Classification of Traffic Signals Traffic signals are the control devices which alternately direct the traffic to stop and proceed at intersections using red and green traffic light signal automatically. The signals are classified into the following types: Traffic Control Signals Fixed time signals Manually operated signals Traffic actuated (automatic) signals Pedestrian signals Special traffic signals … Read more
Causes of Stone Deterioration The various natural agents such as rain, heat, etc. and chemicals deteriorate the stones with time. 1.Rain Rain water acts both physically and chemically on stones. The physical action is due to the erosive and transportation powers and the latter due to the decomposition, oxidation and hydration of the minerals present … Read more
Pipes for Water Supply System Pipes which are commonly used in water supply system are given below. Cast Iron (CI) Pipes Steel Pipes Galvanized Iron (GI) Pipes Copper Pipes Plastic or Polythene or PVC pipes Asbestos Cement (AC) Pipes Concrete Pipes 1. Cast Iron Pipes These pipes are most commonly used in water distribution system … Read more
Technical Terms Used in C.P.M [Critical Path Method] The following technical terms need be understood clearly before constructing the CPM network 1. Activity An activity is a part of the project denoted by an arrow on the network. The tail of the arrow indicates the start of the activity whereas the head indicates the end … Read more
Defects in Paint Work The defects which are commonly found in paint work are as follow. 1. Blistering Formation of bubbles like shapes on the painted surface is known as blistering. The primary cause of this defect is water vapor. When water vapor trapped under the paint layer, it creates bubbles under the film of … Read more
Economy in Formwork Construction The total cost of concrete construction work includes the cost of formwork also. Construction of formwork involves considerable expenditure in terms of cost of material, cost of labour for fabrication, erection and removal of formwork and time element. In case of buildings, the cost of formwork may range between 30 to … Read more
Factors Affecting Selection of Floor Tiles There are so many alternative types of tiles for floors and we must choose the type of tile to be used with great care. The appearance of a finished building will be very much influenced by the flooring material used and at the same time, the floor material should … Read more
Strength and Modulus of Weathered Rock from SPT Values In the weathered rock it is difficult to drive the split sampler to the full specified depth as in soil. Hence we may estimate the strength and elastic modulus values of weathered rock by driving the spt apparatus for a fixed number of blows and find … Read more
Placing of Concrete in Hot Weather For normal concreting operations the temperature of concrete should vary between 150C to 250C to enable it to attain its full ultimate strength within 28 days. In case concreting is carried out in extreme hot weather conditions, the rate of hydration of cement gets accelerated and the water in … Read more
Main fire protection requirements for multi-storied buildings can be summarized as under. 1. Structure The structural framework can be in R.C.C or steel. In case of steel structure, it will be necessary to encase the structural components by tiles, concrete or bricks. The fire resistance of load bearing walls, columns and beams should not be … Read more