Structural effects of freeze–thaw depth on shear strength of an existing RC bridge pier

Author(s):  
T. Kanazawa ◽  
Y. Ushiwatari ◽  
M. Sakoh ◽  
R. Kawase
Author(s):  
Takeru KANAZAWA ◽  
Takuro NAKAMURA ◽  
Junichi SAKAGUCHI ◽  
Kazuhiro KAWAGUCHI

2018 ◽  
Vol 55 (8) ◽  
pp. 1059-1066 ◽  
Author(s):  
G. Ward Wilson ◽  
Louis K. Kabwe ◽  
Nicholas A. Beier ◽  
J. Don Scott

Regulatory policy and regulations in Alberta require oil sands companies to reduce their production and storage of fluid fine tailings by creating deposits that can be reclaimed in a timely manner. To meet the regulatory requirements, some companies are adding flocculants to the fluid fine tailings and then using thickeners, inline flocculation or centrifuges to increase the solids content. Freeze–thaw and drying processes are then used to further dewater the tailings. The effects of flocculating, thickening, and freeze–thaw treatments were investigated by performing large-strain consolidation and shear strength tests on these treated fluid fine tailings. The consolidation and shear strength results were then compared with those of untreated fluid fine tailings. All of the treatments increased the hydraulic conductivity of the fluid fine tailings to some degree, but had little to no effect on the compressibility and shear strength. The effects of the treatment processes are discussed and evaluated.


Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1251
Author(s):  
Tao Luo ◽  
Chi Zhang ◽  
Xiangtian Xu ◽  
Yanjun Shen ◽  
Hailiang Jia ◽  
...  

Frost damage of concrete has significant effects on the safety and durability of concrete structures in cold regions, and the concrete structures after repair and reinforcement are still threatened by cyclic freezing and thawing. In this study, the new-to-old concrete interface was reinforced by steel bar. The shear strength of the new-to-old concrete interface was tested after the new-to-old combination was subjected to cyclic freeze–thaw. The effects of the diameter of the steel bar, the compressive strength of new concrete, the number of freeze–thaw cycles and the freezing temperatures on the shear properties of new-to-old concrete interface were studied. The results showed that, in a certain range, the shear strength of the interface was proportional to the diameter of the steel bar and the strength of the new concrete. Meanwhile, the shear strength of the reinforced interface decreased with the decreasing of the freezing temperature and the increasing of the number of freeze–thaw cycles.


1988 ◽  
Vol 68 (4) ◽  
pp. 763-774 ◽  
Author(s):  
LINNELL M. EDWARDS

Soil physical characteristics were examined at depth intervals of 0–15 and 15–30 cm over three slope positions (top-, mid-, and bottom-slope) for three cropping sequences (hay-barley, cereals-barley, and potato-barley). Hydraulic conductivity was a significant (P ≤ 0.05) 40–50% greater at top-slope than mid- or bottom-slope, and aggregate stability percentage was a significant 6–7% greater at bottom-slope than mid- or top-slope when the soil aggregates were pretreated by freezing and thawing (freeze/thaw). Under the potato-barley sequence shear strength, penetration resistance and bulk density were significantly greater than any other sequence by up to 29, 21 and 15%, respectively; while hydraulic conductivity and maximum penetration depth were, respectively, up to 65 and 28% lower than any other sequences. Under hay-barley, hydraulic conductivity and aggregate stability (freeze/thaw) were, respectively, up to a significant 82 and 10% greater than any other sequence. There was, therefore, significantly more compaction under potato-barley and more soil physical enhancement under hay-barley than other respective sequences. Disease severity was up to 55% greater at bottom-slope than at mid-slope or top-slope for Birka barley, which also showed a significant linear decrease (r2 = 0.89) in yield with increasing shear strength. Yield of Perth barley showed a significant linear increase with increasing soil depth (r2 = 0.92) and clay-silt content (r2 = 0.78). Key words: Aggregate stability (freeze/thaw), crop rotation, penetration resistance, shear strength, barley, potatoes, hay


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yanlong Li ◽  
Zili Wang ◽  
Yang Luo

Shear strength of shallow expansive soil varies along with the depth under the freeze-thaw effect. This work investigates shear strength characteristics of shallow expansive soil by simulating the actual freeze boundary conditions of seasonal frozen areas with water supplement. An integrated approach incorporating the freeze-thaw test and direct shear test was adopted. Firstly, unidirectional freezing tests for expansive soil columns under three different freezing temperature gradients were carried out. Secondly, direct shear tests under low vertical stress were performed on the standard samples, which were prepared by using cutting rings cut the thawed expansive soil columns into nine segments along with the depth. Temperature, water content, and dry density at different depths were also investigated after the freeze-thaw process. The test results showed that, after the freeze-thaw process, the shear strength of expansive soil columns showed significant differences along with the depth and highly correlated with water content, specifically the higher water content and the lower shear strength. The minimum shear strength in the expansive soil columns occurred at the soil layer below the frozen and unfrozen zones interface. The expansive soil column’s shear strength changed most under the moderate freezing temperature gradient corresponding to the most considerable shear strength reduction. Moreover, the significant decrease in cohesion was the main reason for the shear strength reduction of expansive soil after the freeze-thaw process. These results indicate significant depth variability in shear strength of expansive soil under the freeze-thaw effect.


Author(s):  
Xin Jing ◽  
Zizhi Cui ◽  
ShuIng Doh ◽  
Li Ma ◽  
Lu Wei ◽  
...  

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