Papers by Keyword: Test Method

Abstract: In this paper, the effects of different sample clamping modes, curing time of the adhesive during sample preparation, gauge length of the sample and tensile rate on the tensile properties of continuous alumina fiber bundles are briefly introduced. These parameters can accurately affect the tensile properties of alumina fiber bundles.

Abstract: The carbonation process in alkali-activated slag cement concrete is more complicated. This paper reviews the research progress of carbonation resistance of alkali-activated slag cement concrete at home and abroad and summarizes the existing research on carbonation. The focus is on the carbonation mechanism, test methods, influencing factors and the effect of carbonation on the performance of alkali-activated slag cement concrete. The problems existing in the current research on the anti-carbonation property of alkali-activated slag cement concrete and the issues for further research are proposed.

Abstract: The article analyzes the change in the stress-strain state of ceramic brick samples when tested in compression, depending on the variable parameters - the type of sample and the method of surface preparation. The experiment showed that the friction forces arising in the “sample-plate test press” zone of contact have a significant effect on the deformation conditions of the samples and lead to an uneven distribution of the breaking load over the surface. This in turn leads to an overestimation of the strength characteristics of the lot, and, consequently, to errors in the calculations of the bearing capacity of the structures. A numerical analysis of the stress distribution also showed that for the samples aligned by grinding and with the help of a mortar; the effect of compression caused by friction forces can be traced. Thus, the results of the numerical experiment are in good agreement with the results of the full-scale experiment. To increase the reliability of the test results, it is necessary to reduce the influence of friction forces and provide conditions for the realization of uniaxial compression. In this regard, it is necessary to adjust the standard test method, namely to use the technical felt gaskets as a method of preparing the surface.

Abstract: Structural retrofitting with composite materials proved to be an effective technique for rehabilitation of degraded or damaged masonry and concrete buildings. Nowadays, Fiber Reinforced Cementitious Matrix (FRCM) composites are widely used as externally bonded strengthening systems thanks to their high performance, low weight and easiness of installation. Several experimental tests and numerical studies are currently available concerning the tensile and bond behavior of FRCM systems, but a debated and still open issue concerns the methods for the mechanical characterization of the mortar used as matrix within the strengthening system. The present paper analyses and compares different test methods for determining the matrix tensile strength. Pure tensile and flexural tests have been carried out on different mortar matrix samples. In order to evaluate which is the most suitable value to be considered for a correct interpretation and modeling of the composite system, the experimental results obtained through flexural tests on standard mortar specimens have been compared with the outcomes obtained from direct tensile tests on FRCM coupons. The present study represents only a first step for the definition of the most appropriate test method for the mechanical characterization of the matrix used within FRCM strengthening systems.

Abstract: New technical applications and the ongoing infrastructural and industrial development of regions with extreme climatic conditions place ever greater demands on the properties of the materials used. On the one hand conventional materials can often meet such demands only to a limited extent whilst, on the other, a lack of experience means that sometimes no solid conclusions can be drawn regarding their suitability under extreme conditions. The examination of the influence of extreme environmental conditions on the behaviour of the material and the development of innovative materials with a tailored profile of properties is therefore one of the main tasks of modern material research as well as the material manufacturing and processing industry.

Abstract: A Negative pressure sensing set-up for capillary pressure test was designed and used for testing the capillary pressure of cement-based materials, cement pastes of water-cement ratio 0.30 was adopted, and the factors that may affect the measured values such as hardness of water tube, gas volume in the set-up, gas content in water, test depth, bleeding of cement pastes was studied. The results shows that the accuracy of the measured value is very large impacted by the air volume in the set-up and by the hardness of water tube, the capillary pressure at different depths could be affected by the external environment and the bleeding of cement pastes. According to the test results, methods for measuring the capillary pressure of cement-based materials were proposed, and some other recommendations that help to improve the test accuracy were given.

Abstract: Aluminum-plastic composite panel is a kind of new type energy-saving and environmental-friendly curtain wall decorative material, and is widely used in building exterior wall, curtain wall board, old building reconstruction and renovation and other projects. With the development and improvement of production and application technology, the performance and functions of aluminum-plastic composite panel products have been optimized continuously; especially at present, all countries in the world have more and more strict requirements on fire safety, and the fire safety standards of buildings also have been improved continuously. In this context, all the manufacturing enterprises have been actively developing new techniques to produce new type aluminum-plastic composite panels, and have significantly improved the fireproof and flame-retardant properties of the products on the basis of ensuring all the performance levels of the products being acceptable. This paper proposes optimal design suggestions via detection analysis on three groups of aluminum-plastic composite panel samples, and is of important practical significance to the research and development of the aluminum-plastic composite panel with low-combustion-heat and flame-retardant core material.

Abstract: Aggregate-mortar interface transition zone is a major factor for mechanical properties and durability of materials. Owing to the distinctive features of interface transition zone, this study reviewed research methods, structure models, improving methods and the influence to mechanics and durability of concrete of this zone. We also analyzed various test methods which are referred to in this review and their applicability, and discussed the formation mechanism and improving approach for interface transition zone. Our investigation suggested further scientific test is necessary for researching mechanical property of the interface.

Abstract: The building sand is mainly composed of river sand at early stage. Recently, with the depletion of river sand, the new mined river sand cannot meet the demands for building sand. The sea sand is resourceful and can remedy the deficiency of sand for construction. However, the sea sand contains high content of chlorine salt, shell and lightweight matters. They are harmful for the strength and durability of concrete and will lead to premature corrosion of rebar. This will endanger the safety of construction. The studies demonstrate that high content of chlorine salt in sea sand is the main factor led to the deterioration of sea sand concrete. Therefore, in order to ensure the safety of construction, the threshold value of chloride content is specified in standards about concrete and aggregate. And methods testing the content of chloride ions are provided. However, the criterion in different standards differs from one another, which means their different viewpoints about the harm of chloride ions. In this work, the threshold value and test methods of chloride ion content for the building sand in the national standards and the international standards are summarized. The research has great significant for setting standards about sea sand, determining the rational threshold value of chloride ion content and improving the method testing the content of chloride ions.

Abstract: The article presents a description of the impact block shear test method of adhesive joints. Based on ISO 9653 and literature a pendulum machine was upgraded to make impact strength tests of adhesive joints and validation studies were conducted to determine the parameters of instrumentation and block samples. As a result of the experiments a range of the usable length of the adhesive joint and methods of adhesive joints preparation was selected, and it was determined the adopted method of attachment of the sample in the holder and the pendulum durability. A series of tests on adhesive joints were conducted using samples bonded of adhesive composition Epidian 57 with Z1 hardener for one bondline thickness. Preliminary findings from the research will be used in subsequent, relevant research.