Showing papers on "Mortar published in 1982"
TL;DR: In this paper, the variation with time of the corrosion rates of galvanized steel and bare steel rebars has been studied as a function of the relative ambient humidity, mortar carbonation and the presence or absence of chloride ions.
Abstract: The variation with time of the corrosion rates of galvanized steel and bare steel rebars has been studied as a function of the relative ambient humidity, mortar carbonation and the presence or absence of chloride ions. Corrosion rates are estimated from Rp measurements with electronic compensation for the ohmic drop between the working imd reference electrodes.It is shown that a normal galvanized coating with a continuous layer of practically pure zinc in contact with mortar gives effective protection to the steel reinforcing bars against the aggressive action of carbonation and chlorides. The protective effect of this galvanized coating is much greater under partial immersion conditions of the mortar than in very humid atmospheres, although in the latter case the corrosion rate decreases with time.
130 citations
TL;DR: In this paper, the resistance to crack growth in mortar, concrete and fiber reinforced concrete was studied by testing double torsion and double cantilever speciments, and R-curves (plots of strain energy release rate vs. crack extension) were obtained from the test data.
Abstract: The resistance to crack growth in mortar, concrete and fiber reinforced concrete was studied by testing double torsion and double cantilever speciments. R-curves (plots of strain energy release rate vs. crack extension) were obtained from the test data. To include the inelastic strain energy absorbed during the crack extension, the definition of the strain energy release rate was modified. It was found that R-curves for mortar and concrete were similar for both double torsion and double cantilever speciments. R-curves were sensitive to the volume and size of aggregates and to the presence of fibers. It appears that R-curves can be a useful specimen-geometry-independent parameter for chracterizing the fracture behavior of cementitious composites. However, the effects of differing crack-opening displacement on the strain energy release rate must be considered; especially for fiber reinforced concrete.
62 citations
TL;DR: In this paper, a plausible energy balance equation is postulated and the Green-Rivlin invariance principle is applied to it to derive the linear and angular momentum balance laws.
61 citations
TL;DR: In this article, the Split-Hopkinson-Bar technique was used in the investigation on tensile stress-strain behaviour of concrete and mortar at high stress rates (5-30 N/mm 2 ms).
61 citations
Patent•
29 Sep 1982
TL;DR: Improved slag-powder cements as discussed by the authors are a mixture of ground calcium carbonate or an oven-dried Portland cement powder, or both, with ground granulated blast furnace slag.
Abstract: Improved cements used in the manufacture of concrete and mortar comprising a mixture of ground calcium carbonate or an oven-dried Portland cement powder, or both, with ground granulated blast furnace slag. While these physical and chemical characteristics are different from those of Portland cement, this cement is a functional substitute for Portland cement and can be used in combination with Portland cement in a wide range of proportions. The setting and other characteristics of this slag-powder cement can be improved by the addition of SO3, in general by adding ground gypsum and by the use of accelerators and formaldehyde-reducing compounds.
57 citations
01 Mar 1982
TL;DR: In this paper, a load-induced cracking of a small compact tension specimen of mortar was observed using a special loading device mounted in the specimen chamber of a scanning electron microscope, where the crack was initiated at a load of 43.6 N and immediately extended about 12 mm.
Abstract: The load-induced cracking of a small compact tension specimen of mortar was observed using a special loading device mounted in the specimen chamber of a scanning electron microscope. The crack was initiated at a load of 43.6 N and immediately extended about 12 mm, whereupon it became stable. Micromorphological aspects of the crack pattern are described in considerable detail. In general, it was observed that the crack geometry is complicated, with the crack path preferentially progressing at the interface between sand grains and cement paste, but not limited to these regions. A considerable amount of energy must be dissipated in creating the tortuous crack surface and in multiple or branch cracking. This technique permits resolution of much finer cracks than can be detected with ordinary optical methods.
55 citations
TL;DR: In this paper, the effectiveness of seven pulverized-fuel ashes (pfa) and a ground granulated blastfurnace slag (gbfs) in reducing the expansion and cracking induced in mortar bars by the alkali-silica reaction is described.
Abstract: Synopsis The effectiveness of seven pulverized-fuel ashes(pfa) and a ground granulated blastfurnace slag (gbfs) in reducing the expansion and cracking induced in mortar bars by the alkali–silica reaction is described. The proportion of reactive aggregate in the mortar bars was such that the water-soluble alkali to reactive silica ratio lay close to its critical value. It is shown that the partial replacement of a high-alkali cement by either pfa or gbfs reduces the expansion induced by the alkali-silica reaction and that with high-cement-content mixes it is necessary to replace more than 40% of the cement by pfa or gbfs to prevent damage from occurring due to the alkali-silica reaction. It is concluded that both materials act effectively asalkali diluters, gbfs being more effective in reducing damage due to the alkali-silica reaction than pfa.
33 citations
TL;DR: In this paper, a loading frame for compressive loading of small specimens of hardened cement paste or mortar within the specimen chamber of a scanning electron microscope is described, and some preliminary results of observations made with the device are described.
30 citations
Patent•
29 Sep 1982
TL;DR: In this paper, an improved version of the slag-dust mixture is described, which is a mixture of ground calcium carbonate or Portland cement kiln dust, or both, and ground, granulated blast furnace slag.
Abstract: An improved cement for making concrete and mortar comprises a blend of ground calcium carbonate or Portland cement kiln dust, or both, and ground, granulated blast furnace slag. While its physical and chemical characteristics differ from Portland cement, it is a functional substitute for Portland cement and may be used in combination with Portland cement in a wide range of proportions. The hardening and other characteristics of this slag-dust cement can be improved by the addition of SO 3 , ordinarily by adding ground gypsum and by the use of accelerators and high-range water reducing formaldehyde compounds.
Patent•
12 Oct 1982
TL;DR: For the acceleration of the setting and of the hardening of a hydraulic binding agent such as cement, limestone, hydraulic limestone and gypsum as well as mortar and concrete prepared thereof, are added to the mixture, which contains said binding agent, from 0.5 to 10 percent by weight as discussed by the authors.
Abstract: For the acceleration of the setting and of the hardening of a hydraulic binding agent such as cement, limestone, hydraulic limestone and gypsum as well as mortar and concrete prepared thereof, are added to the mixture, which contains said binding agent, from 0.5 to 10 percent by weight, referred to the weight of this binding agent, of an alkali-free setting- and hardening-accelerator, whereby this accelerator contains aluminum hydroxide.
Patent•
03 Jun 1982
TL;DR: In this article, a muzzle loading mortar is constructed for mounting on a protected enclosure, for example, an armored vehicle, which includes a mortar tube having an open end for receiving and discharging a projectile, and mounting means, including a tube cradle connected with a recoil return means, are provided for mounting the tube on the enclosure.
Abstract: A muzzle loading mortar constructed for mounting on a protected enclosure, for example, an armored vehicle. The mortar includes a mortar tube having an open end for receiving and discharging a projectile, and mounting means, including a tube cradle connected with a recoil-return means, are provided for mounting the tube on the enclosure. The recoil-return means includes a hydraulic member which cooperates with a spring for reducing the forces introduced into the enclosure during development of a shot from the mortar. A loading means is mounted for relative movement between the open end of the tube and the protected enclosure for muzzle loading the open end of the tube with a projectile. The loading means can be operated from within the protected enclosure to load a projectile into the mortar tube.
01 Jan 1982
TL;DR: In this paper, eight mortar standards of known composition were prepared and used to test the accuracy and applicability of three chemical techniques widely used to analyze historic mortars, and the results indicated that only one of these techniques can be considered reliable when used to examine a broad range of historic Mortars.
Abstract: Summary Eight mortar standards of known composition were prepared and used to test the accuracy and applicability of three chemical techniques widely used to analyze historic mortars. The results indicated that only one of these techniques can be considered reliable when used to examine a broad range of historic mortars.
Patent•
01 Jun 1982TL;DR: A storable cement product is a dry mixture of magnesium oxide and aluminum phosphate, or a product containing MgO and, separated therefrom, an aqueous aluminum phosphate solution, some or all of an inert aggregate component optionally being present in either product as discussed by the authors.
Abstract: A storable cement product is a dry mixture of magnesium oxide (MgO) and aluminum phosphate, or a product containing MgO and, separated therefrom, an aqueous aluminum phosphate solution, some or all of an inert aggregate component optionally being present in either product. In 45-kg samples, the mortar formed when the MgO, phosphate, water, and aggregate are combined attains an exotherm in the range of about 40°-90° C. after an interval of 10 minutes. The mortar hardens quickly thereafter, and is uniquely suited for patching roads under varying conditions of application and use. The reaction exotherm is controlled by a unique combination of the concentrations of the four critical components, and the surface area and particle size of the MgO.
Patent•
11 Feb 1982
TL;DR: In this paper, a set of inner rotating vanes are used to throw mortar onto an outwardly flared conical surface and the mortar travels along the surface to the outer vanes on its outer edge from which the mortar is thrown in a high velocity, dense stream against the pipe wall.
Abstract: A distributor head for throwing mortar onto the wall of a pipe (12) being lined. A set of inner rotating vanes (56) throw the mortar onto an outwardly flared conical surface (40 ) and the mortar travels along the surface (40) to the outer vanes (48) on its outer edge from which the mortar is thrown in a high velocity, dense stream against the pipe wall. The inner vanes are individually and releasably fitted into a collar (60) at the inner edge of the flared conical surface.
Patent•
20 Apr 1982TL;DR: In this paper, dry-set mortar compositions adapted to be mixed with water containing, in the dry state, sand, Portland cement and a cellulose ether improved by the inclusion of anionic polyacrylamide and Bentonite clay.
Abstract: Dry-set mortar compositions adapted to be mixed with water containing, in the dry state, sand, Portland cement and a cellulose ether improved by the inclusion of anionic polyacrylamide and Bentonite Clay.
Patent•
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28 Apr 1982
TL;DR: The self-flowing and self-levelling fluid screeds save all these working steps, by means of simple casting or pumping as discussed by the authors, by using particularly cheap additives, which allow masses free of strains and cracks to be produced.
Abstract: The classical method for laying cement screeds is very time-consuming, because the individual working steps involve laborious spreading, compacting, skimming and smoothing. The self-flowing and self-levelling fluid screeds save all these working steps, by means of simple casting or pumping. The invention relates to the composition of a mortar, using particularly cheap additives, which allow masses free of strains and cracks to be produced. According to the invention, this object is achieved by replacing the Portland cement, which greatly shrinks during solidification and hardening, by an easily expanding binder mixture. In addition to the Portland cement, the binder mixture also contains alumina cement, calcium sulphate, hydrated lime and hydraulic additives.
Journal Article•
TL;DR: In this article, small bars made of cement paste and mortar, conditioned in various climates were after conditioning analyzed for the substances C1 and OH and the results have been used to calculate the chloride bounding capacity and effective diffusion coefficients for different qualities.
Abstract: Small bars made of cement paste and mortar, conditioned in various climates were after conditioning analyzed for the substances C1 and OH. The measurements were made on a pore solution which had been pressed out of these specimens. The results have been used to calculate the chloride bounding capacity and effective diffusion coefficients for different qualities. (Author)
Patent•
24 Sep 1982
TL;DR: Particles of a coloring agent having opaque sheaths, which are the color of a mortar mass, are introduced into the reactive mortar mass to signal the distribution of hardener therein this paper.
Abstract: Particles of a coloring agent having opaque sheaths which are the color of a mortar mass, are introduced into the reactive mortar mass to signal the distribution of hardener therein.
Patent•
30 Jul 1982
TL;DR: The inclusion of fibre elements in a sulphur/mineral aggregate composition, such as a sulfur concrete or mortar, improves fracture toughness of the composition and retards crack propagation as discussed by the authors.
Abstract: The inclusion of fibre elements in a sulphur/mineral aggregate composition, for example, a sulphur concrete or mortar, improves the fracture toughness of the composition and retards crack propagation.
Patent•
05 Nov 1982
TL;DR: A concrete panel support for underground mining and tunnelling, in arch or closed-circle configuration, with yielding elements made of concrete mortar arranged between said panels, characterized in that tubes (3) are arranged vertically to the roadside (7) in said yielding elements as discussed by the authors.
Abstract: 1. A concrete panel support for underground mining and tunnelling, in arch or closed-circle configuration, with yielding elements made of concrete mortar arranged between said panels, characterized in that tubes (3) are arranged vertically to the roadside (7) in said yielding elements.
Patent•
16 Oct 1982
TL;DR: In this article, a mixture of 60-88 % by weight of paraffin hydrocarbons having a chain length of 10 to 20 C atoms and/or of glyceryl esters of higher fatty acids and 40-12 % of surfactants, prior to mixing with the binders is used.
Abstract: A cement- or gypsum-based dry mortar containing porous light-weight materials, which contains 0.05-1.0 % by volume, based on the volume of the dry mortar, of a mixture of 60-88 % by weight of a mixture of paraffin hydrocarbons having a chain length of 10 to 20 C atoms and/or of glyceryl esters of higher fatty acids and 40-12 % by weight of surfactants. At least 33-5 % by weight of the surfactants must be amines, amides or ammonium salts. In the process for the preparation of the dry mortar, one of the additives is wet with 0.05-1.0 % by volume, based on the volume of the dry mortar, of a mixture of 60-88 % by weight of a mixture of paraffin hydrocarbons having a chain length of 10 to 20 C atoms and/or of glyceryl esters of higher fatty acids and 40-12 % by weight of surfactants, prior to mixing with the binders. The dry mortar obtained exhibits no separation or only slight separation.
TL;DR: In this article, the effect of the initial rate of absorption (IRA) of structural clay units on the bonding ability of mortars to those units was examined and a summary of data for both small-scale prisms and full-size walls from several sources.
Abstract: An examination is made of the effect of the initial rate of absorption (IRA) of structural clay units on the bonding ability of mortars to those units. This paper examines relatively recent data on the effect of IRA on the bond between mortar and structural clay masonry units. Included is a summary of data for both small-scale prisms and full-size walls from several sources. The paper also suggests areas and methods of research to more specifically identify the mechanisms of mortar bond to brick and other clay masonry units.
TL;DR: The results of water permeance tests on twelve walls before and after coating with a proprietary clear water repellant are reported as discussed by the authors, which revealed a significant reduction in the amount of leakage, an increase in the time required to achieve maximum rate of leakage and a decrease in the percentage of damp area.
Abstract: The results of water permeance tests on twelve walls before and after coating with a proprietary clear water repellant are reported. Half of the single-wythe walls were brick; and other half, normal-weight concrete masonry units. Half of the walls used masonry cement mortar; the other half, portland cement-lime mortar. Comparison of results revealed a significant reduction in the amount of leakage, an increase in the amount of time required to achieve maximum rate of leakage, and a decrease in the percentage of damp area as a result of the application of the coating. The walls will be retested after six months of outdoor exposure.
TL;DR: In this article, the durability performance of polymer-modified mortars has been extensively studied and the results demonstrate that most polymer modified mortars have better durability performance than conventional cement mortar.
Abstract: Polymer-modified mortars have recently been widely used in construction work throughout the world because of their high strength, excellent adhesion, waterproofness, and chemical resistance. The durability performance of such mortars has not been extensively studied until now. Polymer-modified mortars using various polymer dispersions were prepared with different polymer-cement ratios and tested for weatherability, freezing-thawing resistance, heat resistance, and chemical resistance. The test results demonstrate that most polymer-modified mortars have better durability performance than conventional cement mortar.
Patent•
25 Feb 1982TL;DR: In this paper, the layer of distressed concrete around the metal reinforcement is removed and a high-content calcium nitrite-containing cement based composition is used to fill the removed area.
Abstract: Reinforced concrete structures often suffer corrosion damage. This damage is repaired by removing the layer of distressed concrete around the metal reinforcement and filling in the removed area with a high content calcium nitrite-containing cement based composition.
Patent•
29 Sep 1982
TL;DR: In this article, a level-regulated base plate is placed between the base plate and the foundation, and a non-shrink cement mortar is poured between base plate 6 and foundation concrete.
Abstract: PURPOSE:To increase the strength of cement mortar by a method in which chain links are set on a concrete foundation, a level-regulated base plate is set on the chain links, and cement mortar is placed between the base plate and the foundation. CONSTITUTION:A chain link 11 for reinforcing cement mortar is set on a concrete foundation 3, and a base plate 6 is set at a given interval between the base 6 and the concrete foundation face 3a. In this case, the regulation of the level is made through a spacer by fixing the spacer to the place where the level is to be regulated by clamping a nut 9 screwed with an anchor bolt 1. Afterwards, a non- shrink cement mortar 10 is poured between the base plate 6 and the foundation concrete 2. Since the chain link 11 is buried in the cement mortar 10, the strength of the mortar 10 is increased and the foundation which can sufficiently withstand earthquake, etc., for spherical tank, etc., can thus be constructed.
Journal Article•
TL;DR: In this article, changes in compressive and flexural strength of slag mortar due to different curing conditions have been investigated and the influence of water curing, air curing and alternating curing in water and air have been studied.
Abstract: Changes in compressive and flexural strength of alkali activated mortar due to different curing conditions have been investigated. Influence of water curing, air curing and alternating curing in water and air have been studied. Relations between flexural strength, changes in water content and deformations of alkali activated slag mortar at alternating curing conditions have been analyzed and compared with those of slag cement and portland cement mortars. (Author)