scholarly journals Influence of Crack on Concrete Damage in Salt-Freezing Environment

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Guangyan Liu ◽  
Song Mu ◽  
Jingshun Cai ◽  
Deqing Xie ◽  
Ying Zhou ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Mass Loss ◽  
Crack Width ◽  
Mass Loss Rate ◽  
Development Trend ◽  
Initial Crack ◽  
Dynamic Elastic Modulus ◽  
Damage Development ◽  
Concrete Damage ◽  
Freezing Cycle

The damage development trend of concrete with cracks in salt-freezing environment is systematically studied. The cracks are also tested in intact concrete for comparison, and crack characterization is introduced. The mass loss, the relative dynamic elastic modulus, and the change of crack width are analyzed. Results show that the crack width increases as the salt-freezing cycle progresses. Following the development trend of the cracks, concrete cracks can be divided into three categories: 0–40, 40–100, and 100–150 μm. The mass loss increases significantly, and the change of relative dynamic elastic modulus decreases in concrete with an initial crack compared with the intact concrete. When the crack width is 80 μm, a maximum mass loss rate of 0.19% and a minimum relative dynamic elastic modulus of 75.81% can be obtained. These test results prove that crack and freeze-thaw coupling can influence each other and accelerate the failure of concrete. Overall, this study can serve as a basis for the durability design and life improvement of concrete structures.

Microstructure and life prediction model of steel slag concrete under freezing-thawing environment

2021 ◽  
Vol 10 (1) ◽  
pp. 1776-1788
Author(s):  
Yang Wen ◽  
Hui Sun ◽  
Shuaidong Hu ◽  
Guangmao Xu ◽  
Xiazhi Wu ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Mass Loss ◽  
Frost Resistance ◽  
Mass Loss Rate ◽  
Steel Slag ◽  
Quadratic Function ◽  
Northern China ◽  
Calculation Model ◽  
Dynamic Elastic Modulus ◽  
Resistance Durability

Abstract The goals of this paper are to study the frost resistance of steel slag concrete (SSC), research the damage mechanisms, and predict the service life of SSC in cold regions. First, the stability of steel slag (SS) was tested, and then SS samples with different treatment dosages were used as aggregates to replace natural aggregates of equal volumes in the preparation of C40 concrete. The microstructures of concrete and micro properties of cement hydration products were investigated in nanospace in this research. In addition, rapid frost resistance durability tests were carried out under laboratory conditions. The results revealed that the ordinary concrete (OC) exhibited a more serious damage phenomenon, and the mass loss and relative dynamic elastic modulus of OC were changed by 5.27 and 62.30%, respectively. However, with increases in the SS content, the losses in mass were lowered. Furthermore, the relative dynamic elastic modulus decreased less, and the frost resistance of the specimens was stronger. The range of mass loss rate was between 2.233 and 3.024%, and the relative dynamic elastic modulus range was between 74.92 and 91.09%. A quadratic function with a good fitting degree was selected to establish a freezing-thawing damage calculation model by taking the relative dynamic elastic modulus as the variable. Then, the freezing-thawing durability lifespan of concrete in the colder regions of northern China was successfully predicted by using the damage calculation model. The results of SSC20–60 showed the better frost resistance durability when the content of SS sand was 20% and the dosage of SS stone was 60%. Its frost resistance lifespan was more than twice that of OC, which demonstrated that SS as an aggregate could effectively improve the frost resistance lifespan of concrete to a certain extent.

Experimental Study on Frost Resistance Durability and Service Life Prediction of Normal Cement Concrete

2011 ◽  
Vol 368-373 ◽  
pp. 2425-2429 ◽  
Author(s):  
Shi Zhu Lin ◽  
Hui Min Li ◽  
Hong Yan Zhang
Keyword(s):  
Elastic Modulus ◽  
Mass Loss ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Northern China ◽  
Standard Test ◽  
Dynamic Elastic Modulus ◽  
Operation Conditions ◽  
Thawing Process ◽  
Actual Operation

The existing concrete structures, especially hydraulic dams, in the cold areas of northern China have suffered from freeze-thaw damages to varying degrees in the small part or the vast areas of the projects. This paper will work out the performance deterioration index with the relative dynamic elastic modulus and the mass loss rate of the concrete. The test shows that there is a linear relationship between the concrete's relative dynamic elastic modulus and the increasing number of freezing-thawing cycles; the mass loss rate, however, varies with the water-cement ratio and displays different tendency of changes in the initial phase of the cycle, but the mass is decreased in the later phase. Besides, combining with the application, the writer will simulate the concrete's freezing-thawing process under actual operation conditions with the standard test data, in order to offer the presumption model of freezing-thawing durability and predict the residual freezing-thawing life of the concrete, thus providing theoretical basis for the structure's maintenance, repair, and dismantlement.

Experimental Study on Frost Resistance Properties of Pumice Mixed Aggregate Concrete

2012 ◽  
Vol 476-478 ◽  
pp. 1661-1664
Author(s):  
Jun Fang Huo ◽  
Jian Jun Chu ◽  
Hui Yang
Keyword(s):  
Elastic Modulus ◽  
Mass Loss ◽  
Frost Resistance ◽  
Loss Rate ◽  
Mass Loss Rate ◽  
Strength Loss ◽  
Dynamic Elastic Modulus ◽  
Aggregate Concrete ◽  
Freeze Thaw ◽  
Thaw Cycle

Different amount of pumice were used to replace gravel to make mixed aggregate concrete, the fast freeze-thaw cycle test were conducted and the influence of pumice rate substitution to the frost resistance properties of concrete were studied.The mass loss rate, strength loss and relative dynamic elastic modulus were regarded as the evaluation index of frost resistance properties of concrete. Results showed that the mass loss rate and strength loss rate gradually decreased and the relative dynamic elastic modulus gradually increased with the increase of pumice rate, the mass loss rate, strength loss rate and the relative dynamic elastic modulus gradually decreased with the increase of freeze-thaw cycles. Polypropylene fibers could reduce the strength loss rate, improved the relative dynamic elastic modulus, but had little effect to improve the mass loss. Through the frost resistance, the frost resistance of concrete improved with the increase of pumice content, at the same time, polypropylene fiber also could improve the frost resistance of concrete.

scholarly journals Use of Silica Fume and GGBS to Improve Frost Resistance of ECC with High-Volume Fly Ash

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Yushi Liu ◽  
Xiaoming Zhou ◽  
Chengbo Lv ◽  
Yingzi Yang ◽  
Tianan Liu
Keyword(s):  
Elastic Modulus ◽  
Sodium Chloride ◽  
Mass Loss ◽  
Frost Resistance ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Tap Water ◽  
High Volume ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw

Fly ash (FA) has been an important ingredient for engineered cementitious composite (ECC) with excellent tensile strain capacity and multiple cracking. Unfortunately, the frost resistance of ECC with high-volume FA has always been a problem. This paper discusses the influence of silica fume (SF) and ground-granulated blast-furnace slag (GGBS) on the frost resistance of ECC with high volume of FA. Four ECC mixtures, ECC (50% FA), ECC (70% FA), ECC (30% FA + 40% SL), and ECC (65% FA + 5% SF), are evaluated by freezing-thawing cycles up to 200 cycles in tap water and sodium chloride solution. The result shows the relative dynamic elastic modulus and mass loss of ECC in sodium chloride solution by freeze-thaw cycles are larger than those in tap water by freeze-thaw cycles. Moreover, the relative dynamic elastic modulus and mass loss of ECC by freeze-thaw cycles increase with FA content increasing. However, the ECC (30% FA + 40% SL) shows a lower relative dynamic elastic modulus and mass loss, but its deflection upon four-point bending test is relatively smaller before and after freeze-thaw cycles. By contrast, the ECC (65% FA + 5% SF) exhibits a significant deflection increase with higher first cracking load, and the toughness increases sharply after freeze-thaw cycles, meaning ECC has good toughness property.

Comparing Tests on the Durability of Concrete after Long-Term Immersion in Different Salt Solution

2014 ◽  
Vol 501-504 ◽  
pp. 1087-1091 ◽  
Author(s):  
Xiao Ping Su ◽  
Li Zhang
Keyword(s):  
Elastic Modulus ◽  
Salt Solution ◽  
Saline Soil ◽  
Salt Water ◽  
Dynamic Elastic Modulus ◽  
Salt Crystallization ◽  
Soluble Salts ◽  
Concrete Damage ◽  
Damage Law

The western region of Jilin province is one of the areas with the most serious saline soil, which is the type of inland soda salt. In order to study the damage law of concrete under the condition of long-term erosion by the soluble salts in saline soil or groundwater or saturated salt water, three groups of salt solution, Na2SO4, NaCl, NaHCO3 solution, were made according to the content of soluble salts in saline soil of Daan city in spring, and water was as a comparison. The comparing tests of long-term immersion were conducted on the normal concrete specimens with the size of 40mm×40mm×160mm. The results show that there is little change on the appearance, mass and dynamic elastic modulus of concrete soaked in water. But for the concrete soaked in salt solution, the loss rate of mass changes from reduction to growth, the relative dynamic elastic modulus of concrete grows at first and declines later. Through analysis of electron microscope scanning, energy spectrum and chemical composition of concrete samples, concrete damage caused by salts includes chemical erosion and salt crystallization damage. Na2SO4 mainly influences the dynamic elastic modulus of concrete, NaCl mainly influences the mass of concrete due to its strong penetration, while NaHCO3, ranking between the two salts above, largely influences not only the mass of concrete, but also the dynamic elastic modulus of concrete.

scholarly journals Experimental Study on Freeze-Thaw Effects on Creep Characteristics of Rubber Concrete

2022 ◽  
Vol 2022 ◽  
pp. 1-14
Author(s):  
Qi Li ◽  
Fei Xu ◽  
Hemin Zheng ◽  
Junhao Shi ◽  
Jianyu Zhang
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Stress Level ◽  
Creep Behavior ◽  
Mass Loss Rate ◽  
Crumb Rubber ◽  
Dynamic Elastic Modulus ◽  
Freeze Thaw ◽  
Stress Levels ◽  
Rubber Concrete

Crumb Rubber Concrete (CRC) can exhibit high freeze-thaw resistance, but its long-term creep behavior under various freeze-thaw conditions remains unclear, which is essential for the safety of pavement engineering in the severe cold zone. In this study, the freeze-thaw effects on the creep behavior of CRC under different stress levels were systematically analyzed by testing the compressive strength, the uniaxial creep under different stress levels, and the dynamic elastic modulus. To simulate real conditions of the road environment in the cold area, the lowest temperature of −20°C, six freeze-thaw cycles of 0, 30, 60, 90, 120, and 150, and seven different stress levels of 0.4, 0.5, 0.6, 0.7, 0.8, and 0.9 of the compressive strength were employed in this study. The test results showed that the mass loss rate was 6%–11.2% and the compressive strength decreased by 6.51%–47% after 30–150 freeze-thaw cycles. When the stress level reached its critical value, the relative dynamic elastic modulus decreased with the number of freeze-thaw cycles. After 150 freeze-thaw cycles, failure did not appear when the stress level was lower than 50%, above which the creep failure was determined by the stress level and the number of the freeze-thaw cycles. Meanwhile, it was found that the cracking and interfacial debonding between the matrix and the crumb rubber particle were the main reasons for the degradation of CRC creep performance. Finally, a Weibull distribution-based empirical creep damage model was established to predict the failure of CRC, which can enhance its application to related engineering.

scholarly journals Experimental Investigation on the Freeze–Thaw Resistance of Steel Fibers Reinforced Rubber Concrete

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1260
Author(s):  
Tao Luo ◽  
Chi Zhang ◽  
Chaowei Sun ◽  
Xinchao Zheng ◽  
Yanjun Ji ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Elastic Modulus ◽  
Mass Loss ◽  
Loss Rate ◽  
Bending Strength ◽  
Mass Loss Rate ◽  
Steel Fibers ◽  
Freeze Thaw ◽  
Four Point Bending ◽  
Rubber Concrete

The reuse of rubber in concrete results in two major opposing effects: an enhancement in durability and a reduction in mechanical strength. In order to strengthen the mechanical properties of rubber concrete, steel fibers were added in this research. The compressive strength, the four-point bending strength, the mass loss rate, and the relative dynamic elastic modulus of steel fiber reinforced rubber concrete, subjected to cyclic freezing and thawing, were tested. The effects of the content of steel fibers on the freeze–thaw resistance are discussed. The microstructure damage was captured and analyzed by Industrial Computed Tomography (ICT) scanning. Results show that the addition of 2.0% steel fibers can increase the compressive strength of rubber concrete by 26.6% if there is no freeze–thaw effect, but the strengthening effect disappears when subjected to cyclic freeze–thaw. The enhancement of steel fibers on the four-point bending strength is effective under cyclic freeze–thaw. The effect of steel fibers is positive on the mass loss rate but negative on the relative dynamic elastic modulus.

Experimental Study on Freeze-Thaw Resistance of Concrete with Proto-Machine-Made Sand

2011 ◽  
Vol 71-78 ◽  
pp. 4361-4364 ◽  
Author(s):  
Xiao Yan Zhang ◽  
Xin Xin Ding ◽  
Shun Bo Zhao ◽  
Zhan Fang Ge
Keyword(s):  
Experimental Study ◽  
Elastic Modulus ◽  
Mass Loss ◽  
Source Rock ◽  
Crushed Stone ◽  
Dynamic Elastic Modulus ◽  
Cycle Times ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

Experiments were conducted to study the effects of source rock state and stone powder on freeze-thaw resistance of concrete with proto-machine-made sand, the strength grade of concrete was C50, the source rock states were gravel and crushed stone, the contents of stone powder in sand were 5%, 9% and 13% respectively. The values of relative dynamic elastic modulus and mass of concrete at different freeze-thaw cycle times were measured, the reduction of relative dynamic elastic modulus and mass loss were calculated to evaluate the freeze-thaw resistance of concrete. The results show that freeze-thaw resistances are controlled by the reduction of relative dynamic elastic modulus of concrete, which are good of concrete with proto-machine-made sand of gravel and crushed stone, and increases with the increasing content of stone powder in sand made of gravel. The reasons leading to difference of freeze-thaw resistance of concrete with sand made of gravel and crushed stone are discussed.

Evaluating the Air-Entraining Concrete Performance Decay Rule under Long-Term Salts Corrosion Using MATLAB Software

2014 ◽  
Vol 1015 ◽  
pp. 124-128
Author(s):  
Xiao Ping Su ◽  
Hao Yue Sun
Keyword(s):  
Elastic Modulus ◽  
Linear Regression ◽  
Evaluation Model ◽  
Evaluation Index ◽  
Dynamic Elastic Modulus ◽  
Concrete Durability ◽  
Durability Test ◽  
Matlab Software ◽  
Concrete Damage

In the concrete salt-soaking durability test, the dynamic elastic modulus of concrete is more sensitive to the concrete damage than the mass, and can reflect the concrete durability better. In this paper,the relative dynamic elastic modulus of concrete is used as the evaluation index of concrete durability. Its attenuation law is made the multiple linear regression by using MATLAB software. The evaluation model and its applicable conditions of the relative dynamic elastic modulus of air-entraining concrete under the action of the long-term salt immersion are obtained, which can be used to evaluate and precast the durable degree of air-entraining concrete in the salt environment.

Comparison and Selection of the Durability Evaluating Parameters of Concrete in Saline Soil Region

2014 ◽  
Vol 919-921 ◽  
pp. 1751-1754 ◽  
Author(s):  
Li Zhang ◽  
Xiao Ping Su
Keyword(s):  
Elastic Modulus ◽  
Saline Soil ◽  
Degradation Process ◽  
Dynamic Elastic Modulus ◽  
Failure Behavior ◽  
Concrete Durability ◽  
Salt Corrosion ◽  
Concrete Damage ◽  
Main Index ◽  
Durability Of Concrete

The mal-condition of environment directly affects the durability of concrete, and which has become a widespread problem under the complicated environment conditions. Domestic and overseas scholars have carried out many researches on the durability of concreteunder different environmental conditions. The mass and the dynamic elastic modulus loss are focused as two major criteria in the evaluation of concrete damage. The article further gives researches on the durability of concrete in the saline soil environment in the west region of Jilin province. The concrete durability tests are conducted under the actions of salt soaking, salt corrosion and freezing-thawing cycles, and salt corrosion and dry-wet cycles. Comparing the test results in the same coordinate system, it is concluded that the dynamic elastic modulus of concrete can reflect the degradation process of concrete performance more accurately and intuitively, and forecast the failure behavior of concrete under the action of various environmental factors timely and effectively. Therefore it can be used as the main index for no damage detection, while the mass loss can be acted as the auxiliary detection index during the concrete durability tests.

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