Tremie Concreting – On Site Precautions During tremie concreting the following precautions are to be taken while doing the work: The concrete should be coherent, rich in cement (not less than 370 kg/m3) and of slump between 150 and 180 mm. When concreting is carried out under water, a temporary casing should be installed to … 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
Telltale Signs for Choosing Right Concrete Cutting Contractor for Your Construction Project Most construction projects witness the need for concrete cutting and drilling for various purposes. And thus, it is essential for every size of a contractor, or a construction business, to have a good understanding of concrete cutting and how it can benefit your … 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
Impurities in Sand Clay, silt, salts, mica and organic matter are a source of impurities in sand. All sands are generally found to contain some percentage of silt and clay. Mica is easily discernible from its shining surface. A certain percentage of impurities are inevitable in sand; a maximum of 6 % of silt and … 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
Concrete Placing As with the handling of concrete, certain fundamental considerations govern placing techniques. First and perhaps foremost is the need to avoid segregation of the concrete caused by improper techniques. Second is the need to ensure thorough compaction of the concrete. The manner in which concrete is placed can have a significant influence on … 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