Scaffolding When temporary structures are provided to support platform for workmen, structural material and appliances required during construction at raised height (normally more than 1.5 m) it is called scaffolding. Applications of Scaffolds Scaffolding is necessary in following situations. To support the working platforms where masons can stand and carry on their duties such as … Read more
HOLLOW CONCRETE BLOCK MASONRY Concrete blocks having core void area larger than 25% of the gross area is termed as hollow concrete blocks. These blocks are manufactured in different shapes and sizes as shown in the following figure. Some of the standard sizes of hollow concrete blocks are as follow. Standard size hollow concrete block … Read more
Values of Safe Bearing Capacity The safe bearing capacity of soil should be determined on the basis of soil test data or by performing some field test such as Standard penetration test or Plate load test etc. However, in the absence of soil test data, the values of safe bearing capacity (S.B.C) as given in … Read more
Sources of Defects in Brick Masonry There are 4 primary reasons that cause defects in brick masonry work. These are as follows. Sulphate Attack Crystallization of Salts from Bricks Corrosion of Embedded Iron or Steel Shrinkage on Drying 1. Sulphate Attack The common forms of defects due to sulphate attack are Chipping and spalling of … Read more
Laboratory Vane Shear Test of Soil Aim To determine shear strength of clay soil using laboratory vane shear apparatus. Theory In soil, shear strength is contributed by the two properties. Cohesion, and Angle of internal friction In pure clays the shear resistance due to internal friction is negligible. Hence, the complete shear strength in clays … Read more
Types of Failures of Flexible Pavement Flexible pavement consist of different layers such as, Sub-grade Sub-base course Base course and Surface course If any one of the above mentioned layers becomes unstable or weak then it will result in failure of flexible pavement. Therefore it is very important to design and construct each layer with … Read more
Types of Bonds in Brick Masonry Brick masonry is built with bricks bonded together with mortar. For temporary sheds mud mortar may be used but for all permanent buildings lime or cement mortars are used. The various types of bonds generally used in brick masonry are Stretcher bond Header bond English bond and Flemish bond … Read more
Types of Quality Control One of the most important tasks of the supervision during the execution of a road contract is technical quality control, i.e. control as to whether the materials and work supplied by the Contractor meet the technical requirements in the contract specifications. There are two types of quality control, which are described … Read more
Factors Affecting Pavement Design Several factors affect pavement design, the most important being wheel load. Since pavements are designed to take moving loads, slow moving loads and static loads can be detrimental to the pavement. Temperature also influences pavement design especially the frost action which is very important in cold countries. There are many factors … Read more
Tests on Aggregate Aggregate plays an important role in pavement construction. Aggregates influence, to a great extent, the load transfer capability of pavements. Hence it is essential that they should be thoroughly tested before using for construction. Not only that aggregates should be strong and durable, they should also possess proper shape and size to … Read more