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.

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.

Experimental Study on Strength Characteristics Comparison of Tamped and Poured Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 492-497
Author(s):  
Xi Yuan Liu ◽  
Yan Feng Li ◽  
Zhao Xia Chen ◽  
Ling Wang
Keyword(s):  
Compressive Strength ◽  
Influence Factors ◽  
Strength Characteristics ◽  
Test Results ◽  
Optimum Parameters ◽  
Foundation Treatment ◽  
Mix Proportion ◽  
Curing Condition ◽  
The Difference ◽  
The Cost

Piles formed by tamped concrete are a kind of technology in foundation treatment. In order to study the difference of strength characteristics between tamped and ordinary poured concrete, optimum parameters of mix proportion on tamped concrete are obtained by heavy compaction test in laboratory, then unconfined compressive strength tests are accomplished on the basis of optimum parameters of mix proportion. Influence factors of strength characteristics of tamped concrete are studied, such as cement-aggregate ratio, curing age, curing condition and so on. Finally, strength characteristics of tamped and ordinary poured concrete are compared. The test results indicate that the tamped concrete is hardened quickly and early-strength. In standard, water and saturated soil curing condition, compressive strength all grows sufficiency, thus tamped concrete can be used in ground and underground environment. At the same time, a higher strength can be obtained by smaller cement content, and the cost of tamped concrete can be reduced effectively.

Experimental Study on Frost Resistance of the Shale Ceramsite Concrete

2011 ◽  
Vol 117-119 ◽  
pp. 1754-1758 ◽  
Author(s):  
Wei Jun Yang ◽  
Yong Da Yang ◽  
Yi Yang
Keyword(s):  
Experimental Study ◽  
Frost Resistance ◽  
Absorption Characteristic ◽  
Cement Ratio ◽  
Freeze Thaw ◽  
Air Content ◽  
Mix Proportion ◽  
Study Results ◽  
Wetting Time ◽  
Structure Water

In this presented work, by freeze-thaw test for three groups of shale ceramsite concrete with different mix proportion, the experimental results show: the shale ceramsite concrete has preferable frost resistance property. After 100 times freeze-thaw cycles, its loss in weight and strength is very small; the frost resistance increases as ceramsite pre-wetting time is raised, and with the increasing of the water cement ratio, the frost resistance declines. The statement that ceramsite pre-wetting treatment is detrimental to frost resistance still deserves discussion, as it depends on the pore structure, water absorption characteristic and concrete air content of ceramsite itself. Meanwhile, freeze-thaw mechanism of the shale ceramsite concrete was analyzed in this paper. The study results provide some reference for other studies.

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 Frost Resistance Test Research on Hybrid Fiber Concrete Based on Range Analysis

2015 ◽  
Vol 9 (1) ◽  
pp. 292-297 ◽  
Author(s):  
Liu Faming ◽  
Zhao Lisha ◽  
Ma Jie
Keyword(s):  
Compressive Strength ◽  
Frost Resistance ◽  
Loss Rate ◽  
Steel Fiber ◽  
Polypropylene Fiber ◽  
Strength Loss ◽  
Hybrid Fiber ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Fiber Concrete

The research of single doped fiber concrete is relatively mature. But the research about different varieties and different geometry shape of hybrid fiber concrete was very poor. Across the research in theory, hybrid fiber concrete can improve the balance of fiber three-dimensional distribution and coordinating role of aggregate and fiber, improve the efficiency of toughening crack resistance. In this paper, through the orthogonal experiment design method for hybrid fiber reinforced concrete, the mass and compressive strength loss rate after 50 times, 75 times, 100 times freeze-thaw cycle had been studied. Use range analysis quantified the influence level of various factors on the mechanical properties. It was analyzed the hybrid fiber influence on improving the efficiency of toughening crack resistance and frost resistance. It is concluded that adding the fiber can enhance the performance of concrete frost resistance. Long steel fiber have great influence on compressive strength loss rate of hybrid fiber concrete, such as the compressive strength loss rate was reached 65.47% after 75 times freeze-thaw cycle. Short steel fiber have certain influence on mass loss of concrete which were after less freeze-thaw cycles. The influence of polypropylene fiber on concrete frost resistance increases significantly, the effect can reach 36.78% after 50 times of freeze-thaw cycle. The optimal combination of the hybrid fiber concrete ultimately determined was A2B2C3 (simultaneously mixed with 50kg/m3 short steel fiber and long steel fiber as well as 0.9kg/m polypropylene fiber). The addition of steel fiber and polypropylene fiber are both beneficial to increase the internal air content of concrete, strengthening the frost resistance of concrete. However, with the increase of dosage, the internal porosity of concrete is gradually increasing, the density is reduced, and, as a result, the corresponding increase of the compressive strength loss rate is also improved.

An Experimental Study on the Frost Resistance of High Performance Concrete Using Fly-Ash and Agent

2017 ◽  
Vol 904 ◽  
pp. 179-184
Author(s):  
Seung Jo Lee
Keyword(s):  
Experimental Study ◽  
Compressive Strength ◽  
Fly Ash ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
Frost Resistance ◽  
High Performance ◽  
High Performance Concrete ◽  
Strength Increase ◽  
Freeze Thaw

The purpose of this study is to investigate the freeze-thaw resistance, one of the most important durability indicators, of high-performance concrete made of fibers (nylon and polypropylene), AE agent, viscosity agent, and fly ash, an industrial by-product. While FN-1 showed the best freeze-thaw resistance with an about 2.8% relative dynamic modulus of elasticity, PV-2 showed the worst results, with an about 7.4% modulus, in comparison tests with GC. Most of the test samples showed better compressive strength than GC. Especially, N-1 showed the greatest compressive strength increase of 8%. Also, the test samples mixed with FA and PP showed a 2-4% compressive strength increase effect.

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.

scholarly journals Influence of the Size and Type of Pores on Brick Resistance to Freeze-Thaw Cycles

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3717
Author(s):  
Ivanka Netinger Grubeša ◽  
Martina Vračević ◽  
Vilma Ducman ◽  
Berislav Marković ◽  
Imre Szenti ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Frost Resistance ◽  
Mercury Porosimetry ◽  
Micro Ct ◽  
Freeze Thaw ◽  
Damage Degree ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Overall Resistance ◽  
Open Versus

This paper estimates the frost resistance of bricks using the ratio of compressive strength before freezing to compressive strength after freezing to describe the damage degree of bricks being exposed to freeze-thaw cycles. In an effort to find the ratio that clearly distinguishes resistant bricks from non-resistant bricks, the authors attempted to establish the correlation between the ratio and Maage factor as a recognized model for assessing brick resistance. To clarify the degree of damage of individual bricks, the pore size distribution has been investigated by means of mercury porosimetry. Additionally, micro computed X-ray tomography (micro-CT) has been employed to define the influence of the type of pores (open or closed) and their connectivity on the frost resistance of bricks. According to the results, it can be concluded that there is a good correlation between the Maage factor and the ratio of pre- to post-freeze-thaw cycle compressive strengths, and that the latter ratio strongly correlates with the percentage of large pores (≥3 mm) in the brick. If such a correlation could be confirmed in a larger sample, then the ratio of pre- to post-freeze-thaw cycle compressive strengths could be used as a new method for assessing brick resistance to freeze-thaw cycles and it would be possible to determine the minimum percentage of large pores required to ensure the overall resistance of brick to freeze-thaw conditions. The complexity of the problem is, however, evidenced by the fact that no clear connection between the type (open versus closed) or connectivity of pores and the frost resistance of bricks could be revealed by micro-CT.

Experimental Research on a New-Type Concrete Antifreeze

2011 ◽  
Vol 148-149 ◽  
pp. 1209-1213
Author(s):  
Bao Min Wang ◽  
Kai Song ◽  
Ni Tu
Keyword(s):  
Compressive Strength ◽  
Loss Rate ◽  
Performance Test ◽  
Setting Time ◽  
Strength Loss ◽  
Freeze Thaw ◽  
Performance Indexes ◽  
Thaw Cycle ◽  
Basic Performance ◽  
Freeze Thaw Cycle

Basic performance test was performed on a newly-developed compound antifreeze and experiment was carried out to study the basic performance, mechanical property and durability of the concrete mixtures containing 0%, 4% and 5% antifreeze. The result shows the antifreeze may be used for the concrete construction at 20°C below zero and it has favorable performance for winter construction. When the amount to be added is 4% and 5%, the ratio of compressive strength of 28 days shall be 105% and 107% respectively; the ratio of compressive strength of 56 days shall be 114% and 112% respectively. In freeze-thaw cycle experiment, 50 times of freeze-thaw strength loss rate is 45.3% and 44.8% of the strength loss rate of the concrete without the antifreeze. The water-reducing ratio of the antifreeze, ratio of bleeding rate, air content, difference in setting time, strength ratio, ratio of shrinkage, permeated height ratio and other performance indexes all satisfy specification requirements.

scholarly journals Effect of Fast Freeze-Thaw Cycles on Mechanical Properties of Ordinary-Air-Entrained Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Huai-shuai Shang ◽  
Wei-qun Cao ◽  
Bin Wang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Life Prediction ◽  
Cold Region ◽  
Mathematical Formula ◽  
Laboratory Environment ◽  
Freeze Thaw ◽  
Cleavage Strength ◽  
Concrete Materials ◽  
Air Entrained Concrete

Freezing-thawing resistance is a very significant characteristic for concrete in severe environment (such as cold region with the lowest temperature below 0°C). In this study, ordinary-air-entrained (O-A-E) concrete was produced in a laboratory environment; the compressive strength, cubic compressive strength of C50, C40, C30, C25, and C20 ordinary-air-entrained concrete, tensile strength, and cleavage strength of C30 ordinary-air-entrained concrete were measured after fast freeze-thaw cycles. The effects of fast freeze-thaw cycles on the mechanical properties (compressive strength and cleavage strength) of ordinary-air-entrained concrete materials are investigated on the basis of the experimental results. And the concise mathematical formula between mechanical behavior and number of fast freeze-thaw cycles was established. The experiment results can be used as a reference in design, maintenance, and life prediction of ordinary-air-entrained concrete structure (such as dam, offshore platform, etc.) in cold regions.

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