Bitumen is defined as “A viscous liquid, or a solid, consisting essentially of hydrocarbons and their derivatives, which is soluble in trichloro-ethyelene and is substantially nonvolatile and softens gradually when heated”. It is black or brown in colour & possesses waterproofing and adhesive properties. It is obtained by refinery processes from petroleum, and is also … Read more
Purpose Water retentivity of mortar is the ability of mortars to retain water against suction and evaporation in general. It is indirectly a measure of the workability of mortars. Apparatus The apparatus used for this test consists of a water aspirator or other source of vacuum controlled by way of a three way stopcock to … Read more
Objective Determination of water absorption and bulk density of all ceramic tiles Apparatus Oven – capable of maintaining temp of about 1100c Balance – accurate to 0.01% of the mass of test specimen Water bath Desiccators Chamois leather Wire basket Preparation of Test Sample A test sample consists of 10 numbers of whole tiles. If … 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
Objective Determination of modulus of rupture and breaking strength of a whole tile by means of three point loading, the central point being in contact with the glazed surface of the tile. Apparatus Drying oven having capacity of 110±50C Recording gauge – Accurate to 2% Two support cylindrical rods – These rods are made up … Read more
A potable water is one that is safe to drink, pleasant to taste and usable for domestic purposes. Contaminated water is one that contains the bacteria which causes diseases. Polluted water is one that contains substances which are undesirable or unfit for drinking or domestic use. Drinking water must be free from: Disease producing organisms … Read more
Plastics are nothing but synthetic organic high polymers. It is important to know the general outstanding properties of plastics to make best use of this an engineering material. It should also be noted that each plastic material has its own peculiar properties to suit the various uses. Hence the success of plastic as an engineering … Read more
Aggregates influence the properties of concrete/mortar such as water requirement, cohesiveness and workability of the concrete in plastic stage, while they influence strength, density, durability, permeability, surface finish and colour in hardened stage. Field Tests for Aggregate 1. Surface Moisture Content & Absorption The surface moisture in the aggregate, influences the water cement ratio, strength … Read more
Surface Index of Aggregates Surface index of aggregates is another way to represent the specific surface of aggregate. This method was suggested by Murdock. Murdock provided some empirical numbers to represent the specific surface of different aggregates grading (as shown in the table below). Surface Index Values for Single Graded Aggregate TABLE-1 Sieve Size Within … Read more
Plastic shrinkage cracking (as shown below) is caused by rapid drying of the concrete surface. They can occur at any time of the year, from cooler low-humidity weather conditions to, in particular, hot weather conditions involving any one or a combination of high temperature, low humidity and wind. These types of cracks occur while the … Read more
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