Abstract

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.

Highlights

  • 1115 : 150 : 50 : 3.4, as tabulated out in Table 2. e designed concrete strength grade is C40. e rubber particles with a particle size of 3 ∼ 6 mm were used to replace 10% medium sand in the concrete. e concrete production process is shown in Figure 2; firstly, the rubber, gravel, sand, fly ash, and cement were mixed and stirred for 60 seconds; the mixture should be removed from the mold and put into the curing box (SHBY-90B) at a temperature of 20°C and a humidity of 95% for 28 days

  • After 60 freeze-thaw cycles, the Crumb Rubber Concrete (CRC) surface began to spall off, and the surface became rough, while the edges and corners became unclear and the surface was uneven after 150 freeze-thaw cycles

  • It can be found that the CRC compressive strength decreased with the number of freeze-thaw cycles and exhibited an obvious downward trend

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Summary

The Sample Preparation and Test Scheme

Rubber particles are produced by crushing waste rubber tires. E test specimens were made by mixing the cement, sand, stone, water, fly ash, and water reducing agent following the benchmark ratio of 310 : 791 :. E concrete production process is shown in Figure 2; firstly, the rubber, gravel, sand, fly ash, and cement were mixed and stirred for 60 seconds; the mixture should be removed from the mold and put into the curing box (SHBY-90B) at a temperature of 20°C and a humidity of 95% for 28 days 1115 : 150 : 50 : 3.4, as tabulated out in Table 2. e designed concrete strength grade is C40. e rubber particles with a particle size of 3 ∼ 6 mm were used to replace 10% medium sand in the concrete. e concrete production process is shown in Figure 2; firstly, the rubber, gravel, sand, fly ash, and cement were mixed and stirred for 60 seconds; the mixture should be removed from the mold and put into the curing box (SHBY-90B) at a temperature of 20°C and a humidity of 95% for 28 days

Test Scheme
Test Results and Analysis
Creep Damage Model of CRC under FreezeThaw Conditions
Conclusions
Full Text
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