scholarly journals Equivalent Resilient Modulus Inversion and Calculation of Different Asphalt Pavement Structures

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Mingming Cao ◽  
Wanqing Huang ◽  
Yiwen Zou ◽  
Zhiyong Wu
Keyword(s):  
Theoretical Calculation ◽  
Calculation Method ◽  
Resilient Modulus ◽  
Asphalt Pavement ◽  
Small Error ◽  
Crushed Stone ◽  
Base Layer ◽  
Inversion Method ◽  
Cushion Layer ◽  
Structural Layer

Based on the modulus inversion theory and the equivalent principle of deflection basin, by analyzing the deflection basin data of each structure layer measured by the FWD, the obtained equivalent resilient moduli of different structural layers in three different structures (a semirigid type Asphalt pavement and two inverted asphalt pavements) were compared. At the same time, the calculated equivalent resilient modulus of the top surface of the structural layer based on the inversion method was used to modify the existing theory formula. The results show that, with the inversion method and the theoretical calculation method, the calculated equivalent resilient modulus of the top surface of the cushion layer has a small error, but the theoretical calculation method overestimates the equivalent resilient modulus of the top surface of the cement stabilized crushed stone layer and the top surface of the graded crushed stone transition layer, especially for the inverted asphalt pavement; by contrast, the corresponding result of the inversion method is closer to the value in actual engineering. While determining the equivalent resilient modulus of the cushion layer, the influence of the thickness of the cement stabilized crushed stone layer needs to be considered, and the inverted asphalt pavement structure should adopt a thicker asphalt layer to reduce the modulus deviation; at the same time, the more the structural layers and the larger the difference in the interlayer modulus ratio, the larger the deviation of equivalent resilient modulus of the top surface of the base layer; for the inverted asphalt pavement and semirigid asphalt pavement, the correction coefficients of the calculation formula of the equivalent resilient modulus of the top surface of cement stabilized gravel layer are 0.35∼0.55 and 0.65∼0.75, respectively. The inversion method can be used to determine the equivalent resilient modulus of each structural layer of the inverted asphalt pavement and semirigid asphalt pavement, and its results can provide a basis for the design of the structure reconstruction of asphalt pavement.

scholarly journals Modulus Inversion Layer by Layer of Different Asphalt Pavement Structures

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Mingming Cao ◽  
Wanqing Huang ◽  
Yiwen Zou ◽  
Guomin Liu
Keyword(s):  
Transition Layer ◽  
Asphalt Pavement ◽  
Structural Characteristics ◽  
Inversion Layer ◽  
Crushed Stone ◽  
Inversion Method ◽  
Layer By Layer ◽  
Pavement Structure ◽  
Pavement Structures ◽  
Structural Layer

In order to improve the accuracy of modulus inversion of the pavement structure layer, a layer-by-layer inversion method was proposed to be compared with the traditional inversion method by inverting the modulus of each structural layer of the inverted asphalt pavement and semirigid asphalt pavement. The results show that the influence of cushion modulus on the modulus of inverted subgrade and modulus of cement-stabilized crushed stone is restricted by the cushion modulus and pavement structure characteristics, and the thicker cement-stabilized crushed stone layer is beneficial for improving inverted modulus of subgrade; besides, for the inverted asphalt pavement, the modulus of the graded crushed stone transition layer has a significant influence on the modulus inversion of cement-stabilized crushed stone. The modulus of the graded gravel transition layer inverted by these two methods is underestimated, the modulus of cement-stabilized gravel is overestimated using the traditional inversion method, and the inversion result of the inverted asphalt pavement is more significantly affected by the inversion method than the semirigid base asphalt pavement. Moreover, the modulus of the pavement structural layer is determined by the material and structural characteristics, and its recommended empirical value or the value in the indoor test does not conform to the actual value of the site; by contrast, the inversion modulus obtained using the layer-by-layer inversion method is closer to the actual value, which can be used in the design of similar pavement structures to accumulate data for determining the material modulus or the pavement structure adjustment coefficient in the pavement structure.

scholarly journals Laboratory characterization of reclaimed asphalt pavement for road construction in Egypt

2017 ◽  
Vol 44 (6) ◽  
pp. 417-425 ◽  
Author(s):  
E. Mousa ◽  
A. Azam ◽  
M. El-Shabrawy ◽  
S.M. El-Badawy
Keyword(s):  
Resilient Modulus ◽  
Asphalt Pavement ◽  
Road Construction ◽  
California Bearing Ratio ◽  
Base Layer ◽  
Coefficient Of Determination ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Load Duration ◽  
The Impact

This paper presents the engineering characteristics of reclaimed asphalt pavement (RAP), blended with virgin aggregate for unbound base and subbase layers. The proportions of RAP were 0%, 20%, 60%, 80%, and 100% by total mass of the blend. The experimental laboratory testing included index properties such as gradation, modified Proctor compaction, California Bearing Ratio, and hydraulic conductivity. Repeated load resilient modulus testing was conducted on the blends. The impact of load duration on resilient modulus was also investigated. A strong inverse trend was found between resilient modulus and California Bearing Ratio. An accurate model was proposed for the prediction of the resilient modulus as a function of stress state and reclaimed asphalt pavement percentage with coefficient of determination of 0.94. Finally, multilayer elastic analysis of typical pavement sections with the base layer constructed of virgin aggregate and reclaimed asphalt pavement blends showed good performance.

The Study on Road Performance and Pavement Structure Analysis for the Base Layer Material Stabilized by SRX

2012 ◽  
Vol 594-597 ◽  
pp. 1402-1406 ◽  
Author(s):  
Yue Zhang ◽  
Yun Long Zhao ◽  
Bao Yang Yu
Keyword(s):  
Resilient Modulus ◽  
Asphalt Pavement ◽  
Base Material ◽  
Base Layer ◽  
Rigid Base ◽  
The Road ◽  
Flexible Material ◽  
Calculation Results ◽  
Road Performance ◽  
Pavement Structure

In order to overcome the weakness of semi-rigidity base layer，the road performance of the SRX(Solution Road RomixSoilfix) stabilized base material and the mechanics response of asphalt pavement with the base layer stabilized by SRX have been studied in this paper. The CBR value and resilient modulus of SRX stabilized base material were given by indoor test. Based on the multiple layer elastic theory, both the mechanical responses of asphalt pavement structure with the SRX stabilized base and semi-rigid base were given, and according to the calculation results, the two kinds of pavement structure fatigue life were analyzed. The results have shown that the CBR value of SRX flexible material is greater than that of graded crushed stone; the SRX stable material can be used as pavement base layer, but the fatigue performance of SRX flexible base materials should be paid much attention.

scholarly journals Analysis of Seepage Characteristics of a Foundation Pit with Horizontal Waterproof Curtain in Highly Permeable Strata

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1303
Author(s):  
Chenghua Shi ◽  
Xiaohe Sun ◽  
Shengli Liu ◽  
Chengyong Cao ◽  
Linghui Liu ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Theoretical Calculation ◽  
Calculation Method ◽  
Design Method ◽  
Water Pressure ◽  
Water Inflow ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Seepage Characteristics

At present, jet-grouted horizontal waterproof curtain reinforcement has become an essential method for deep foundation pit groundwater control. However, there is still a lack of an effective theoretical calculation method for horizontal waterproof curtain reinforcement, and there is little research on the seepage laws of foundation pits under different horizontal waterproof curtain conditions. Based on Darcy’s seepage theory, theoretical analysis models of deep foundation pit seepage were established considering the effect of a horizontal curtain in a highly permeable formation. Through the established models, the calculation method of the water inflow and the water pressure under the condition of a horizontal curtain was derived. Then through indoor tests, the reliability of the theoretical calculation method was verified. Furthermore, the established theoretical calculation method is used to analyze the influence of various factors on the water inflow and the water pressure, such as the ratio of hydraulic conductivity of the horizontal curtain to surrounding soil, thickness, and reinforcement position of the horizontal curtain. It is found that the hydraulic conductivity ratio has the most significant influence on the seepage characteristics of the foundation pit. Finally, the design method was applied to an example of the horizontal waterproof curtain of the foundation pit, which is located at Juyuanzhou Station in Fuzhou (China). The water inflow per unit area is 0.36 m3/d in the foundation pit, and this implies that the design method of the horizontal waterproof curtain applied for the excavation case is good and meets the requirements of design and safety.

scholarly journals Performance Evaluation of Hot Mix Asphalt with Different Proportions of RAP Content

2018 ◽  
Vol 34 ◽  
pp. 01026
Author(s):  
Ahmad Kamil Arshad ◽  
Haryati Awang ◽  
Ekarizan Shaffie ◽  
Wardati Hashim ◽  
Zanariah Abd Rahman
Keyword(s):  
Hot Mix Asphalt ◽  
Resilient Modulus ◽  
Design Method ◽  
Asphalt Pavement ◽  
Cost Savings ◽  
Volumetric Analysis ◽  
Public Works ◽  
Asphalt Binders ◽  
Moisture Susceptibility ◽  
Asphalt Mixes

Reclaimed Asphalt Pavement (RAP) is old asphalt pavement that has been removed from a road by milling or full depth removal. The use of RAP in hot mix asphalt (HMA) eliminates the need to dispose old asphalt pavements and conserves asphalt binders and aggregates, resulting in significant cost savings and benefits to society. This paper presents a study on HMA with different RAP proportions carried out to evaluate the volumetric properties and performance of asphalt mixes containing different proportions of RAP. Marshall Mix Design Method was used to produce control mix (0% RAP) and asphalt mixes containing 15% RAP, 25% RAP and 35% RAP in accordance with Specifications for Road Works of Public Works Department, Malaysia for AC14 dense graded asphalt gradation. Volumetric analysis was performed to ensure that the result is compliance with specification requirements. The resilient modulus test was performed to measure the stiffness of the mixes while the Modified Lottman test was conducted to evaluate the moisture susceptibility of these mixes. The Hamburg wheel tracking test was used to evaluate the rutting performance of these mixes. The results obtained showed that there were no substantial difference in Marshall Properties, moisture susceptibility, resilient modulus and rutting resistance between asphalt mixes with RAP and the control mix. The test results indicated that recycled mixes performed as good as the performance of conventional HMA in terms of moisture susceptibility and resilient modulus. It is recommended that further research be carried out for asphalt mixes containing more than 35% RAP material.

Analysis of Weighting Coefficients of Post-Assessment Indexes for Cold Recycling Engineering of Asphalt Pavement Based on Hierarchy Analytic Procedure

2012 ◽  
Vol 204-208 ◽  
pp. 1857-1863
Author(s):  
Min Jiang Zhang ◽  
Wen Bo Zhang ◽  
Bao Yang Yu
Keyword(s):  
Asphalt Pavement ◽  
Base Layer ◽  
Environmental Benefit ◽  
Analytic Hierarchy ◽  
Analytic Procedure ◽  
The Road ◽  
Technology Project ◽  
Recycling Technology ◽  
Cold Recycling ◽  
Post Assessment

Based on the theory of hierarchy analysis, the post-assessment indexes system of cold recycling technology project have been established, and the hierarchy analytic procedure have been used to determine the weighing coefficients for post-assessment indexes of cold recycling engineering of asphalt pavement, and the weighing values for various levels factors were given for the cold recycling base layer project of highway of Shenyang-Yingkou. Considering the road performance and economic benefit, societal and environmental benefit, the analytic hierarchy procedure (AHP) method can effectively avoid making wrong decisions subjectively and made it more scientific and reasonable to determine the weighing values of post-assessment indexes, and it is an effective method to determine the weighing values for post-assessment indexes of the cold recycling technology project.

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