Papers by Keyword: Splitting Strength

Abstract: Ceramsite cellular concrete (CCC for short) is a kind of lightweight aggregate concrete. In this paper, the selection of materials and design of mix proportion have been discussed, and basic property tests has been done. The compressive strength was proved up to the National Standards of P. R. GB50003-2001(code for design of masonry structures), furthermore, elastic modulus and Poisson's ratio were also introduced. Questions remain regarding the quality control of the product, and further work is needed to resolve this contradiction.

Abstract: Adding the glass will make the cohesion property of HMA (Hot Mix Asphalt) worse. we often improve the antistrip performance of conventional HMA by the means of adding hydrated lime. In this article, we compare the effect of two different patterns of adding hydrated lime. The test reveals that: replacing the mineral power with hydrated lime can improve the overall performance of mix; With respect to mixing the hydrated lime with asphalt in advance, the water stability of concrete increase more, if the mineral power is replaced by equivalent; Although it can’t do a favor to the mix’s low temperature performance, mixing the hydrated lime with asphalt in advance can significantly improve the high temperature performance, it can be used in high temperature region while it rains rarely.

Abstract: In order to realize effective detection of the splitting strength of shallow asphalt pavement, using the self-researched and developed Strength Detector of Shallow Pavement, researched deep into the change regulation between shallow pavement strength and temperature by laboratory and spot penetrating experiments in multiple temperatures. First of all, the splitting strength is found to be a linear function of the average penetrating depth; Secondly, on the basis of temperature and average penetrating depth equivalence principle, obtained the master curve of the splitting strength by translation and fitting. Established a unified and practical test standard for the Strength Detector of Shallow Pavement; At last, analyzed the spot penetrating experiments data of three different types of asphalt pavement in Harbin district. The results show that the splitting strength curve of asphalt pavement in Harbin district appear a deep V-shaped character from April to October. The differentials between splitting strength of the three different types of asphalt pavement maximize in July.

Abstract: The splitting tensile method for the tensile strength of concrete is usually used in structural applications, so it is great important in the investigating the relation between the direct tensile strength and the splitting strength. But the relationship between the splitting strength and the direct tensile strength is not consolidatly confirmed at home and abroad. In order to obtain the exact results, the experimental apparatus for concrete of the direct tension are designed, which resolves the difficulty of ensuring that the load is truly axial. Tests of the direct tension are performanced on three different concrete mixes (C20,C40,C60) at 3, 7, 14 , 28 and 60 days and the test data do not scatter. The relations between the tensile strength and the cube compressive strength are obtained and a formula for investigating the relation between the direct tensile strength and the splitting strength are proposed.

Abstract: In this paper, according to the national standard and testing methods,the direct tension strength,splitting tensile strength and cubic compressive strength test were carried out for 8 different groups of hybrid fiber (containing steel fiber, macro-polypropylene fiber and dura fiber) reinforced HPC specimens.The results showed that when the volume proportion of ternary hybrid fiber was less than 1%, there was not obvious influence for the concrete compressive strength, but the splitting tensile strength increased by 26% ~ 69%; the ratio between splitting tensile strength and compressive strength for HFRC increased to 1/12~1/9. When added 0.7% steel fiber, 0.19% macro-polypropylene fiber and 0.11% dura fiber, the confounding effect was the best. Based on the advantages and disadvantages of tensile splitting strength and direct tensile strength test and the results of tests, the concept of equivalent tensile strength and calculative formula was put forward .

Abstract: In order to acquire axial tensile stress-strain curve of HFRC, specimens of equal cross-sections with embedded screw and pasted with carbon fiber cloth in corresponding length were tested on closed-loop electro-hydraulic servo testing machine which a subsidiary rigid frame was attached to. The effect of fiber volume, steel fiber slenderness ratio, steel fiber type and active admixture on the tensile properties of HFRC with low volume fraction was studied. The results indicate that when total volume proportion is less than 1% the first crack strength and ultimate tensile strength of HFRC can increase more than 15% and about 40% , respectively, the difference of effect of arched steel fiber and crimped steel fiber on the tensile behavior is small. The tensile behavior of HFRC is the best with a combination of slenderness ratio of 80 and 47.1kg/m³ arched steel fiber, 2.6kg/m³ macro-polypropylene fiber and1.0kg/m³ dura fiber and 10% .

Abstract: The mechanical strengths of self-compacting concrete (SCC) with different strengths and different fibers were investigated. By mechanics performance testing on concrete samples, it shows that the fiber can significantly reduce strength of the self-compacting concrete during curing period. The 28d tensile strength of self-compacting concrete can be improved when steel fiber, polypropylene fiber, or polyethylene fiber were used. Moreover, steel fiber can improve the 28d compressive strength; contrarily, polypropylene fiber and polyethylene fiber can reduce the 28d compressive strength.

Abstract: This study investigated the influence of crystalline sealers and curing environment on compressive strength, splitting strength and elastic modulus of cement-based composites. Four kinds of crystalline sealers addition (0 %, 3 %, 5 % and 7 %) were used in the concrete specimens. SEM observations were assisted in verifying the results of mechanical properties. The test results demonstrated that the specimens increased the mechanical properties with the inclusion of crystalline sealers increased. The crystalline sealers reacted with cement to produce the crystals and hydrations, which could fill with the pore and supply a denser microstructure. This appearance was verified by the SEM micrographs. In inclusion, the cement-based composites containing 7 % crystalline sealers seem to give superior mechanical properties, and make the pores become finer and enhance the durability.

Abstract: Influence of replacement ratio and water-cement ratio on the recycled concrete mechanical properties were analyzed by testing the compressive strength and tensile strength of the recycled concrete. Results show that the mechanical properties of recycled concrete, compared with common concrete, can meet the requirements of the project. Water-cement ratio has great influence on compressive strength and tensile strength, replacement ratio has obvious influence on compressive strength but little on tensile.

Abstract: In this paper, the authors study the anti-freeze-thaw performance of a new type of semi-rigid base material named polypropylene fiber reinforced cement-stabilized aggregate, and freeze-thaw mass loss rate, freeze-thaw compressive strength, freeze-thaw splitting strength are used to evaluate the effect of polypropylene fiber on the anti-freeze-thaw performance, and the relationship of polypropylene fiber content, polypropylene fiber length with the anti-freeze-thaw performance are analyzed. The test after 10 freeze-thaw cycle shows that the mix of polypropylene fiber increase the freeze-thaw compressive strength and freeze-thaw splitting strength, and decrease the mass loss rate greatly. At the same time, the paper also determine the reasonable fiber content and fiber length, under this mix proportion, the mass loss rate reduce by 80%, the freeze-thaw compressive strength increase more than 12.1% and freeze-thaw splitting strength increase more than 13.4%. This research has laid an important foundation for the follow-up research and practice.