scholarly journals Effect evaluation of freeze-thaw on resilient modulus of unsaturated granular base course material in pavement

2019 ◽  
Vol 21 ◽  
pp. 100284 ◽  
Author(s):  
Tatsuya Ishikawa ◽  
Tianshu Lin ◽  
Shinichiro Kawabata ◽  
Shuichi Kameyama ◽  
Tetsuya Tokoro
Author(s):  
Tatsuya ISHIKAWA ◽  
Yuan ZHANG ◽  
Shinichiro KAWABATA ◽  
Shuichi KAMEYAMA ◽  
Tetsuya TOKORO

Author(s):  
Shinichiro KAWABATA ◽  
Tatsuya ISHIKAWA ◽  
Takumi MURAYAMA ◽  
Shuichi KAMEYAMA

Author(s):  
Khaled Sobhan ◽  
Raymond J. Krizek

A stabilized fiber-reinforced base course material composed largely of recycled concrete aggregate with small amounts of portland cement and fly ash was subjected to repeated flexural loading to evaluate its resilient properties and progressive accumulation of fatigue damage. Cyclic load-deformation data were recorded continuously during the entire fatigue life until fracture to determine ( a) the magnitude and variation of cumulative plastic strain and dynamic elastic modulus as a function of the number of loading cycles, ( b) a range for the resilient modulus, and ( c) the effect of fiber inclusions on the dynamic material properties and rate of damage accumulation. The extent of fatigue damage was calculated as a fatigue damage index, which is based on the cumulative energy dissipated (absorbed) during cyclic loading. All beam specimens used in this experimental program contained (by weight) 4 percent cement, 4 percent fly ash, and 92 percent recycled aggregate; the fiber-reinforced specimens contained an additional 4 percent (by weight) hooked-end steel fibers. Results show that the resilient modulus in flexure varies between about 2.75 GPa (400,000 lbf/in2.) and 10.4 GPa (1.5 million lbf/in.2) and the degradation of the dynamic elastic modulus does not exceed 25 percent of the initial modulus. Miner’s Rule of linear summation of damage is applicable to unreinforced material but not to fiber-reinforced material. In general, a modest amount of reinforcing fibers was very effective in retarding the rate of fatigue damage accumulation in this lean cementitious composite.


2021 ◽  
Vol 9 (2) ◽  
pp. 143
Author(s):  
Na Li ◽  
Yalan Zhu ◽  
Fang Zhang ◽  
Sin Mei Lim ◽  
Wangyi Wu ◽  
...  

This study aimed to investigate the feasibility of using polypropylene fiber-cement-stabilized coastal clay as base-course material or foundation material for city sustainable development by assessing its mechanical performance. The influence of the number of freeze–thaw cycles and curing ages on the mechanical properties of ordinary cemented clay (OCC) and polypropylene fiber-cemented clay (PCC) was investigated by using unconfined compressive test. The experimental results show that the addition of fiber with 1% content can increase the strength as well as the ductility of cemented clay by 12.5% and 15.6%, respectively. The strength of PCC and OCC at 22d age was 1.5 times than at 7d age. Under differently timed freeze–thaw cycles, the mechanical performance of PCC is improved, and, better than that, OCC improves by 11.8% in strength, 16.5% in strain and by 5% in degree of damage, indicating that fiber can improve the freeze–thaw resistance of cemented clay. The frost resistance of PCC and OCC increases with the increase in curing age. Finally, the variation of strength of OCC was explained through the change of micro-structure while the strength enhancing mechanism of polypropylene fiber for cemented clay was also revealed.


1997 ◽  
Vol 2 ◽  
pp. 113-120
Author(s):  
Yasushi TAKEUCHI ◽  
Masashi KOYANAGAWA ◽  
Tatsuo INUI ◽  
Tatsuo NISHIZAWA

2006 ◽  
Vol 43 (11) ◽  
pp. 1117-1130 ◽  
Author(s):  
J -M Konrad

Repeated-load triaxial tests were conducted on crushed granitic base-course material to study the resilient response under different stress paths and compaction states. It has been established that the resilient response of this prestrained unbound granular material is best defined in terms of tangent stiffness (Et) and vertical stress (σv). The data also revealed the existence of a threshold value of tangent stiffness that is essentially dependent on initial confining stress for a given compaction state. When the tangent modulus exceeds this threshold value, a unique relationship between tangent stiffness and vertical stress exists for mobilized shear resistance ratios less than 0.4. This Et–σv relationship is independent of stress path. A simple power law model can be used to predict the resilient response of unbound base-course material and an approximate value of resilient modulus for any desired stress path and initial stress condition. The use of the tangent stiffness – vertical stress model for pavement design appears to be very promising.Key words: granular, material, resilient modulus, triaxial, stress path.


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