Factors Affecting the Setting and Hardening of Portland cement (1) The Impact of Cement’s Composition The mineral composition of cement and their ratios are the main factors affecting the setting and hardening of cement. As mentioned above, various mineral components will reveal different characteristics when reacting with water. For example, the increase of C3A can … Read more
Quality Requirements of Pumped Concrete Pumped concrete can be used for most structural concrete construction but is most useful where space for construction equipment is limited or access is difficult. Concrete pumps can be either truck- or trailer mounted and range from small units, exerting pressures from 250 to 300 psi and outputs of 15 … Read more
Selection of Concrete Mix Proportions Concrete mix proportions is a process of optimization of several desirable characteristics based on the project requirements. The characteristics to be optimized are economy, strength, durability, and placeability. 1. Economy The primary reason for systematically determining mixture proportions is economy. The maximum economy can be achieved by minimizing the amount … Read more
What is Corrosion of Steel? The term corrosion is defined as an act or process of gradual wearing away of a metal due to chemical or electro-chemical reaction by its surroundings such that the metal is converted into an oxide, salt or some other compound. A substance known as rust results from such a process. … Read more
Properties of Concrete in Plastic State 1. Essential Qualities The quality of the hardened concrete is largely dependent on the quality of the plastic concrete. The curing process also contributes to attainment of the specified design criteria. Because the consistency of the mix may vary, careful adherence to design criteria is extremely important. When the … Read more
What is Compaction of Concrete? Compaction of concrete is one of the important site operations that together enable the fresh concrete to reach its potential design strength, density and low permeability. Properly carried out it ensures that concrete fully surrounds and protects the reinforcement, tendons and cast-in inserts. It also has a direct impact on … Read more
Role of Steel in Concrete Reinforced concrete is a material that combines concrete and some form of reinforcement into a composite whole. Whilst steel bars, wires and mesh are by far the most widely used forms of reinforcement, other materials are used in special applications, e.g. carbon-filament reinforcement and steel fibres. Concrete has a high … Read more
Fly Ash Fly ash or pulverized fuel ash (PFA) is the residue from the combustion of pulverized coal collected by mechanical or electrostatic separators from the flue gases or power plants. It constitutes about 75 per cent of the total ash produced. The properties and composition of fly ash vary widely, not only between different … Read more
How to Cure Concrete in Cold Weather? Curing concrete becomes a more challenging job in colder days. Heavy snowfall and excessive humidity in the air are a few typical sights of the winter season which prevent concrete slabs from hardening properly in time. When temperature goes below 0 degree Celsius or minus 7 degree Celsius, … Read more
Corrosion of Concrete Reinforcement Corrosion is a chemical process of destruction of material because of its reaction with the environmental conditions. The most predominant among various factors of corrosion is the atmospheric corrosion which causes the rusting of steel. Appreciable corrosion only starts when the relative humidity of the air exceeds around 65%. In dry, … Read more