Showing papers on "Mortar published in 1990"
TL;DR: In this article, the authors discuss the mechanism of plastic shrinkage in portland cement and portland cements-silica fume paste and mortar, and the effects of the three delivery forms of silica fumes; as well as densified powder, densified powders, and slurry, on plastic shrinkages are presented.
157 citations
01 Jan 1990
133 citations
TL;DR: In this paper, the strain-rate sensitivity of the cement paste and mortar constituents of concrete is studied experimentally, in terms of the initial elastic moduli, maximum stress, and corresponding strain.
Abstract: The strain-rate sensitivity of the cement paste and mortar constituents of concrete is studied experimentally. Saturated cement paste and mortar specimens are loaded in compression to 15,000 microstrains, 27 to 29 days after casting, using strain rates ranging from 0.3 to 300,000 microstrains/sec. Water-cement ratios of 0.3, 0.4, and 0.5 are used. Strain-rate sensitivity of the material is measured in terms of the initial elastic moduli, maximum stress, and corresponding strain. The initial elastic moduli and the strength of cement paste and mortar increase by 7% and 15%, respectively, with each order of magnitude increase in strain rate. The strain at the maximum stress is the greatest for the lowest strain rate. With an increase in strain rate, the strain at the maximum stress first decreases and then increases.
90 citations
TL;DR: In this article, the use of ultrasonic pulse attenuation (UPA) as a non-destructive testing parameter to evaluate the quality of material is presented, which is a combined effect of the geometric dispersion and energy dissipation.
87 citations
TL;DR: In this paper, an experimental study of synthetic fiber reinforced mortar is presented. The fibers used included aramid, high-strength high-modulus polyethylene, and polypropylene, and they were randomly mixed in the matrix at volume fractions below 3%.
Abstract: This paper reports on an experimental study of synthetic fiber reinforced mortar. The fibers used included aramid, high-strength high-modulus polyethylene, and polypropylene, and they were randomly mixed in the matrix at volume fractions below 3%. Tensile properties of the composites were measured by the direct tensile test under both monotonic and cyclic loading. Workability and the drying shrinkage of the composites are also reported.
78 citations
TL;DR: In this article, the sulfate resistance of concrete made with portland cements partially replaced by a separately ground, pelletized slag was evaluated using a large 2-part series of 23 different mortar mixes using a method similar to the later standardized ASTM C 1012 test procedure.
Abstract: Tests to evaluate the sulfate resistance of concrete made with portland cement partially replaced by a separately ground, pelletized slag were initiated in 1977. Over 1000 cylinders were cast from 8 different concrete mixes made with normal and sulfate resisting portland cements, and 45, 65, and 72 % slag replacement. These were exposed to water and different strengths of sulfate solutions for 8 years, after which some were exposed to accelerated SO4 solutions. These tests were augmented by a large 2-part series of more than 23 different mortar mixes using a method similar to the later standardized ASTM C 1012 test procedure. These mortar bars were exposed to deionized water and various sulfate solutions. Variables included C3A content of portland cements, slag replacement level, alumina content of slag, sulfate salt type and compressive strength at first exposure.
53 citations
TL;DR: In this article, three types of synthetic fiber are used to demonstrate a test proceudre for quantifying the effect of the fiber addition on both shrinkage and crack control, and are compared to non-fibrous control samples.
Abstract: Fibrous concrete (FRC) made with synthetic fibers has been shown to be a cost-effective treatment for improving certain strength, toughness, and crack-resistance properties of otherwise brittle portland cement concrete (PCC). Three types of synthetic fiber are used in this study to demonstrate a test proceudre for quantifying the effect of the fiber addition on both shrinkage and crack control, and are compared to nonfibrous control samples. The benefits resuting from the use of synthetic fibers are shown.
52 citations
TL;DR: In this paper, a multi-layered ring model of prestressed concrete pipe is presented for analysis of such pipe under the combined effects of internal fluid pressure, external load, and pipe and fluid weights.
Abstract: A method based on a multi‐layered ring model of prestressed concrete pipe is presented for analysis of such pipe under the combined effects of internal fluid pressure, external load, and pipe and fluid weights. This method considers the nonlinear properties of the concrete core, mortar coating, prestressing steel wire, and steel cylinder. In particular, it accounts for tensile strain softening and cracking of core concrete and coating mortar, and the redistribution of moment that results from the changes of stiffness around the pipe. The combined loads corresponding to certain serviceability, elastic, and strength limit states are calculated. The calculated combined loads at the onset of visible core and coating cracks are compared to the results of tests conducted on six embedded‐ and lined‐cylinder pipes. The comparison shows good agreement. Significant moment redistribution from invert and crown to springline is shown to occur at combined loads that result in softening of core concrete at the invert an...
43 citations
TL;DR: In this paper, two studies on sulfate resistance of blended cements are presented, one on the effect of pozzolan addition and the other on the relation between flexural strength development and sulfate resistances of these cements.
41 citations
TL;DR: The ViscoCorder as mentioned in this paper is a small variable speed consistometer that can be used to determine the rheology of fresh mortar, and it shows that the downcurve conforms to the Bingham model, and that two parameters, yield value and plastic viscosity, are required to characterize it.
Abstract: The ViscoCorder is a small variable speed consistometer that can be used to determine the rheology of fresh mortar. It shows that the downcurve conforms to the Bingham model, and that two parameters, yield value and plastic viscosity, are required to characterize it. When the instrument is calibrated with model fluids these parameters can be calculated in fundamental units. The range of numerical values obtained agrees well with exiting data.
41 citations
TL;DR: In this article, the authors used holographic interferometry to determine the fracture process zone of mortar and concrete and found that the larger the aggregates, the more pronounced is this fracture process region.
TL;DR: In this article, a large number of 40x40x160 mm mortar prisms were cast using one of two sand types: Nymoelle and Kallerup, in each case the mortar had the following composition: 1 part low alkali Portland cement, 3 parts sand and 0.5 part water by weight.
TL;DR: In this article, 29Si magic-angle-spinning nuclear magnetic resonance measurements were used to trace the cement hydration process in cement paste and mortar specimens made from ordinary portland cement, type I.
Abstract: This paper presents 29Si magic-angle-spinning nuclear magnetic resonance measurements that trace the cement hydration process in cement paste and mortar specimens made from ordinary portland cement, type I. These specimens were moist-cured for 3, 7, 14, and 28/31 d at temperatures ranging from 21° to 80°C. Compressive strength for all tested specimens was also determined. The results show that the degree of hydration (Q1+Q2) and the compressive strength increase with curing times and temperatures. However, at 80°C, the compressive strength decreases while the degree of hydration increases.
TL;DR: In this paper, the authors measured the sulphate resistance of concretes containing various levels of chloride introduced in the mixing water by immersion in sodium sulphate and magnesium sulphate solutions.
Abstract: The sulphate resistance of concretes containing various levels of chloride introduced in the mixing water was assessed by immersion in sodium sulphate and magnesium sulphate solutions. Mortar and concrete cubes were made using ordinary Portland cement (OPC) and sulphate-resisting Portland cement (SRPC) with chloride contents of 0–4·5%; the chloride was introduced in a salt of either sodium or calcium. Deterioration was monitored by comparing the strength of cubes in sulphate solutions with that of similar cubes stored in water over a period of 7 years for concrete and of 1 year for mortar. The 100 mm concrete cubes (which were also assessed visually at 3 and 7 years) were made with two levels of cement content (225 and 335 kg/m3). A 1:3 cement/sand mix was used for the 12·5 mm mortar cubes. The results over 1 year for the mortar cubes showed that chloride had either a negligible or a generally beneficial effect on the resistance to sulphate attack for both OPC and SRPC. A similar overall trend was observe...
Patent•
23 Oct 1990TL;DR: In this article, the authors used a vinyl ester-urethane resin to improve the strength properties of anchor rods in solid receiving materials, which may have been pre-accelerated.
Abstract: For fixing anchorage means such as anchor rods in solid receiving materials without expansion pressure, mortar compositions are used which consist of a hardener and a resin. To improve the strength properties, a vinyl ester-urethane resin is used which may have been pre-accelerated.
Patent•
30 Apr 1990
TL;DR: In this paper, an iron pipe and other hollow articles are lined with a cementitious mortar containing a quantity of polymer particles and the pipe is rotated about its axis so as to stratify the mortar and develop a polymer rich inner surface that is subsequently cured, dried and heated to the polymer fusion temperature.
Abstract: Iron pipe and other hollow articles are lined with a cementitious mortar containing a quantity of polymer particles and the pipe is rotated about its axis so as to stratify the mortar and develop a polymer rich inner surface that is subsequently cured, dried and heated to the polymer fusion temperature and then coated with a continuous layer of pure polymer.
01 Jan 1990
Journal Article•
TL;DR: In this paper, the flexural load-deflection curves for mortar reinforced with various fiber types (steel and synthetic) and various fiber volume fractions are measured using 3 diffenect beam sizes.
Abstract: The flexural load-deflection curves for mortar reinforced with various fiber types (steel and synthetic) and various fiber volume fractions are measured using 3 diffenect beam sizes. Three new flexural toughness indexes that reflect the general shape of the load-deflection curve are defined and calculated. The flexural strength/tensile strenth ratio f subf/f sub t is proposed as a parameter that reflects material brittleness - lower value for a more brittle material. The results are discussed.
TL;DR: Samples obtained from dry mortar powder and from mortar in buildings where casein was used and from control buildings were found to contain microorganisms, e.g., Bacillus, Clostridium, Micrococcus, and Propionibacterium, and Fungi; no evidence of bacterial degradation was found.
Abstract: In newly constructed houses and buildings in which self-leveling mortar containing casein has been used, residents and office employees have noted a bad odor and have complained of headache, eye and throat irritation, and tiredness. These problems were suspected to result from the degradation products emitted from the mortar. Samples obtained from dry mortar powder and from mortar in buildings where casein was used and from control buildings were found to contain microorganisms (mean of 10(2) culture forming units/g). Environmental species were predominantly found, e.g., Bacillus, Clostridium, Micrococcus, and Propionibacterium. Fungi were found occasionally; no evidence of bacterial degradation was found. Headspace and gas chromatographic-mass spectrometric analysis of air from the newly constructed houses and from hydroxide-degraded casein revealed the presence of amines in the 0.003-0.013 ppm range and the presence of ammonia and sulfhydryl compounds, all of which in low concentrations can cause the symptoms observed. These substances, however, were not detected in control buildings.
TL;DR: In this paper, a model for the expansion of a silica glass/alkaline OPC mortar was developed based on the observation that the main reaction product of the glass is a layer of CSH gel formed at its surface.
TL;DR: In this paper, a study was conducted to determine the effects of using kiln dust (a pozzolonic waste byproduct of cement manufacture) as a cost reducing additive in blended cements.
TL;DR: In this article, a simplified model was developed to relate the internal structure and mechanisms of deformations to the post-peak behavior and fracture toughness of concrete, and the authors showed that the branching of an interfacial crack into the mortar may form a dominant crack which leads to the eventual fracture plane.
Patent•
13 Mar 1990
TL;DR: In this article, a mixture of crushed pumice, type S mortar and glass fibers is used to form a waterproof, high strength, hard material having good insulation properties, which forms the hard material upon the addition of water and after allowing the mixture to cure.
Abstract: A composition for forming a waterproof, high strength, hard material having good insulation properties, comprising a mixture of crushed pumice, type S mortar and glass fibers, which forms the hard material upon the addition of water and after allowing the mixture to cure. The material has superior insulation properties to conventional compositions formed using portland cement instead of type S mortar.
TL;DR: In this article, the authors reported the findings on the durability of laterized concrete and laterite-cement mortar specimens in terms of permeability and chemical attack on such specimens.
27 Sep 1990
TL;DR: In this paper, the expansion of mortar bars containing silica glass and alkaline ordinary Portland cement has been studied as a function of alkali content, proportion of silicaglass in the aggregate, silica Glass/Cement ratio, glass particle size, alkali compound used and temperature.
Abstract: The expansion of mortar bars containing silica glass and alkaline ordinary Portland cement has been studied as afunction of alkali content, proportion of silica glass in the aggregate, silica glass/cement ratio, silica glass particle size, alkali compound used and temperature. Pessimum effects have been found in relation to the effect of alkali content, glass/cement ratio and particle size. It is suggested that these pessimum effects can be related to a pessimum (effective SiO2/Na2O equivalent) ratio.
01 Jan 1990
TL;DR: In this paper, a test method that accurately measures the strength of the bond of latex modified mortar and concrete to conventional concrete is described, using 3.5 in. diameter cylinders of concrete as the base material and standard 3 in.5 diameter steel pipe nipples as molds.
Abstract: The paper describes a test method that accurately measures the strength of the bond of latex modified mortar and concrete to conventional concrete. Using 3 in. diameter cylinders of concrete as the base material and standard 3 in. diameter steel pipe nipples as molds, an overlay of the latex modified material is applied and cured similar to field conditions and then tested in direct tension. The results not only give values of the bond strength of the overlay tested but also clearly indicate whether the failure is in the bond or the materials tested. This test also has potential for application to other nonlatex-modified systems.
Patent•
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06 Jul 1990
TL;DR: A ready-mix mortar based on mineral binders such as hydraulic binders and hydrated lime, mineral sand aggregates, granulated solvated calcium silicate as light aggregate, additives and additive agents for improving the material properties was proposed in this paper.
Abstract: The invention relates to a ready-mix mortar based on mineral binders such as hydraulic binders and hydrated lime, mineral sand aggregates, granulated solvated calcium silicate as light aggregate, additives and additive agents for improving the material properties.
TL;DR: In this paper, the behaviour of high volume percentage steel fiber mortar specimens subjected to flexure was reported. And the results of the investigation indicate that with 8% high volume, steel fibre mortar specimens possess a flexural strength of about 40 MPa.
Abstract: Tests are reported on the behaviour of high volume percentage steel fibre mortar specimens subjected to flexure. Flexural and cyclic load tests were conducted; in addition, comparison tests were made on conventional fibre mortar and ferrocement specimens. Both strength and deflection characteristics were studied. The results of the investigation indicate that with 8% high volume, steel fibre mortar specimens possess a flexural strength of about 40 MPa.