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When it reacts with concrete, it causes the slab to expand, lifting, distorting and cracking as well as exerting a pressure onto the surrounding walls which can cause movements significantly weakening the structure. Some infill materials frequently encountered in building fondations and causing sulfate attack are the following: [2] Red Ash
To attempt to simplify and to stylize a very complex set of various reactions, the whole ASR reaction, after its complete evolution (ageing process) in the presence of sufficient Ca 2+ cations available in solution, could be compared to the pozzolanic reaction which would be catalysed by the undesirable presence of excessive concentrations of alkali hydroxides (NaOH and KOH) in the concrete.
High-pressure chemistry is concerned with those chemical processes that are carried out under high pressure – pressures in the thousands of bars (100 kPa) or higher.High-pressure processes are generally faster and have a higher conversion efficiency than processes at ambient pressure.
Portland cement clinker was first made (in 1825) in a modified form of the traditional static lime kiln. [2] [3] [4] The basic, egg-cup shaped lime kiln was provided with a conical or beehive shaped extension to increase draught and thus obtain the higher temperature needed to make cement clinker.
The main portion of the hot gas from the combustion chamber flows through the tube of the process gas cooler and is cooled down such that the sulfur formed in the reaction step condenses. The heat given off by the process gas and the condensation heat evolved are utilized to produce medium or low-pressure steam. The condensed sulfur is removed ...
Here's a step-by-step overview: Surface Preparation: Ensure the concrete surface is clean and free of debris, oil, surface coatings and other contaminants. Application: Apply Ashford Formula with a low-pressure, high-volume sprayer at 200 ft 2 /gal (5 m 2 /L), creating a flood coat. Agitate the surface with fine-bristled brooms to help penetration.
Robotic Hydrodemolition in Folkestone, UK. Hydrodemolition of concrete exposing the rebar.. Hydrodemolition (also known as hydro demolition, hydroblasting, hydro blasting, hydromilling, waterblasting, and waterjetting) is a concrete removal technique which utilizes high-pressure water, often containing an abrasive material, to remove deteriorated and sound concrete as well as asphalt and grout.
operate at high pressure (on the order of 20 MPa [48]); implement one or more catalysts [49] to accelerate the synthesis of ammonia; operate at a high temperature (between 500 °C and 600 °C) to obtain the best efficiency in the presence of the catalyst; since about 5% of the N 2 and H 2 molecules react with each passage in the chemical reactor: