scholarly journals Frost resistance of cement-sand and concrete beams during unilateral freezing

2021 ◽  
Vol 2 (1) ◽  
pp. 64-74
Author(s):  
Nepomyach Alexander Nikolaevich ◽  
Vyrovoy Valeriy Nikolaevich ◽  
Chistyakov Artem Aleksaedrovich
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Bending Strength ◽  
Concrete Beams ◽  
Transmission Rate ◽  
Beam Structure ◽  
Freeze Thaw ◽  
Damage Coefficient ◽  
Negative Temperatures

Abstract The work investigates changes in the beam structure under the action of local freezing, which leads to a change of the mechanical properties of the material and, consequently, of the beam structure. Two types of beam samples were used: from cement-sand mortar and from concrete. The work investigates the change in the development of deformations depending on the conditions of freezing of samples. The second accelerated method for assessing frost resistance was chosen according to DSTU B В.2.7-47-96. An accelerated method was chosen for assessing frost resistance at the temperature of -20 ±2 C°. After every five freeze-thaw cycles, the following changes were monitored: mass, water absorption, ultrasound transmission rate, damage coefficient, tensile bending strength, splitting strength, compressive strength, carbonization depth. The results showed that both in concrete and in mortar samples, the compressive strength after freezing was lower by 8% and 15% accordingly. The experimental results obtained confirm the assumptions made that the frost resistance of the material depends on the conditions of exposure of negative temperatures on products and structures and it can be used in a wider range of construction which will push regional development.

scholarly journals Study on the Mechanical Properties and Frost Resistance of Multiple Modified Concrete

2021 ◽  
Author(s):  
Xiaosa Yuan ◽  
Li Zhang ◽  
Xinxiao Chen ◽  
Fang Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Frost Resistance ◽  
Steel Fiber ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Compressive Strength Of Concrete ◽  
Better Than ◽  
Mixed Concrete

Abstract To study the effects of graphene oxide (GO), fly ash, and steel fiber on the mechanical properties and durability of concrete, the mechanical properties, frost resistance, and internal pore structure of modified concrete are investigated by compression tests, freeze–thaw cycle tests, and industrial computed tomography (CT) tests. The test results show that the compressive strength of concrete with GO is better than that of mixed concrete, concrete mixed with only steel fiber, and ordinary concrete. Further, it is strongest at all ages when the GO content is 0.03%; the compressive strength of mixed concrete with 30% of fly ash is generally better than that with 15% and 45% of fly ash. In general, the frost resistance of concrete with only GO is better than that of ordinary concrete. With the increase in fly ash content, the internal porosity of concrete decreases, and its compressive strength increases accordingly; as GO increases, the porosity decreases and then increases, with the lowest porosity and the highest compressive strength of concrete at 0.03% of GO. With an increase in porosity, the mass loss and relative dynamic elastic modulus of concrete increase after 100 freeze–thaw cycles, which indicates that porosity directly affects the frost resistance of concrete.

scholarly journals Effect of Silica Fume and Polyvinyl Alcohol Fiber on Mechanical Properties and Frost Resistance of Concrete

Buildings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 47
Author(s):  
Yan Tan ◽  
Ziling Xu ◽  
Zeli Liu ◽  
Jiuhong Jiang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Silica Fume ◽  
Frost Resistance ◽  
Strength Test ◽  
Freeze Thaw ◽  
Polyvinyl Alcohol Fiber

To improve the mechanical properties and frost resistance of concrete, silica fume, and polyvinyl alcohol fiber compounded in concrete. The mechanical and frost resistance of concrete were comprehensively analyzed and evaluated for strength change, mass loss, and relative dynamic elastic modulus change by compressive strength test, flexural strength test, and rapid freeze-thaw test. The results showed that with the incorporation of silica fume and polyvinyl alcohol fiber, the compressive and flexural strengths of concrete were improved, and the decrease in mass loss rate and relative dynamic elastic modulus of concrete after freeze-thaw cycles were significantly reduced, which indicated that the compounding of silica fume and polyvinyl alcohol fiber improved the frost resistance of concrete. When the content of silica fume was 10% and the volume content of polyvinyl alcohol fiber was 1%, the comprehensive mechanical performance and frost resistance of concrete is the best. The compressive strength increased by 26.6% and flexural strength increased by 29.17% compared to ordinary concrete. Based on the test data, to study the macroscopic damage evolution of concrete compound silica fume and polyvinyl alcohol fiber under repeated freeze-thaw conditions. The Weibull distribution probability model and GM (1, 1) model were established. The average relative errors between the predicted and actual data of the two models are small and very close. It is shown that both models can reflect well the development of concrete damage under a freeze-thaw environment. This provides an important reference value and theoretical basis for the durability evaluation and life prediction of compound silica fume and polyvinyl alcohol fiber concrete in cold regions.

Study on the Mechanical Properties and Frost Resistance of Recycled Concrete Prepared by Village Construction Wastes

2011 ◽  
Vol 418-420 ◽  
pp. 406-410
Author(s):  
Jun Liu ◽  
Yao Li ◽  
Dan Dan Hong ◽  
Yu Liu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Cement Mortar ◽  
Strength Loss ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Concrete Mechanical Properties ◽  
Better Than

Abstract. Recycled aggregate—rural building material wastes pretreated by cement mortar—are applied into concrete with different replacement rates: 0, 25%, 50%, 75%, and 100%. Results from measurements of compressive strength, cleavage tensile strength, mass loss after fast freeze-thaw cycles, and compressive strength loss indicate that a different recycled aggregate replacement rate certainly influences concrete mechanical properties and frost resistance. Recycled aggregate replacement rates less than 75% performs better than common concrete. Data from the 100% replacement rate is worse than that of rates less than 75% but still satisfy the general demands of GB standard on C30 concrete.

Optimization Research of Mix Proportion of Frost Resistance Construction of Concrete Based on the MATLAB Language

2014 ◽  
Vol 584-586 ◽  
pp. 1917-1921
Author(s):  
Jun Jie Zhang ◽  
Rui Hong Shao ◽  
Xiang Yi Meng
Keyword(s):  
Compressive Strength ◽  
Objective Function ◽  
Frost Resistance ◽  
Unit Volume ◽  
Influence Factors ◽  
Multi Objective Optimization ◽  
Cold Region ◽  
Freeze Thaw ◽  
Performance Indexes ◽  
Mix Proportion

Analyze the influence factors of mix proportion affecting concrete freeze-thaw damage. Use the five main performance indexes of the concrete, which are compressive strength, strength of extension, impermeability grade, and frost resistance grade and per unit volume cost concrete, as the objective function of multi-objective optimization equation. Invoke the fgoalattain function in the MATLAB Optimization Toolbox to solve. The optimized parameters of mix proportion of frost resistance construction of unit concrete in cold region are: concrete 1532.6kg, water 910kg, sand 5510.6kg, 5-20mm cobblestone 3747.2kg、20-40mm cobblestone 3658.6kg、40-80mm cobblestone 4733.5kg、80-150mm cobblestone 4738.1kg, and the dosage of water reducing agent is 7.3kg.

Physical Properties of Building Blocks from Hemp Shives Aggregate and Cementitious Binder, Manufactured in the Expanded Clay (Vibro Pressing) Production Line

2017 ◽  
Vol 908 ◽  
pp. 118-122 ◽  
Author(s):  
Giedrius Balčiūnas ◽  
Viktor Kizinievič ◽  
Justinas Gargasas
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Physical Properties ◽  
Production Line ◽  
Scientific Literature ◽  
Building Blocks ◽  
Freeze Thaw ◽  
Cementitious Binder ◽  
Pressing Technology

Scientific literature mostly aims at investigation of composites with fibre hemp shives (FHS) aggregate and lime binder, although, such materials are characterised by pretty low mechanical properties. In order to obtain higher mechanical properties of a composite, it is appropriate to use cementitious binder. This work investigates physical properties of blocks from hemp shives aggregate and cementitious binder, manufactured in the expanded clay production line using vibro pressing technology. Following properties of the blocks are determined: freeze-thaw resistance, compressive strength, thermal conductivity and density. Thermal resistance according to EN ISO 6946 for the block with cavities is calculated as well. It is found that compressive strength of FHS-cement blocks may be up to 3.18 MPa when the density is of ~850 kg/m3 and thermal conductivity up to 0.135 W/(m∙K). It is found as well that the decrease of compressive strength is 8.7% after 25 freeze-thaw cycles.

scholarly journals The Effect of Borax Solution as Preservative to the Mechanical Properties of Bamboo

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
M.A.P Handana ◽  
◽  
Besman Surbakti ◽  
Rahmi Karolina ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Bending Strength ◽  
Environmentally Friendly ◽  
Preservative Solution ◽  
Borax Solution ◽  
Preservative Solutions

The use of borax solution as a preservative in wood and bamboo materials is well known in the community. A borax solution is an environmentally friendly liquid that can dissolve in water, so it is suitable to be used as a preservative within cold or hot soaking techniques. The ability of borax to resist insects and fungus attacks on bamboo has been proven, but the effect of the solution on the strength of bamboo must also be investigated. This study conducts to investigate the effects of borax and its additives as preservative solutions to the mechanical properties of bamboos. The bamboos preservations were conducted by cold conditions of immersion, while the mechanical properties were performed to understand the effects of preservatives. The result of this study indicated that 30% to 50% borax in the preservative solution is sufficient to provide significant increase in strength for compressive strength, tensile strength, and bending strength of bamboo specimen. From this study, the use of borax solution in preserving the bamboos materials improved the quality of bamboos based on its mechanical properties.

Mechanical properties and freeze-thaw resistances of bronze-concrete composites

2021 ◽  
Vol 12 (2) ◽  
pp. 39
Author(s):  
Tuba Bahtli ◽  
Nesibe Sevde Ozbay
Keyword(s):  
Mechanical Properties ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Test Methods ◽  
Pulse Velocity ◽  
Plastic Energy ◽  
Freeze Thaw ◽  
Schmidt Rebound Hammer

Studies in the literature show that the physical and mechanical properties of concrete could be improved by the incorporation of different kinds of industrial waste, including waste tire rubber and tire steel. Recycling of waste is important for economic gain and to curb environmental problems. In this study, finely ground CuAl10Ni bronze is used to improve the physical and mechanical properties, and freeze-thaw resistances of C30 concrete. The density, cold crushing strength, 3-point bending strength, elastic modulus, toughness, and freeze-thaw resistances of concrete are determined. In addition, the Schmidt Rebound Hammer (SRH) and the ultrasonic pulse velocity (UPV) tests, which are non-destructive test methods, are applied. SEM/EDX analyses are also carried out. It is noted that a more compacted structure of concrete is achieved with the addition of bronze sawdust. Then higher density and strength values are obtained for concretes that are produced by bronze addition. In addition, concretes including bronze sawdust generally show higher toughness due to high plastic energy capacities than pure concrete.

scholarly journals Influence of Restrained Condition on Mechanical Properties, Frost Resistance, and Carbonation Resistance of Expansive Concrete

Materials ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2136
Author(s):  
Nguyen Duc Van ◽  
Emika Kuroiwa ◽  
Jihoon Kim ◽  
Hyeonggil Choi ◽  
Yukio Hama
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Frost Resistance ◽  
Total Porosity ◽  
Length Change ◽  
Ratio Test ◽  
Expansive Concrete ◽  
Restrained Condition ◽  
Carbonation Resistance ◽  
Compressive Strength Test

This paper presents the results of an experimental investigation of the effect of the restrained condition on the mechanical properties, frost resistance, and carbonation resistance of expansive concrete with different water–binder ratios. In this study, length change ratio test, expansion strain test, compressive strength test, mercury intrusion porosimetry test, underwater weighing test, freezing–thawing test, and accelerated carbonation test were performed to evaluate the mechanical properties, pore size distribution, total porosity, and durability of expansive concrete under both restrained and unrestrained conditions. The test results indicate that the length change ratio and expansion strain of the expansive concrete were controlled by the restrained condition. The compressive strength of expansive concrete was enhanced by the triaxial restraining when the amount of expansive additive was 40 kg/m3 of concrete. Two hypotheses were described to explain the change of pore structure change expansive mortar. The results also indicate that the carbonation resistance and frost resistance were improved by the uniaxial restrained condition. Furthermore, the effect of the restrained condition must be considered to evaluate not only the experimental results of the expansive concrete with a high EX replacement level but also the expansive concrete combining other cement replacement materials.

Autoclaved Brick from Steel Slag and Silicon Tailings

2014 ◽  
Vol 878 ◽  
pp. 194-198 ◽  
Author(s):  
Peng Guan Li ◽  
Feng Qing Zhao
Keyword(s):  
Compressive Strength ◽  
Total Mass ◽  
Bending Strength ◽  
Steel Slag ◽  
Drying Shrinkage ◽  
Load Bearing ◽  
Volume Stability ◽  
Freeze Thaw

The load-bearing brick is made from steel slag and silicon tailings by pressing and autoclaving process. Because of the volume stability, steel slag was ground to above 320 m2/kg and wet cured in 50-60°C at 12-24 hours in the present of additives, before pressure forming and autoclaving process. Tailings account for 63% of the total mass of the brick, while steel slag 30 %. The compressive strength of the brick was up to 13.1MPa, bending strength 3.2MPa, and with low drying shrinkage and good freeze-thaw resistance. The application conditions were discussed.

scholarly journals Influence of Mullite Wool Waste on the Properties of Ceramics

1970 ◽  
Vol 17 (1) ◽  
pp. 80-85
Author(s):  
Jurgita MALAIŠKIENĖ
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Water Absorption ◽  
Firing Temperature ◽  
Frost Resistance ◽  
Effective Porosity ◽  
Flow Reserve ◽  
Optimum Quantity ◽  
Ceramic Samples ◽  
Porous Volume

In the paper, the influence of mullite wool waste additive on the properties of building ceramics is analysed. For that purpose four formation masses were prepared, dried and fired at the analogous regimes (maximum firing temperature 1080 °C). The fired samples were used to determine the structural and physical-mechanical properties. The values of these parameters are analysed: water absorption, total and effective porosity, rate of capillary mass flow, reserve of porous volume, compressive strength, density and estimated exploitation frost resistance. It has been determined that mullite wool waste can be applied to the production of building ceramics and the optimum quantity of waste in a formation mass is 10 % according to weight. Water absorption of those ceramic samples was less than 4 %, compressive strength was 28.6 MPa, density - 2033 kg/m3, forecasted resistance to frost about 400 cycles.http://dx.doi.org/10.5755/j01.ms.17.1.255

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