Cross Sectional Elements of A Pavement The characteristics of cross-sectional elements are important in highway geometric design because they influence the safety and comfort. The 7 basic cross sectional elements of a highway pavement are Camber Width of Carriage way Kerb Road Margin Width of Formation Right of Way (ROW) 1.Camber Camber or cant is … Read more
Pavement Surface Characteristics For safe and comfortable driving four aspects of the pavement surface are important; The friction between the wheels and the pavement surface, Unevenness of the road surface, The light reflection characteristics of the top of pavement surface, and Drainage to water. 1.Friction Friction between the wheel and the pavement surface is a … Read more
Selection of Hill Road Alignment The main factors to be considered while deciding the alignment of hill roads, are given below. 1.Length The cost of construction of a hill road per kilometer length is comparatively very high. It should therefore be ensured that length of the road connecting two stations should be minimum possible, adopting … Read more
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
In order to determine the suitability of a particular soil it is essential to know the proportion of each material in the soil and also whether the particular material possesses the properties required of it. For instance, a road soil that is 95 percent sand will not cohere, and clay that does not possess the … Read more
The following are the differences between bitumens and tars. The weathering properties of bitumens are superior to those of tars. Generally greater deterioration is produced in tar than in bitumen when exposed to equal weather conditions. Bitumens have a better durability and resistance to weathering than tars. Tars are more susceptible to temperature changes than … Read more
There are a number of factors which are to be considered while selecting the alignment of roads. These factors also vary according to the type of roads and the areas through which these roads pass. The factors which control alignment of roads in plain areas as under: 1. Class & Purpose The alignment of the … Read more
WBM Road Construction Procedure Construction of water bound macadam road involves the following 6 basic steps as given below. Preparation of sub-grade Preparation of sub-base Preparation of base Preparation of wearing course Preparation of shoulders Opening to traffic Step – 1 (Construction of Sub-grade) Sub-grade act as a cushion for other layers i.e. In order … Read more
Different Classes of Urban Roads The urban road are classified as under Express way Arterial streets Sub-arterial streets Collector streets Local streets 1. Expressways The city roads which are reserved for motor traffic with full or partial control access and are provided with grade separation at intersections are called expressways. These are generally constructed to … Read more
Sleepers The members which are laid transverse to the rails, to support the rails and to transfer the loads from rails to the ballast, are called sleepers. Functions of Sleepers The main functions of sleepers in a railway track are as under: These hold the rails to proper gauge in all situations i.e. exact gauge … Read more