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
Quality Control of Concrete Construction Quality of concrete construction on site can be accomplished in three distinct stages as follow Quality control before concreting Quality control during concreting Quality control after construction Stage-1 (Quality Control Before Concreting) This stage of quality control consists of two steps. Checking of specification requirements regarding excavation, forms, reinforcement and … Read more
No single stone can satisfy all the below mentioned quality requirements. For example, strength and durability requirement contradicts ease of dressing requirement. Hence it is necessary that site engineer looks into the properties required for the intended work and selects the stone accordingly. Requirements of Good Building Stones The following are the quality requirements of … Read more
Honeycomb Repair in Concrete Surface Honeycomb and larger surface voids require procedures resembling those for typical concrete repairs. But there’s nothing typical about the recommended approaches to repairing these voids. They vary greatly. While repairing voids or honeycomb in concrete surface, the most common question that arises is what should be the thickness of the … Read more