5 FACTORS CAUSING DISINTEGRATION OF CONCRETE

DISINTEGRATION OF CONCRETE

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

HOW TO MINIMISE THE DEFECTS IN PLASTERING WORK?

plastering

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

4 PRIMARY CEMENT COMPOUNDS & THEIR ROLES

cement compounds

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

8 PRIMARY REQUIREMENTS OF FORMWORK

REQUIREMENTS OF FORMWORK

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

SPLITTING TENSILE STRENGTH TEST OF CONCRETE (IS-516)

Determine Splitting Tensile Strength of Cylindrical Concrete Specimens Objective: This method covers the determination of the splitting tensile strength of cylindrical concrete specimens Reference: IS: 516 – 1959, IS: 1199-1959, SP: 23-1982, IS: 10086-1982 Theory: Age at Test – Tests shall be made at recognized ages of the test specimens, the most usual being 7 … Read more

HOW BEAM COLUMN JOINTS RESISTS EARTHQUAKES?

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

HOW TO CHECK SUITABILITY OF WATER FOR CONCRETE MIXING?

How to check quality of drinking water

SUITABILITY OF WATER FOR CONCRETE MIXING OBJECTIVE To assess suitability of water for use in concrete mix. Equipment Measuring cylinder Cube moulds Trowel Tamping rod Vibrating table Testing machine Procedure Analyse water for its chemical compositions as per IS 3025-1964 and compare these with permissible limits given in IS: 456-2000. In case water does not … Read more

WHETHER OR NOT TO SELECT CONCRETE FOR CONSTRUCTION?

concrete mix proportions

FACTORS AFFECTING CHOICE OF CONCRETE FOR A STRUCTURE The choice of whether a structure should be built of concrete, steel, masonry, or timber depends on the availability of materials and on a number of value decisions. 1. Economy Frequently, the foremost consideration is the overall cost of the structure. This is, of course, a function … Read more

PPC or PORTLAND POZZOLANA CEMENT

PPC Portland Pozzolana Cement

Portland Pozzolana Cement 1. Pozzolana Pozzolana is a volcanic powder found in Italy near Vesuvius A pozzolanic material is essentially a siliceous or aluminous material which possess no cementitious properties. But it has the property when it combined with lime to produce a stable pozzolana compound it has definite cementitious properties. In the presence of … Read more

WHAT ARE THE PROPERTIES OF AIR ENTRAINED CONCRETE?

Air entrained concrete

AIR ENTRAINED CONCRETE A major advance in concrete technology in recent years is the introduction of tiny disconnected air bubbles into concrete called air entrainment. Air entrained concrete results from using either an air-entraining cement or an air-entraining admixture during mixing. Adding entrained air to concrete provides important benefits in both plastic and hardened concrete, … Read more