Factors Affecting Transportation The success of transportation engineering depends upon the co-ordination between the three primary elements, namely the vehicles, the roadways, and the road users. Their characteristics affect the performance of the transportation system and the transportation engineer should have fairly good understanding about them. This post elaborated salient human, vehicle, and road factors … Read more
Processing of Borrow Area Soils / Backfill Materials The construction of subsurface structures often requires the construction of elements of the structure within or upon large masses of backfill. The proper functioning of these elements are often critically affected by adverse behavioral characteristics of the backfill. Behavioral characteristics are related to material type, water content … Read more
What is Contraction Joint? A contraction joint is one in which the two concrete surfaces are free to move away from one another as a result of shrinkage or thermal movement. Relative movement in the plane of the joint is prevented. Why to Provide Contraction Joint? As concrete hardens and dries out, it shrinks. Unless … Read more
Aggregates for Asphalt Concrete The amount of aggregates for asphalt concrete mixtures is generally 90 to 95 percent by weight and 75 to 85 percent by volume. Aggregates are primarily responsible for the load supporting capacity of a pavement. Aggregate has been defined as any inert mineral material used for mixing in graduated particles or … Read more
Essential Properties of Asphalt Concrete Mix design methods and design requirements form an essential part for all asphalt concrete mixtures. The agency or authority responsible for paving construction (Department of Transportation) usually establishes the mix design method and design requirements. Once these are established, it becomes the responsibility of the Contractor/Producer and his technician to … Read more
Joints in Rigid Pavement Provisions of joints are necessitated due to: 1) Expansion, contraction and warping of concrete slabs resulting from temperature and moisture changes; 2) Facilitate a break in the construction at the end of day’s work or for any unexpected interruption to work progress; and 3) Construction of pavements in lanes of convenient … Read more
Failure of Rigid Pavement Failure in rigid pavement (or cement concrete pavement) can be identified by formation of cracks on the pavement surface. The two prime factors responsible for rigid pavement failure are Use of poor quality material Inadequate stability of the pavement structure Poor quality of material consist of following items Using soft aggregate … Read more
Failure of Flexible Pavement A typical flexible pavement consist of following 4 layers Soil subgrade Sub-base course Base course Surface or wearing course If due to any reason, any of the above mentioned layers loses its stability, it will lead to failure of the whole pavement. There are many types of failures of flexible pavement, … Read more
Definition – What is Bitumen Emulsion? Bitumen emulsion is a mixture of water & bitumen. Hey wait, we know that bitumen is a oil product and it cannot be mixed with water. That is why we add an emulsifier (a surface active agent) with water before adding bitumen. Addition of emulsifier with water facilitates breaking … Read more
Types of Rollers Depending upon the project requirement and soil to be compacted, different types of rollers are used for compaction work. The various types of rollers which are used for compaction are: Cylindrical Rollers Sheepsfoot Rollers Pneumatic tyred Rollers Smooth wheeled Rollers Vibratory Rollers Grid Rollers The following types of road rollers are generally … Read more