Here we are going to discuss the construction of the wbm and wmm roads in brief. Wbm road construction procedure construction of water bound macadam road involves the following 6 basic steps as given below. Wbm water bound macadam and wmm wet mix macadam are used for road construction in base course layer. Nosegregation of 18 apply binding material, wherever required, in a similar fashion as screening. Whether it is a flexible pavement or a rigid pavement, it has a wbm at its base. Wbm road construction procedure for wbm road highway engineering. If the wbm roads are maintained properly and from time to time, it can resist load of traffic of about 900 tonnes per lane per day. Wbm road construction procedure for wbm road highway. Bitumen road construction consists of various steps such as preparation of base course, application of bituminous coat, placement of bituminous mix, rolling and check for quality etc. Water bound macadam wbm shall consist of clean, crushed coarse aggregates. In the construction of wbm road no skilled labours are required.
This technique in present day is used as given below. Wbm stands for water bound macadam which is the most commonly used road construction procedure for over more than 190 years. Pioneered by scottish engineer john loudon mcadam around 1820 macadam is a type of road construction. The broken stones of base and surface course,if any are bound by the stone dust is presence of moisture is called wbm. In this video i will till you about water bound macadam and its general specification and required tests of wbm. They are constructed from locally available materials.
Preparation of subgrade preparation of subbase preparation of base preparation of wearing course preparation of shoulders opening to traffic step 1 construction of subgrade subgrade act as a cushion for other layers i. Hard trap stones of size from 65mm to 75 mm are spread out on the well. Bitumen road construction consists of various steps such as preparation of base course, application of bituminous. This document is not intended to be comprehensive and therefore does not provide information on all construction activities. The existing surface is prepared by removing the pot holes or rust if any. This procedure manual provides a guide to the correct onstruction c practices and procedures for use on road contracts by the roads and highways department. The construction cost of wbm road is comparatively low. Water bound macadam wbm road construction procedure duration. Difference between wbm and gsb in road construction. The water bound macadam road construction technique was given by the john macadam. Wbm stands for water bound macadam, and the term wbm road was derived in the memory of an engineer by name macadam who designed and formulated this.
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