Cements hydraulic

Hydrauhc cements are used to coat pipe inside and outside, especially pipes that are to be buried or submerged, for example, water or sewer lines. In the case of underwater piping to transport gas or hquid hydrocarbons, for example, it may be mixed with barites or other heavy materials to confer negative buoyancy. It also may be used in mixtures of organic materials where its ability to maintain a noncorrosive pH at the surface of steel is exploited. 

Cast iron, ductile iron, or steel pipe may be coated at the mill by a process during which the pipe is spun on the center of its longitudinal axis while a mortar mixture is sprayed onto the inside surface in a uniform, dense layer. After proper curing, provided the pipe is handled carefully, this coating can protect the pipe interior against attack by water and many other liquid and gaseous corrosive environments. 

A concrete coating on steel of any configuration can be protective to the steel as long as it does not crack or spall off, as in Fig. 14.10 because the alkaline reaction of hydraulic cement maintains a high pH at the steel surface, which effectively prevents corrosion. It does this when encasing reinforcing steel, for example, where it functions both as strength and protective component. 

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Portland cement A hydraulic cement made from CaC03 and aluminium silicates. 

Cementgrout Cement, hydraulic Cementing agents Cementite... 

Cast and Hand-Molded Refractories. Large shapes such as burner blocks and flux blocks, and intricate shapes such as glass feeder parts saggers are produced by casting sHps, hydraulic cement bonded mixtures, or hand-molding clay or chemically bonded materials. Because these techniques are labor intensive, they are reserved for articles that caimot be satisfactorily formed in any other way, owing to complexity or small production quantities. 

Blended hydraulic cements are used to conserve energy. They are intimate and uniform blends of tine materials such as Pordand cement, ground blast furnace slag, dy ash, and other po22olans, ie, tine, reactive sUica sources. ASTM C595 Hsts five classes or types. 

The use of ozone has been proposed in special ore-flotation processes. Two widely different applications involve hydraulic cement and the fabrication of coating on insulators. 

Shiflett, Particle Size Investigation of Polyox WSR 301 Polymer Powders Using a Turbidity Technique", NSRDC 28-621 (1973) 45) Anon, Standard Method of Test for Fineness of Hydraulic Cement by the No 325 (45 p m) Sieve", ASTM C430-75 (1975) 46) D.J. 

Hydraulic cements. These cements are formed from two constituents one of which is water. Setting comprises a hydration and precipitation process. Into this category fall Portland cement and plaster of Paris. 

The mechanism by which sulphur has these observed effects is as follows. Immersion of native magnesium oxychloride cement in water brings about a slow dissolution which creates pores. When those pores are filled with sulphur, sites of possible stress concentration at points of contact between particles are modified. Similar effects occur when sulphur is used to impregnate hydraulic cements based on Portland cement and silica (Beaudoin, Ramachandran Feldman, 1977). 

Gillmore, Q. A. (1864). Practical Treatise on Limes, Hydraulic Cements and Mortars. New York. 

In hydraulic cement slurries, fluid loss additives based on sulfonated or sulfomethylated lignins have been described. 

Homopolymers and copolymers from amido-sulfonic acid or salt containing monomers can be prepared by reactive extrusion, preferably in a twin screw extruder [1660]. The process produces a solid polymer. Copolymers of acrylamide, N-vinyl-2-pyrrolidone, and sodium-2-acrylamido-2-methyl-propane sulfonate have been proposed to be active as fluid loss agents. Another component of the formulations is the sodium salt of naphthalene formaldehyde sulfonate [207]. The fluid loss additive is mixed with hydraulic cements in suitable amounts. 

Similar copolymers with N-vinyl-N-methylacetamide as a comonomer have been proposed for hydraulic cement compositions [669]. The polymers consist of AMPS in an amount of 5% to 95%, vinylacrylamide in an amount of 5% to 95%, and acrylamide in an amount of 0% to 80%, all by weight. The polymers are effective at well bottom-hole temperatures ranging from 200° to 500° F and are not adversely affected by brine. Terpolymers of 30 to 90 mole-percent AMPS, 5 to 60 mole-percent of styrene, and residual acrylic acid are also suitable for well cementing operations [253]. 

Addition of rubber particles of 30% to 100% by weight to cement with a grain size of approximately 40 to 60 mesh (0.4 to 0.25 mm) will produce a lightweight cement. The addition of rubber particles also creates a low permeability. The compositions are advantageous for cementing zones subjected to extreme dynamic stresses such as perforation zones and the junctions of branches in a multi-sidetrack well. Recycled, expanded polystyrene lowers the density of a hydraulic cement formulation and is an environmentally friendly solution for downcycling waste materials. 

Foam cement is a special class of lightweight cement. The gas content of foamed cement can be up to 75% by volume. The stability of the foam is achieved by the addition of surfactants, as shown in Table 10-9. A typical foamed cement composition is made from a hydraulic cement, an aqueous rubber latex in an amount up to 45% by weight of the hydraulic cement, a latex stabilizer, a defoaming agent, a gas, a foaming agent, and a foam stabilizer [359,362]. Foamed high-temperature applications are based on calcium phosphate cement [257]. 

ASTM C184-94E1 Standard test method for fineness of hydraulic cement by the 150-pm (No. 100) and 75-pm (No. 200) sieves. ASTM Book of Standards Volume 04.01, 2001. 

E. M. Gartner and R. P. Kreh. Cement additives and hydraulic cement mixes containing them. Patent CA 2071080, 1993. 

Source From AASHTO, AASHTO Designation M240 Blended hydraulic cements, in Standard. Specification for Materials, American Association of State Highway and Transportation Officials, 1986. 

Length change of hardened hydraulic-cement mortar and... 

Concretes are cements containing a large proportion of gravel. Hydraulic cements are cements that set (harden) in wet environments, as required when building structures submerged in water. Like all other cements used in ancient times, hydraulic cements were also composite materials in which one particular component, such as pozzolana in ancient Rome (see text below), endowed the cement with the property of setting in wet environments (Gani 1997 Akroyd 1962). 

Hydraulic Cements. To build constructions submerged in a sea, lake, or river, it is necessary to use waterproof cements, generally known as hydraulic cements, which harden even in the presence of excessive amounts of water. In the past, such cements were prepared by heating a mixture of limestone and a considerable amount of clay or other powdered siliceous material. At high temperature (above 650°C), the quicklime, formed when the limestone... 

Hydration antifouling coatings, 7 158 Hydraulic atomizers, 23 175 Hydraulic cements, 5 467, 500-501 Hydraulic-centrifugal classifiers, 22 275 Hydraulic classifiers, 76 619 Hydraulic conductivity, of landfill liners, 25 878... 

Reference ASTM 114—00, Standard Test Method for Chemical Analysis of Hydraulic Cement. As suggested in this document, the sample should not be a slag cement sample. Your instructor may choose to dispense... 

Portland cement refers to a class of hydraulic cements in which the two essential constituents are tricalcium silicate (3Ca0-Si02) and dicalcium silicate (2Ca0-Si02) with varying amounts of alumina, tricalcium aluminate, and... 

Before 1800 Cotton, flax, wool, and silk fibers bitumens caulking materials glass and hydraulic cements leather and cellulose sheet (paper) natural rubber Hevea brasiliensis), gutta percha, balata, and shellac 1839 Vulcanization of rubber (Charles Goodyear)... 

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