Core Recovery and RQD (Rock Quality Designation) The easiest way to characterize the amount of material recovered during rock coring is to calculate “core recovery” as the amount (i.e. length) of recovered material divided by the total length of the core run (presented as a percentage). Rock Quality Designation (RQD) is a modified core recovery … Read more
How to Select Soil & Rock Properties for Engineering Design? A rational approach for selecting soil & rock properties for engineering design can be summarized as a logical twelve-step procedure that covers the 3 primary stages i.e. Site Investigation and Field Testing, Laboratory Testing and Interpretation, and Engineering Design This step-by-step process is presented on … 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
Fly Ash Fly ash or pulverized fuel ash (PFA) is the residue from the combustion of pulverized coal collected by mechanical or electrostatic separators from the flue gases or power plants. It constitutes about 75 per cent of the total ash produced. The properties and composition of fly ash vary widely, not only between different … Read more
Quality Requirements of Drinking Water Parameter Requirements (Desirable Limits) Undesirable effect when outside permissible limit Permissible limit in the absence of alternate source ESSENTIAL CHARACTERISTIC pH 6.5 – 8.5 Beyond this range the water will affect the mucous membrane and/or water supply system No relaxation Colour (Hazen units), maximum 6.5 – 8.5 Above 5, consumer … Read more
Depth of Soil Exploration The object of site exploration is to provide reliable, specific and detailed information about the soil and ground water condition of the site which may be required for a safe and economic design and execution of the engineering work. Dr. B.C. Punima Generally soil exploration should be advanced to a depth … 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
ABSOLUTE VISCOSITY TEST OF BITUMEN Reference IS: 1206 (Part 2) – Method for Testing Tar and Bitumen Materials: Determination of Absolute Viscosity Test Equipment The following testing equipment is needed to measure absolute viscosity of viscosity graded paving bitumen (IS:73-2006) at 60 C in accordance with IS:1206 (Part 2) (similar to ASTM D 2171), which … Read more