Showing papers on "Cement published in 1971"

Reinforced concrete construction

Abstract: A reinforced concrete construction formed of a plurality of alternate, integrally bonded layers of epoxy resin-containing concrete and fiber-reinforced epoxy resin. The epoxy resin-containing concrete is a hardened mixture of hydraulic cement, aggregate, water in an amount sufficient to harden the cement, and a minor proportion of epoxy resin. Optionally, short pieces of epoxy resin coated glass fiber can be dispersed within the epoxy resin-containing concrete. The construction can be formed into a relatively thin-walled, laminated article of any desired size and configuration. Also disclosed is a method for fabricating the constructions of this invention.

Lightweight,high strength concrete and method for manufacturing the same

Abstract: A LIGHTWEIGHT, HIGH STRENGTH CONCRETE IS FORMED BY MIXING WITH WATER, AN ADMIXTURE OF FINE AGGREGATE CONSISTING SOLVELY OF COAL FLY ASH CENOSPHERES AND DRY HYDRAULIC CEMENT, THEN SOLIDIFYING THE MIXTURE.

Early curing behavior of cement modified asphalt emulsion mixtures

Abstract: THE EFFECT OF ADDING SMALL AMOUNTS OF PORTLAND CEMENT TO ACCELERATE AND CONTROL THE SETTING TIME OF ASPHALT EMULSION MIXTURES WAS INVESTIGATED. CRUSHED, DENSE-GRADED AGGREGATE MATERIAL WAS MIXED WITH QUICK-SETTING EMULSION, SLOW-SETTING EMULSION, AND VARYING AMOUNTS OF TYPE I PORTLAND CEMENT, RANGING FROM 0 TO 3 PERCENT. SPECIMENS CURED IN COOL, WET CONDITIONS WERE OF PARTICULAR INTEREST BECAUSE OF THE UNPREDICTABLE CURING BEHAVIOR OF ASPHALT EMULSIONS IN SUCH WEATHER. IT WAS FOUND THAT PORTLAND CEMENT INCREASED THE RATE OF CURING AT ALL PERCENTAGES UP TO THREE PERCENT. THE PRESENCE OF THE CEMENT, HOWEVER, INCREASED THE STIFFNESS DURING MIXING. THE ADDITION OF CEMENT LARGELY OVERCAME THE EFFECTS OF ADVERSE (COOL, WET) CURING CONDITIONS AND IT INCREASED THE ULTIMATE OR MAXIMUM RESILIENT MODULUS OF THE ASPHALT MIXTURE BY 200 PERCENT. THE QUICK-SETTING EMULSION WAS BENEFITTED BY THE TREATMENT MORE THAN THE SLOW-SET EMULSION.

Portland cement compositions and method

Abstract: A FREE-FLOWING EXPANDING CEMENT PASTE IS MADE BY MIXING FINELY GROUND CEMENT WITH AT LEAST 0.0025 PART OF ALKALI OR ALKALINE EARTH LIGNOSULFONATE AND WITH ABOUT 0.20-0.28 PART OF WATER CONTAINING AT LEAST 0.0025 PART OF ALKALI CARBONATE. MIXTURES OF AGGREGATE WITH SUCH LOW-POROSITY PASTES YIELD, ON CURING, MORTARS AND CONCRETES OF IMPROVED STRENGTH AND DIMENSIONAL STABILITY.

Structure of Zinc Phosphate Dental Cement

Abstract: The zinc phosphate cement structure consists of excess zinc oxide particles in a non-crystalline, amorphous phosphate matrix. Crystals of hopeite (Zn3(PO4) 2·4H2O) can grow from the cement surface if excess water is present. Extensive pores and surface layers of crystals, which are dependent on moisture conditions, affect the strength and adhesive properties of the cement.

Cement compositions containing glass fibres

Abstract: FIBRE REINFORCED CEMENTITIOUS PRODUCTS ARE DESCRIBED COMPRISING GLASS FIBROUS MATERIAL DISTRIBUTED THROUGHOUT A CEMENT MATRIX, IN WHICH THE GLASS IS ONE HAVING PER SO A DEGREE OF ALKALI RESISTANCE WUCH THAT WHEN TESTED IN THE FORM OF AN ABRADED FIBRE OF LENGTH 2 1/2 INCHES AND DIAMETER OF FROM 0.4 TO 1.0X10-3 INCHES SAID FIBRE HAS A TENSILE STRENGTH OF AT LEAST 100,000 P.S.I. AFTER TREATMENT WITH SATURATED AQUEOUS CA(OH)2 SOLUTION AT 100*C. FOR 4 HOURS FOLLOWED BY SUCCESSIVE WASHINGS AT AMBIENT TEMPERATURE WITH WATER, THEM WITH AQUEOUS HYDROCHLORIC ACID (1%) FOR 1 MINUTE, WATER, ACETONE, FOLLOWING BY DRY ING. SAID FIBRE EXPERIENCING NOT MORE THAN 10% REDUCTION IN DIAMETER DURING SAID TEST. THE REINFORCEMENT OF PORTLAND CEMENT STRUCTURES BY FIBRES OF DIAMETER 0.4 TO 1.0 X 10-3 AND LENGTHS OF UP TO 4 INCHES IS DESCRIBED. ALKALI RESISTANT GLASSES USEFUL FOR PRODUCTION OF THESE PRODUCTS COMPRISES THE CAO-MGO-AL2O3-SIO2 GLASSES IN CLUDING THOSE IN THE ANORTHITE FIELD, SILICA ZIRCONIA GLASSES AND SILICA STANNIC OXIDE GLASSES. THE PRODUCTS HAVE OUTSTANDING DURABILITY AND IMPACT RESISTANCE.

Some Properties of Polymer-Impregnated Cements and Concretes

Abstract: POLYMER-IMPREGNATED CEMENT AND POLYMER-IMPREGNATED CONCRETE WERE PREPARED BY VACUUM-FILLING CURED AND DRIED CEMENT AND CONCRETE WITH A LOW-VISCOSITY MONOMER AND POLYMERIZING THE MONOMER BY A THERMAL-CATALYTIC OR GAMMA- RADIATION METHOD. THE STRENGTH AND DURABILITY OF THE PRODUCTS ARE SIGNIFICANTLY BETTER THAN THOSE OF THE UNIMPREGNATED MATERIALS. SOME OBSERVATIONS INVOLVING MONOMER LOADING, POLYMERIZATION, AND POLYMER DISTRIBUTION ARE DISCUSSED. A SIMPLE MODEL IS PRESENTED WHICH DESCRIBES THE VARIATION IN STRENGTH OF CEMENT AND CONCRETE WITH POLYMER CONTENT; THE MODEL IS COMPARED WITH EXPERIMENTAL RESULTS. /AUTHOR/

Interactions Between Cement Minerals and Hydroxycarboxylic‐Acid Retarders: I, Apparent Adsorption of Salicylic Acid on Cement and Hydrated Cement Compounds

Abstract: A RADIOISOTOPE ASSAY METHOD WAS DEVELOPED TO MEASURE THE APPARENT ADSORPTION OF SALICYLIC ACID ON CEMENT AND HYDRATED CEMENT COMPOUNDS AT CONCENTRATIONS OF SALICYLIC ACID IN AQUEOUS SOLUTION UP TO 0.2 WT%, THUS INCLUDING THE RANGE OF CONCENTRATIONS USED FOR HYDROXYCARBOXYLIC-ACID RETARDERS IN CONCRETE. PREVIOUSLY PUBLISHED DATA WERE AVAILABLE ONLY FOR CONCENTRATIONS BELOW 0.01%. THE RESULTS CONFIRM THAT THERE IS ONLY LIMITED APPARENT ADSORPTION ON DICALCIUM AND TRICALCIUM SILICATES, WHEREAS APPARENT ADSORPTION ON PASTE- AND BOTTLE-HYDRATED PRODUCTS OF THESE COMPOUNDS IS SIGNIFICANT. APPARENT ADSORPTION ON TRICALCIUM ALUMINATE IS STRONG AND IS GREATER AT INTERMEDIATE CONCENTRATIONS THAN NEAR SATURATION. A SIMILAR PATTERN WAS OBSERVED FOR APPARENT ADSORPTION ON TETRACALCIUM ALUMINOFERRITE BUT THE AMOUNTS REMOVED FROM SOLUTION WERE MUCH LESS. EXPERIMENTS WITH HYDRATED TETRACALCIUM ALUMINATE, HYDRATED TRICALCIUM ALUMINATE, AND ETTRINGITE REVEALED THAT HYDRATED CALCIUM ALUMINATE AND ALUMINATE SULFATE COMPOUNDS ALSO REMOVE MAJOR AMOUNTS OF SALICYLIC ACID FROM SOLUTION. /AUTHOR/

Through Pore Size Distribution and Kinetics of the Carbonation Reaction of Portland Cement Mortars

Abstract: Through pores of hardened cement mortars were studied by gas transfer experiments. The permeabilities were the same for N2 and H2. The pore size distribution of through pores was examined by back diffusion; the method was simplified by combining H2 and N2 gases. The permeability calculated from these results agreed with the experimental values of N2 and H2. The neutralization rate of hardened cement was expressed as L2=kθ(t-ti). The rate of neutralization was determined by the gas diffusion of both CO2 and H2O.

Method for extrusion

Abstract: This is a method for extrusion of materials normally difficult to extrude, particularly cement mixtures, especially such mixtures as asbestos and cement and the like, in which the invention and method is characterized by a special mixing method of the ingredients and by particular inorganic additive for plasticity, in which water and cement are mixed before mixing with other ingredients and/or fumed silica is used in the mix.

Physical classification of carbonate cement in quartzose sandstones

Abstract: The proposed classification of carbonate cement precipitated in quartzose sandstones is based upon two major characteristics: (1) crystallization of carbonate in available intergranular pores without modification in the arrangement of the detrital grain framework, or in the shape of such grains; (2) crystallization of cement involving expansion of the intergranular space and consequent rearrangement in the packing of detrital grains; or, crystallization of cement involving replacement and mineral substitution of detrital grains. The simple cement fills pores only and serves as a lithifying agent to preserve the fabric of the uncemented sediment. Cementation which is accompanied by volume expansion modifies grain-supported fabrics, can cause rupture of porous grains such as glauconite, can crystallize as concretions around grains, or as large, single poikilitic crystals, can replace grains of silicate minerals, or modify an original framework of carbonate grains by recrystallization.

Aluminum sulfate and calcium sulfate additives for improving the quality of cement,mortar and concrete and method for 0he production of such improved products

Abstract: AN ADDITIVE FOR IMPROVING THE PROPERTIES OF BUILDING MATERIALS, SUCH AS CEMENT, CONCRETE AND MORTAR, ESECIALLY FOR INCREASING THE EARLY STRENGTH, THE ABILITY TO CARRY OUT CONCRETING AT LOW TEMPERATURES AND FOR VOLUME CONTROL, WITHOUT IMPAIRING THE OTHER QUALITATIVE PROPERTIES OF THE BUILDING MATERIAL, WHEREIN THE ADDITIVE, APART FROM EXTENDERS AND/OR OTHER ADDITIVE SUBSTANCES CONSISTS OF CALCINATED, ANHYDROUS OR WATER FREE ALUMINUM SULFATE, TECHNIQUES ARE ALSO DISCLOSED FOR PRODUCING THE NOVEL ADDITIVE AS WELL AS FOR PRODUCING SUCH BUILDING MATERIALS WITH IMPROVED PROPERTIES.

Long-time durability of concrete in seawater

Abstract: DURING THE PAST 25 TO 30 YEARS, MORE THAN 2500 CONCRETE TEST SPECIMENS WERE EXPOSED TO SEAWATER AT A TEST STATION NEAR TRONDHEIM HARBOR, NORWAY. RESULTS FROM SOME OF THE MORE IMPORTANT LONG-TIME SERIES ARE PRESENTED. THE EFFECTS OF 18 DIFFERENT KINDS OF CEMENT; ADDITION OF TRASS, PRECURING, CEMENT CONTENT, WATER-CEMENT RATIO, AND SEAWATER VERSUS FRESH WATER AS MIXING WATER HAVE BEEN EXAMINED. THE BEHAVIOR OF THE CONCRETE WAS STUDIED BY FOLLOWING THE CHANGES OF FLEXURAL AND COMPRESSIVE STRENGTHS. THE RESULTS ARE DISCUSSED AND INTERPRETED ON THE BASIS OF CHEMICAL ANALYSIS AND PETROGRAPHIC EXAMINATION. /ACIJP/

Method for processing of red mud

Abstract: The red mud by-product of aluminum manufacture is processed by first removing its alkali metal content by causticization of a slurry thereof with burnt lime in the presence of humic acid or derivative thereof. From the remaining solids iron can be recovered such as by reduction and smelting, where the humic acid-containing ingredient, a soft coal, can be utilized for its carbon content. From the remaining slag of the smelting either an aluminaceous refractory cement is prepared or the solids are converted into a spontaneously disintegrating dicalcium silicate from which the aluminum content can be recovered. In the latter case the last remaining solids can be used in the manufacture of portland cement.

Quick-setting portland cement

Abstract: A PORTLAND CEMENT COMPOSITION IS DESCRIBED WHICH IS CAPABLE OF SETTING IN A SHORT PERIOD OF TIME THE CEMENT COMPOSITION CONTAINS AN ADDITIVE COMPOSED OF AN ETHANOLAMINE AND AN ACETATE, ACETIC ACID OR ACETIC ANHYDRIDE IN AMOUNTS BY WEIGHT BETWEEN ABOUT 01% AND 04% THE CEMENT COMPOSITION INCLUDES SULFUR COMBINED AS SO3 IN CONTROLLED AMOUNTS BETWEEN ABOUT 1% AND 25% AND HAS A BLAINE FINENESS OF AT LEAST ABOUT 4,000 SQUARE CENTIMETERS PER GRAM CONCRETE FORMED FROM THIS CEMENT COMPOSITION WILL DEVELOPED A COMPRESSIVE STRENGTH OF AT LEAST ABOUT 125 PSI WITHIN ABOUT TWO HOURS IN MORTAR TESTS

Cement set retarding composition and method

Abstract: A HYDRAULIC CEMENT COMPOSITION COMPRISES (A) THE CLINKER CONTAINING 5-60% BY WEIGHT OF 11 CAO. 7AL2O3. CAX2 SP (X REPRESENTS HALOGEN ATOM), MORE THAN 5% BY WEIGHT OF 3CAO.SIO2 SOLID SOLUTION, AND FURTHER 2CAO.SIO2 SOLID SOLUTION AND 4CAO. AL2O3.FE2O3 (4CAO.AL2O3.FE2O3 REPRESENTS 2CAO.FE2O3.6CAO.2AL2O3.FE2O3 SYSTEM SOLID SOLUTION); (B) ANHYDRITE WITH OR WITHOUT HEMIHYDRATE AND (C) AT LEAST ONE OF SULFATES, NITRATES AND CHLORIDES OF POTASSIUM, SODIUM, MAGNESIUM, CALCIUM, ALUMINUM OR AMMONIUM (EXCEPTING CASO4.2H2O, CASO4 AND CASO4.1/2H2O), WHEREBY THE ANHYDRITE IS CONTAINED IN AN AMOUNT THAT AL203/SO3 WEIGHT RATIO OF AL2O3 IN THE CLINKER AND SO3 IN THE ANHYDRITE IS 0.7-1.8 AND HEMIHYDRATE GYPSUM IS CONTAINED LESS THAN 5% BY WEIGHT AS SO3.

Shrinkage cracking of soil-cement base: theoretical and model studies

Abstract: THE PHENOMENON OF SHRINKAGE-INDUCED CRACKING IN SOIL-CEMENT BASES IS EXPLORED. AN ATTEMPT WAS MADE TO DELINEATE THE PRIMARY CAUSE OF CRACKING, AND EXPRESSIONS FOR THE SHRINKAGE STRESSES WERE DERIVED IN ACCORDANCE WITH LINEAR VISCOELASTIC THEORY. THE RESULTS SHOW THAT TENSILE SHRINKAGE STRESSES ARE HIGHLY LOCALIZED ON THE EXPOSED SURFACE. THEY ATTAIN MAXIMUM VALUE DURING THE FIRST FEW DAYS OF DRYING AND THEN DECREASE RAPIDLY. FOR QUANTITATIVE EVALUATION OF SHRINKAGE CRACKING, HOWEVER, EXPERIMENTS WERE CONDUCTED ON MODELS WHOSE DESIGN IS BASED ON A DIMENSIONAL ANALYSIS OF THE LINEAR PROBLEM OF SHRINKAGE CRACKING. EXPERIMENTAL RESULTS INDICATE THAT THE CRACK INTENSITY (DEFINED AS AREA OF CRACKS PER UNIT AREA) DECREASES WITH (1) AN INCREASE IN THE THICKNESS OF THE SLAB AND (2) A DECREASE IN THE VISCOSITY OF THE MATERIAL. ADEQUATE EXTENDED CURING IS EXTREMELY EFFECTIVE IN CONTROLLING CRACKING IN CEMENT BASE. IN THE 2 COARSE-GRAINED AND 1 FINE-GRAINED SOILS STUDIED, THE CRACK INTENSITY DECREASED WHEN THE CEMENT CONTENT EXCEEDED THE ASTM-PCA FREEZE-THAW CRITERION. ALSO, CRACK INTENSITY TENDED TO DECREASE WITH AN INCREASE IN SUBGRADE FRICTION. IN A SOIL-CEMENT MATRIX, RELATIVELY LARGE PIECES OF GRAVEL (NORMAL SIZE 1/2 TO 1 1/4 IN.) ENHANCED CRACKING. THE MODEL WAS USED IN A SEARCH FOR TREATMENTS THAT LED TO SEVERAL PROMISING ADDITIVES: LIME AND LIME WITH A TRACE AMOUNT OF SUGAR PROVED TO BE BEST IN A VARIETY OF SOILS; EXPANSIVE CEMENT ADMIXTURE AND SODIUM SILICATE SURFACE TREATMENT ARE EFFECTIVE IN COARSE-GRAINED SOILS. /AUTHOR/

High impact resistant double-walled container

Abstract: Plastic double-walled containers having a high impact-resistance wherein the space between the outer and inner walls is filled with a hardened gypsum cement and resin combination.

Additive cement compositions and method

Abstract: An additive composition for enhancing the properties of hydraulic cement compositions, and a hydraulic cement composition of enhanced properties, particularly useful in the cementing of wells, and methods of cementing geologic formations traversed by well bores are disclosed. The additive composition comprises a water soluble lignosulfonate or lignosulfonic acid or mixtures thereof, and tartaric acid or a salt of tartaric acid or mixtures thereof, and preferably about 3 parts calcium lignosulfonate and 1 part tartaric acid, although good results are obtained with 1 to 19 parts lignosulfonate or lignosulfonic acid and 19 to 1 parts tartaric acid or a salt of tartaric acid. The hydraulic composition includes a hydraulic cement and preferably about 11/2 % of the additive composition based on the weight of the cement; although , good results are obtained with from about 0.10% to about 3%, or higher, for example, for long life slurries. Especially good results are obtained when the hydraulic cement has been pretreated and aged as in our co-pending application filed Jan. 25, 1971, Ser. No. 109,606. The hydraulic cement composition has good viscosity and strength, ideal thickening times, and a reduced amount of mix water may be used thereby increasing the weight of the cement slurry. The method of performing cementing operations in geologic formations comprises introducing a slurry of the hydraulic cement composition in a well, positioning the cement slurry at cementing depth for bonding and plugging purposes, and allowing the cement slurry to harden. A number of examples are set forth disclosing the additive and hydraulic cement compositions, methods of making and using them.

Method for producing polymer impregnated foamed masonry elements

Abstract: A two-phase material of foamed cement or concrete and polymer providing thermal insulating, structural elements composed of an unimpregnated foam cement or concrete core and impregnated surface regions of the two-phase material and method employing a hydraulic head or vacuum means to provide high polymer loading through a large volume of foam voids in the cement or concrete for easy impregnation of high viscosity monomers and uncured resins to a considerable depth below the surface of the cement or concrete before in situ polymerization.

Light-weight high-strength cement compositions using hydrolyzed organic material

Abstract: A hydraulic cement binder consisting of magnesium oxide, magnesium sulfate and calcium chloride in proportion such that a magnesium oxychloride/magnesium oxysulfate/calcium sulfate hardenable mass is produced upon addition of water and setting. The binder is combined with cellulosic waste (municipality trash) which is treated with HCl or H2SO4 to partially hydrolyze the cellulosic material and thereafter with magnesium oxide or carbonate to neutralize it. For decreased brittleness and increased waterproofing characteristics, the binder contains sodium silicate and silicofluoride.

Solubility of cement as related to time of exposure in water

Abstract: The solubility of zinc phosphate, hydrophosphate, silicophosphate, and red copper cements was investigated as related to the time elapsed from the start of the mix until the specimen was exposed to water. The solubility of all four types of cement was appreciably greater when specimens were exposed to water 10 minutes from the start of the mix as compared to that which occurred when exposure to water was delayed for longer periods of time. The longer the time lapse between preparation of the specimens and immersion in water, the lower was the solubility of the cement. Thus, immediately following placement of cement in the mouth, all exposed surfaces should be protected from early contact with oral fluids by coating them with a water-impervious agent, such as a cavity varnish.

Influence of processing procedures on strength of sand stabilized with cationic bitumen emulsion

Abstract: THIS FIRST OF TWO PAPERS THAT DESCRIBE A LABORATORY STUDY OF THE FACTORS AFFECTING THE SHEAR STRENGTH OF A UNIFORMLY GRADED SAND STABILIZED WITH CATIONIC BITUMEN EMULSION IS CONCERNED WITH THE EFFECT OF MIXING PROPORTIONS, MIXING PROCESS, COMPACTION, AND CURING ON THE STRENGTH OF SAND-CATIONIC EMULSION MIXES. TRIAXIAL TESTS HAVE BEEN USED TO ASCERTAIN THE EFFECTS OF EMULSION CONTENT ON THE COHESION AND ANGLE OF SHEARING RESISTANCE OF STABILIZED SAND. UNCONFINED COMPRESSION TESTS WERE USED TO INVESTIGATE THE INFLUENCE OF THE VISCOSITY OF THE BASE BITUMEN AND ALSO THE EFFECT OF VARYING THE INITIAL MOISTURE CONTENT OF THE SAND. THE ADDITION OF FILLERS OF VARIOUS TYPES SUCH AS CEMENT, HYDRATED LIME, CRUSHED LIMESTONE, AND THE SAND HAS BEEN EXPERIMENTED WITH, AND THEIR INFLUENCE ON SHEAR STRENGTH HAS BEEN DETERMINED. A STUDY OF THE EFFECT (ON STRENGTH) OF CHANGING THE ORDER OF ADDITION OF INGREDIENTS DURING MIXING IS DESCRIBED. THE EFFECT OF AGING ON THE UNCONFINED COMPRESSIVE STRENGTH OF STABILIZED SAND IS REPORTED. /AUTHOR/