and vertical curves to make the infrastructure road user friendly and decrease the risks of hazardous circumstances. The center lines of highways and railroads consist of a series of straight lines connected by curves. The curves of fast traffic are normally circular, although spiral curves may be used to provide gradual transitions to or from the circular curves. There are different kind