CAUSES OF DISINTEGRATION OF CONCRETE The primary reasons that cause disintegration of concrete member are desribed below. 1. SULPHATE ATTACK Soluble sulphates are present in Ground water Soil Clay bricks Soluble sulphates react with Tricalcium Aluminate of cement I n the presence of moisture and form products which occupy much bigger volume than that of … Read more
Minimising Defects in Plastering Work Defects in plastering work can be minimised by following the below mentioned techniques. The brick and plastering work should be carried out by skilled masons in the best workmanship manner. Bond of brick work should be properly maintained. Efflorescence is removed by rubbing brushes on the damaged surface. A solution … Read more
BRICKWORK CHECK LIST FOR SITE ENGINEERS While on site, a site engineer must ensure that the brickwork is going on as per quality requirements. Some of the general requirements of quality of brickwork are mentioned below. Use this as a checklist while executing brickwork. The thickness of joint in brick masonry should not exceed 1 … Read more
Compounds of Cement About 90-95% of a Portland cement is comprised of the four main cement minerals, which are C3S, C2S, C3A, and C4AF, with the remainder consisting of calcium sulphate, alkali sulphates, unreacted (free) CaO, MgO, and other minor constituents left over from the clinkering and grinding steps. The four cement minerals play very different … Read more
REQUIREMENTS OF FORMWORK – QUALITY, SAFETY & ECONOMY In the selection of materials for formwork, the three general principles of quality, safety and economy must be paramount. Material quality can ensure safety, and significantly contributes to the achievement of economy. Formwork failure can result in loss of life and always causes catastrophic financial loss. Some … Read more
Properties of Mortar Properties of mortar which are sought for use in masonry are: workability, water retentivity, rate of stiffening, strength, resistance to rain penetration and durability. These properties have been discussed below explaining their effect on masonry. Choice of masonry mortar is governed by several considerations such as Type of masonry unit and its … Read more
TYPES OF LOADS External loads on a structure may be classified in several different ways. In one classification, they may be considered as static or dynamic. Static loads are forces that are applied slowly and then remain nearly constant. One example is the weight, or dead load, of a floor or roof system. Dynamic loads … Read more
Why Beam-Column Joints are Special In RC buildings, portions of columns that are common to beams at their intersections are called beam-column joints (Figure 1). Since their constituent materials have limited strengths, the joints have limited force carrying capacity. When forces larger than these are applied during earthquakes, joints are severely damaged. Repairing damaged joints … Read more
PLASTERING Applying mortar coats on the surfaces of walls, columns, ceiling etc. to get smooth finish is termed as plastering. Mortar used for plastering may be lime mortar, cement mortar or lime-cement mortar. Lime mortar used shall have fat lime to sand ratio of 1 : 3 or 1 : 4. If hydraulic lime is … Read more
THE COMMON TYPES OF PLASTIC Different types of plastics that are used in construction industry are described below. 1. Polyethylene Plastic (PE) Polyethylene plastic is made from the polymerized vinyl monomers. Monomer is a kind of simple compound, which can be polymerized to become macromolecular compound. Three ways are used to polymerize the monomer: high-pressure … Read more