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Showing papers on "Mortar published in 1968"


Journal ArticleDOI
01 Apr 1968
TL;DR: In this paper, the authors investigated the effect of different conditions on the likelihood of Morton cracks, such as air temperature, humidity, wind velocity, and wind velocities, and found that the first crack was associated with the transition from the Intensive, PRACTICALLY UNRESTRAINED, LINEAR SHRINKAGE of FRESH MORTAR to the much slower RATE.
Abstract: PLASTIC SHRINKAGE CRACKING OF MORTARS EXPOSED TO DIFFERENT CONDITIONS, AS PREVALENT IN HOT-DRY CLIMATES, WAS INVESTIGATED UNDER CONTROLLED CONDITIONS. THE VARIABLES STUDIED WERE AIR TEMPERATURE AND HUMIDITY, WIND VELOCITY, MORTAR TEMPERATURE, TYPE AND CONTENT OF CEMENT, AND CONSISTENCY. SHRINKAGE, TENSILE STRENGTH AND TENSILE STRESS OF FRESH MORTARS, EVAPORATION AND TIME OF CRACKING WERE MEASURED. WIDTH, DEPTH, AND LENGTH MEASUREMENTS OF THE CRACKS WERE ALSO TAKEN. THE RESULTS CONFIRM THAT RAPID EVAPORATION HAS A PREDOMINANT EFFECT ON PLASTIC SHRINKAGE CRACKING. OTHER CONCLUSIONS ARE THAT PLASTIC SHRINKAGE CRACKING IS NOT A DIRECT FUNCTION OF WATER LOSS, EVAPORATION RATE OR SHRINKAGE, AND THAT SEMIPLASTIC MORTAR DID NOT CRACK UNDER HIGH EVAPORATION CONDITIONS WHICH BROUGHT ABOUT SEVERE CRACKING OF PLASTIC AND WET MORTARS. IT WAS ALSO ESTABLISHED THAT THE FIRST CRACK COINCIDES WITH THE TRANSITION FROM THE INTENSIVE, PRACTICALLY UNRESTRAINED, LINEAR SHRINKAGE OF FRESH MORTAR TO THE MUCH SLOWER RATE DUE TO RESTRAINT ON STIFFENING OF THE MORTAR. /ACI/

67 citations


01 Jan 1968
TL;DR: In this article, the authors investigated the effect of the presence of interfaceted and inter-correlations between the two types of crack and found that BOND is much weaker than MORTAR and PASTE.
Abstract: INTERNAL CRACKING OF CONCRETE IS OBSERVED DIRECTLY WITH A MICROSCOPE AND WITH A NEWLY DEVELOPED X-RAY TECHNIQUE. CRACKS ARE OBSERVED BOTH AT THE INTERFACE BETWEEN COARSE AGGREGATE AND MORTAR, AND DIRECTLY THROUGH THE MORTAR. TO INVESTIGATE THE SIGNIFICANE OF THESE TWO TYPES OF CRACK, AND OF THE PRESENCE OF INTERFACIAL CRACKS BEFORE ANY LOADING, TENSILE AND SHEAR BOND STRENGTHS OF THE MORTAR-AGGREGATE INTERFACES ARE MEASURED AND COMPARED WITH STRENGTHS FOR MORTAR AND PASTE ALONE. THEORETICAL MODELS RELATING BOND STRENGTHS TO MICROCRACKING WERE DEVELOPED AND TESTED BRIEFLY. STRESSES FROM VOLUME CHANGES ON SETTING AND HARDENING ARE CONSIDERED. BOND BETWEEN PASTE OR MORTAR AND AGGREGATE IS FOUND TO BE MUCH WEAKER THAN ANY OF THE CONSTITUENTS ALONE. CONCRETE SPECIMENS ARE UNIAXIALLY LOADED, BOTH CONCENTRICALLY AND ECCENTRICALLY, IN COMPRESSION TO VARIOUS STRAINS UP TO FAILURE. INTERNAL MICROCRACKING, DISTINGUISHED AS TO BOND OR MORTAR CRACKING, IS RELATED TO AMOUNT OF STRAIN, AND A PHYSICAL, SEMI-QUANTITATIVE PICTURE OF THE PROGRESS OF CRACKING UP TO FAILURE IS DEVELOPED. THE STRAIN GRADIENT IN ECCENTRICALLY LOADED SPECIMENS SEEMS TO RETARD NOTICEABLY THE AMOUNT OF CRACKING TRHOUGH MORTAR. PROGRESSIVE DEVELOPMENT OF MICROCRACKING IS APPARENTLY DIRECTLY RELATED TO THE SHAPE OF THE STRESS-STRAIN CURVE IN SHORT-TERM COMPRESSION. THE HETEROGENEITY INDUCED BY AGGREGATES SEEMS TO BE RESPONSIBLE FOR BOND CRACKING AND THEREFORE FOR MOST OF THE SHORT-TERM INELASTIC BEHAVIOR OF CONCRETE. /A/RRL/

34 citations



DOI
01 Jan 1968
TL;DR: In this article, it is shown that the authors of this paper confirm the HYPOTHESIS of HIGHER BIAXIAL and TRIAXial RATHER THAN UNIAXIXIAL CONCRETE COMPRESSION STRENGTH.
Abstract: ELEMENTS OF A UNIFIED THEORY OF THE MECHANICAL BEHAVIOR OF CONCRETE ARE DEVELOPED FROM NO-LOAD TO FRACTURE UNDER SHORT-TIME LOADING BASED ON OBSERVED MICROCRACK BEHAVIOR AND ON A STATISTICAL DISTRIBUTION OF MORTAR STRENGTH. IT IS KNOWN THAT IN UNIAXIAL COMPRESSION, AGGREGATE AND HARDENED CEMENT PASTE, THE TWO CONCRETE CONSTITUENTS, ARE ALMOST WHOLLY ELASTIC TO FRACTURE. FOR MORTAR THE STRESS-STRAIN CURVE IS MORE PRONOUNCED AND THE STRENGTH IS LESS THAN FOR PASTE OF THE SAME WATER-CEMENT RATIO. CONCRETE IN TURN HAS A STRESS-STRAIN CURVE WHICH IS STILL MORE CURVED AND THE STRENGTH BECOMES LESS THAN FOR MORTAR OF THE SAME WATER-CEMENT RATIO. FROM THIS IT IS SHOWN THAT CONCRETE'S INELASTICITY AND STRENGTH ARE GOVERNED BY PASTE-AGGREGATE INTERACTION, CONDITIONED BY THE FACT THAT IN AGREEMENT WITH PREVIOUS FINDINGS, THE AGGREGATE-MORTAR INTERFACE CONSTITUTES THE WEAK LINK. BASED ON THESE STATISTICAL FINDINGS REGARDING THE ELASTICITY OF AGGREGATE AND HARDENED CONCRETE PASTE, IT IS DEMONSTRATED THAT A PROGRESSIVELY INELASTIC CONDITION DEVELOPS IN CONCRETE UNDER SHORT-TIME LOADING AND CONTINUES UP TO THE CRITICAL LOAD OF 85 TO 90 PERCENT OF ULTIMATE INELASTICITY. IT IS DESCRIBED THAT THIS INELASTICITY RESULTS CHIEFLY FROM BOND CRACKING AT THE AGGREGATE-MORTAR INTERFACE. IT IS SHOWN THAT IN THIS RANGE A REALISTIC STRESS-STRAIN CURVE CAN BE CALCULATED ENTIRELY ON THE BASIS OF SEPARATELY OBSERVED MICROCRACK BEHAVIOR AND INDEPENDENTLY MEASURED MATERIALS CONSTANTS. IT IS CONCLUDED THAT THE CRITICAL LOAD IS THE POINT AT WHICH INCREASINGLY EXTENSIVE MORTAR CRACKING CAUSES VOLUME EXPANSION AND THE HITHERTO ESSENTIALLY CONTINUOUS MATERIAL CHANGES TO AN ESSENTIALLY DISCONTINUOUS ONE. INCREASED INTERFACIAL FRICTION AND THE REDUCTION OF MORTAR TENSILE STRESSES, AS SHOWN STATISTICALLY IN THIS PAPER, CONFIRM THE HYPOTHESIS OF HIGHER BIAXIAL AND TRIAXIAL RATHER THAN UNIAXIAL CONCRETE COMPRESSION STRENGTH. IT IS FURTHER CONCLUDED THAT THE BEHAVIOR THEORY DEMONSTRATES THAT CONCRETE'S SHORT-TIME INELASTICITY CAN BE EXPLAINED ENTIRELY ON THE BASIS OF BRITTLE MICROBEHAVIOR WITHOUT INVOKING ANY EXPERIMENTALLY UNOBSERVED FLOW-PROCESSES. /ACIJP/

16 citations


01 Jan 1968
TL;DR: The use of STEEL FIBERS in PORTLAND CEMENT PRODUCTS will PROBABLY be limited to special applications where CONVENTIONAL REINFORCEMENT IS not SATISFACTORY as discussed by the authors.
Abstract: FIBERS OF PRINCIPAL CURRENT INTEREST FOR USE AS REINFORCEMENT IN PORTLAND CEMENT PRODUCTS INCLUDE ASBESTOS, GLASS, PLASTICS AND STEEL. CONSIDERABLE RESEARCH IS NOW DIRECTED TOWARD THE DEVELOPMENT OF MATERIALS AND MANUFACTURING METHODS THAT WOULD ALLOW THE SUBSTITUTION OF GLASS FIBERS FOR ASBESTOS FIBERS IN PORTLAND CEMENT PASTE AND MORTAR. PLASTIC FIBERS MAY SERVE A USEFUL PURPOSE AS ENERGY ABSORBERS IN CONCRETE THAT IS SUBJECT TO EXPLOSIVE LOADING. BECAUSE OF COST, THE USE OF STEEL FIBERS IN PORTLAND CEMENT PRODUCTS WILL PROBABLY BE LIMITED TO SPECIAL APPLICATIONS WHERE CONVENTIONAL REINFORCEMENT IS NOT SATISFACTORY. /AUTHOR/

16 citations


Journal ArticleDOI
01 Feb 1968
TL;DR: In this paper, the authors conducted an exploratory investigation to compare the COMPRESSIVE STRENGTH of CONCRETE MADE with GLASS MARBLES as the coarseness of a grander grander with the robustness of a simpler grander.
Abstract: THIS REPORT SUMMARIZES A LONGER REPORT DESCRIBING AN EXPERIMENTAL INVESTIGATION WHICH COMPARED COMPRESSIVE STRENGTH OF CONCRETE MADE WITH GLASS MARBLES AS THE COARSE AGRREGATE WITH THE COMPRESSIVE STRENGTH OF CONCRETE IN WHICH THE BOND BETWEEN MORTAR AND GLASS MARBLES WAS RAISED BY COATING THE MARBLES WITH A THIN LAYER OF SOFT PLASTIC. IT IS CONCLUDED THAT COATING REDUCES THE COMPRESSIVE STRENGTH UP TO 2.5 TIMES, THE STRENGTH REDUCTION BEING ALMOST PROPORTIONAL TO THE VOLUMETRIC CONTENT OF GLASS MARBLES IN THE CONCRETE. /AUTHOR/

12 citations


Patent
27 Jun 1968
TL;DR: A wheeled vehicle for storing and dispensing pulverized or granular material such as fertilizer, grain, etc., and more particularly cement, especially mortar cement, at a place where the material is to be used, such as, a residence or a construction site and the like, and which dispenses the material in portions of predetermined size or amounts as discussed by the authors.
Abstract: A wheeled vehicle for storing and dispensing pulverized or granular material such as fertilizer, grain, etc., and more particularly cement, especially mortar cement, at a place where the material is to be used, such as, a residence or a construction site and the like, and which dispenses the material in portions of predetermined size or amounts.

11 citations


Patent
26 Dec 1968
TL;DR: In this paper, an approach for truing a cement mortar coating on a concrete pipe body or the like including means for supporting and rotating the body and a power-driven rotary brush mounted to be moved longitudinally of the body.
Abstract: Apparatus for truing a cement mortar coating on a concrete pipe body or the like including means for supporting and rotating the body and a power-driven rotary brush mounted to be moved longitudinally of the body.

9 citations



Patent
09 Aug 1968

7 citations


Journal ArticleDOI
01 Jan 1968
TL;DR: Aqueous polymer dispersions have been used to modify concrete and mortar properties as mentioned in this paper, and some research work has been made to find the optimum type and proportion of polymer dispersion admixture.
Abstract: Aqueous polymer dispersions admixed to cement concretes or mortars affect their properties. Some research work has been made to find the optimum type and proportion of polymer dispersion admixture, and to see how concrete and mortar properties are thereby modified.

Journal ArticleDOI
TL;DR: In this article, the use of the ballistic mortar as a means of measuring performance parameters of ammonium nitrate (AN)/fuel explosives was examined and the significance of bubble energy in rock breakage processes was discussed.

Patent
13 Mar 1968
TL;DR: In this paper, a fine aggregate of size 3-25 mm was proposed for concrete concretes and mortars, with a maximum grain size of 3 to 7 mm and a grain size between 0.2 mm and 1 mm.
Abstract: 1,218,411 Mortar and concrete THERMOCRETE BAUPATENTE - VERWERTUNGSGES ETAB 13 March, 1968, No 12235/68 Heading C1H Portland cement or lime mortars and concretes contain as a fine aggregate a crushed vitreous slag having a maximum grain size of 3 to 7 mm and of which, by weight, 3-25% is below 0A06 mm, 9-40% is below 0A2 mm, 43-80% is below 1 mm, and 30-60% is between 0A2 mm and 1 mm Suitable fine aggregates are fused boiler slag, direct process slag, granulated blast-furnace slag, slag from the production of phosphorus, sintered garbage incineration slag and mixtures of these A coarse aggregate of size 3-25 mm can be included, eg foamed slag, natural pumice, chips of volcanic and porous rocks (lava), expanded clay, porous aggregate made from fly ash, expanded slate, sintered grit, sintered garbage incineration slag and mixtures of these Synthetic resin may be included in the binder

Patent
21 Jun 1968
TL;DR: In this paper, a machine for the spreading of the mortar on building materials such as concrete blocks, bricks, stonemasonry, and concrete blocks is described, where one hand is used to push the machine along a row of bricks with one hand and the other hand to push it to a block by the action of another hand.
Abstract: THIS INVENTION RELATES TO A MACHINE FOR THE SPREADING OF MORTAR ON MASONARY BUILDING MATERIAL SUCH AS CONCRETE BLOCKS, BRICK, STONE AND THE LIKE. SPECIFICALLY, THE MORTAR SPREADER MACHINE ENCOMPASSES ROLLERS ADAPTED TO BE ROLLED ON A FIRST ROW OF MASONARY MATERIAL. THE ROLLERS IN TURN ARE SECURED TO A HOPPER THAT INCLUDES A FORE AND AFT SPREADER AND MEANS FOR ADVANCING AND FEEDING THE MORTAR FROM THE HOPPER TO THE SPREADER. THE MACHINE IN OPERATION IS PUSHED (ROLLED) ALONG THE ROW OF MASONRY MATERIAL WITH ONE HAND AND THE MORTAR FED TO THE BLOCK BY THE ACTION OF THE OTHER HAND. AS THE MACHINE IS PUSHED, THE MORTAR IS EVENLY AND UNIFORMLY SPREAD ON THE MASONRY MATERIAL.



Journal ArticleDOI
01 Mar 1968
TL;DR: In this article, two Rotating Viscometers were used in the LABORATORY or on CONSTRUCTION SITES for CEMENT PASTE, MORTAR and CONCRETE.
Abstract: DETAILS ARE GIVEN OF TWO ROTATING VISCOMETERS WHICH CAN BE USED IN THE LABORATORY OR ON CONSTRUCTION SITES FOR CEMENT PASTE, MORTAR AND CONCRETE /LCPC/RRL/

Journal ArticleDOI
01 Oct 1968
TL;DR: In this article, the advance of the state of the art of cement mortar lining pipelines in-place is described by relating the history of the cement mortar linings and a description of the process is given as related to the material and equipment.
Abstract: The writer describes the advance of the state of the art of cement mortar lining pipelines in-place, which is done by relating the history of cement mortar lining. Also description of the process is given as it is related to the material and equipment. The advantages of lining pipelines with cement mortar in-place are enumerated, and the trend toward the lining of large diameter pipelines is examined. Numerous applications of in-place cement mortar lining during the past have been described and referenced.

Journal ArticleDOI
TL;DR: In this article, the authors describe a number of modifications of the mortar aimed at decreasing energy losses by gas leakage, heat conduction, and plastic deformation of the firing chamber, and the new values agree with theoretical predictions based on calculated values of explosion energy and gas volume.
Abstract: In the past, the ballistic mortar has been used extensively for comparative measurements of the explosion energy of different explosives. This paper describes a number of modifications of the mortar aimed at decreasing energy losses by gas leakage, heat conduction, and plastic deformation of the firing chamber. By these measures, the mortar energy has been increased by about 30% for the same quantity of explosive, and the new values agree with theoretical predictions based on calculated values of explosion energy and gas volume.


Journal ArticleDOI
01 Mar 1968
TL;DR: In this paper, the authors discuss water-reduction, change in consistency, and change in Consistency, and the effect of influences of different types of extracurricular activities.
Abstract: THE FOLLOWING ARE PRESENTED: (1) WATER-REDUCTION AND CHANGE IN CONSISTENCY, FUNDAMENTAL CONCEPTS; (2) INFLUENCE OF TYPE OF ADMIXTURES; (3) OTHER PROPERTIES OF WORKABILITY; (4) ENTRAINMENT OF AIR, FUNDAMENTAL CONCEPTS; (5) INFLUENCE OF TYPE OF ADMIXTURE; (6) INFLUENCE OF CONCRETE PROPORTIONS AND MATERIALS; (7) BLEEDING; (8) STIFFENING BEFORE SETTING; (9) SETTING; (10) INITIAL HARDENING; (11) HEAT EVOLUTION; (12) PLASTIC SHRINKAGE; (13) FREEZING AT EARLY AGES, AND (14) INFLUENCE OF CONCRETE PROPORTIONS AND MATERIALS. /RRL/




01 May 1968
TL;DR: In this article, Y.S. KUBOTA et al. performed a comprehensive study on the use of VINYL by-products in MORTAR, and found that the VINY-RESIN ADDITIONS improved the strength and deformation of MORTARS.
Abstract: CONTENTS: PRACTICE AND THEORY OF POLYMER CEMENT CONCRETE, Y.S. CHERKINSKY THE EFFECT OF POLYVINYL ACETATE EMULSION AND SYNTHETIC RUBBER LATEX ON THE STRENGTH AND DEFORMABILITY OF MORTARS, A.E. DESOV STUDY OF PHYSICAL AND MECHANICAL PROPERTIES OF CEMENT RESIN MORTAR, P. DUTRON, Y. COLLET USE OF LOW PERCENTAGE OF PVA AS AN ADMIXTURE TO CEMENT CONCRETE, R.K. GHOSH, C.S. PANT A STUDY OF THE IMPROVEMENT OF CEMENT MORTAR BY ADMIXING POLYMER EMULSION AND SYNTHETIC FIBER, H. KUBOTA, K. SAKANE CONCRETE, MORTAR AND SLURRY. IMPROVEMENT BY ADDITION OF RESINS, R. LEZY, A PAILLERE A COMPLEMENTARY STUDY ON THE USE OF VINYL BY-PRODUCTS IN MORTAR, P. MATTIOTTI COMPARISON OF PROPERTIES WITH VARIOUS POLYMER-MODIFIED MORTARS, Y. OHAMA CEMENT MORTARS MODIFIED BY SB LATEXES WITH VARIABLE BOUND STYRENE, Y. OHAMA THE INFLUENCE OF WATER SOLUBLE RESIN ADDITIONS ON THE PRINCIPAL QUALITIES OF MORTARS AND CONCRETES, A.V. SATALKIN, V.A. SOLNSEV, O.S. POPOV THE EFFECT OF BITUMEN EMULSION AND SYNTHETIC RESIN ADDITIVES ON THE BEHAVIOR OF CONCRETE IN MOIST CONDITIONS, W. SCHULTZE, H. LANGE POLYMER-MODIFIED MORTAR STRUCTURES AND THEIR DURABILITY, L. SKUPIN DISPERSON OF PLASTIC MATERIALS. CRITERION FOR THE SELECTION OF TYPE OF MATERIAL, P. STIBBANY ADVANTAGES TO BE DERIVED FROM THE PROPERTIES OF EPOXY RESIN USED AS CONCRETE ADMIXTURE, O. VALENTA, B. KUCERA EXPERIMENTAL INVESTIGATIONS CONCERNING THE USE OF SYNTHETIC RESINS IN THE CONCRETE TECHNIQUE OF ROMANIA, PART I N. VOINA, M. ENCULESCU, E. SCHILLER. /LCPC/RRL/