Aging of Bitumen Binders Bitumen, like any organic matter, is affected by factors like presence of oxygen, ultraviolet rays and changes in temperature. These factors are responsible for hardening of bitumen. Hardening results in Decrease in penetration value Increase in softening point temperature and Increase in penetration index (PI). For increased life of bituminous pavement … Read more
Quality Assurance for Cement Plastering Plastering is a process of applying one or more coats of mortar to a concrete surface, brickwork, stone masonry or lathing. It must be durable such that it resists the penetration of moisture and should be able to weather uniformly. It should also be pleasing in appearance. These properties depend … Read more
Factors influencing Corrosion of Reinforcement In reinforced cement concrete construction the corrosion of reinforcement takes place due to the presence of chlorides and sulphates beyond a critical limit and when sufficient alkalies is not obtained within the concrete to maintain steel in a positive condition. The following factors are responsible for corrosion of steel reinforcement … Read more
Bricks used in construction industry can have the following defects. So before using the bricks, it should be inspected properly for presence of any of the following defects. Different Types of Defects Found on Bricks 1. Over-burning of Bricks Bricks should be burned at temperatures at which incipient, complete and viscous vitrification occur. However, if … Read more
Performance Requirements of Needle Vibrators The operational frequency of vibrator when operated in air (i.e. when not immersed in concrete) shall not be less than 100 Hz and should preferably be higher. For different sizes of needle, the optimum operational amplitude when operated in air, measured in the middle of the vibrating needle should satisfy … Read more
Aim This test method describes the procedure for determining the drying shrinkage or change in length of concrete specimen due to changes in moisture content. Apparatus A length measuring apparatus incorporating a dial gauge capable of measuring the length accurately to 0.005 mm. (see fig shown below) Drying oven capable of maintaining a temperature of … Read more
Properties of Fresh Concrete Concrete remains in its fresh state from the time it is mixed until it sets. During this time the concrete is handled, transported, placed and compacted. Properties of concrete in its fresh state are very important because the influence the quality of the hardened concrete. The fresh concrete has the following … Read more
QUALITY REQUIREMENTS OF COMMON BURNT CLAY BUILDING BRICKS 1. General Quality Bricks shall be free from cracks and flaws and nodules of free lime. Bricks shall have smooth rectangular faces with sharp corners Bricks shall be uniform in colour Frog size of a hand moulded brick having height of 90 mm or 70 mm shall … Read more
Basic Components of a Building A building consists of following basic components. 1. Foundation A foundation is necessary to evenly distribute the entire building load on the soil in such a manner that no damaging settlements take place. Hence, the foundations need to be constructed on good/solid ground. 2. Plinth A plinth is normally constructed … Read more
Tremie Method of Under Water Concreting Tremie method is the most acceptable method of concreting under water. In this method a tremie pipe is inserted in the water up to the point where concrete is going to be placed. Generally the diameter of a tremie pipe varies from 20 cm to 30 cm. Depending upon … Read more