Semi-rigid Pavement Research Articles

Strain response of a semi-rigid base asphalt pavement based on heavy-load full-scale accelerated pavement testing with fibre Bragg grating sensors

Full-scale accelerated pavement testing with a mobile load simulator 66 (MLS66) was conducted on a semi-rigid base asphalt pavement on a highway in Chongming Island, Shanghai, China. The goal was to investigate performance behaviour of an asphalt pavement with fine-sand subgrade in the river bed. Chongming is the terminal of G40 highway where fine sand is abundant. Although commonly found, there are little published data on its performance in a pavement structure. If found reliable in the accelerated test, the design would be used for the construction of G40 highway, which can lower the construction costs greatly and provide an engineering practice for follow-up research. Performance of the pavement structure was evaluated under high-frequency heavy trafficking while being subject to high-temperature and ambient environmental impact. This included monitoring of strains, temperature, modulus, rutting deformation, pavement depth and water level. This paper discusses the cumulative and instantaneous three-dimensional strain at the bottom of each layer in the semi-rigid base asphalt pavement. Generally good agreement was reached between the measured and calculated strains with back-calculation resilient modulus considering modulus reduction of asphalt layers because of temperature. A fatigue equation of the asphalt layer was established between loading applications, strain and seismic modulus, a small-strain value of Young's modulus. Conclusions regarding the spatial distribution, time-history change of three-dimensional dynamic strain response and the relationships between influencing factors and strains are presented.

Effect Analysis of Vehicle System Parameters on Dynamic Response of Pavement

In order to study the damage of a semirigid pavement under vehicle loads with varied parameters, the random dynamic loads applied on the pavement by a running vehicle were computed with two degrees of freedom, quarter-vehicle model, and then a three-dimensional finite element analysis model of semirigid asphalt pavement was established. With the peak stress index of each pavement layer, the effect of varied vehicle parameters on pavement response was studied. The results indicated that the stress wave frequency of each pavement layer was similar to that of the dynamic random load, and, with increased pavement depth, the wave effect decreased. The pavement response increased with increased suspension stiffness and tire stiffness and decreased with increased suspension damping and tire damping. Furthermore, compared to the stiffness, the response variation induced by the damping was orders of magnitude lower. Compared with the traditional time response analysis method, the peak response analysis of the pavement structure was more scientific, rational, and intuitive, which could be useful for the study of vehicle-pavement interaction and road damage.

Development of new „Catalogue of typical flexible and semi-rigid pavement structures”

This publication describes research and design works which were conducted at the Gdansk University of Technology for the purpose of development of new catalogue of typical flexible and semi-rigid pavement structures. The studies included: standardization of pavement structures terminology, study of foreign pavement structures catalogues and design methods, analysis of fatigue criteria for design of flexible and semi-rigid pavements, analysis of road traffic, based on weight in motion data, design of subgrade improvement, incorporation of new pavement materials, recycled and anthropogenic materials, determination of mechanistic parameters of materials and design of pavement structures using mechanistic-empirical methods of pavement design.

Grey Relational Analysis of Fatigue Performance of Semi-Rigid Pavement Structure

A number of different semi-rigid pavement structure models are established to perform calculation and the results are led into the calculation software nSoft to analyze and acquire the fatigue property of different semi-rigid pavement structure models. The grey relational analysis of different semi-rigid pavement structure models fatigue properties are done based on the grey system theory to gain the key influence parameter on semi-rigid pavement structure fatigue performance. The research conclusion has certain instruction function to design pavement structure with excellent anti-fatigue performance.

Application of Pre-Cracking in Semi-Rigid Base to Mitigate Reflective Cracking

Because of the high strength and sound stability, the cement stabilized base has been widely used in high grade pavement in China. But shrinkage cracking are easy to occur in the cement stabilized base. Under the repeating action of traffic loads and temperature loads, this kind of cracks are easy to propagate towards the asphalt surface, being called “reflective crack”. Shrinkage cracks are not normally avertable in the cement stabilized base, in contrast with a few wide cracks of broad spacing, numerous thin cracks of narrow spacing contribute little to the severe reflection cracking. On the basis of this thinking, the pre-cracking technique as a promising approach is brought forward. Several vibratory roller passes to the cement-treated base at a short curing stage, typically 1 to 3 days after placement, to create a fine network of cracks, which avoids the wide and/or long cracks and creates the ideal crack model. Comparing to wide cracking, the degree of the stress concentration resulting from thin cracking is by far mitigated. The Finite Element Method is used to predict the ideal crack model, and then the mechanical responses of the semi-rigid pavement of single wide cracking and net hairline cracking under vehicle loading are numerically simulated, simultaneously compared and analyzed. The simulation analyses indicate that the pre-cracking technique is a very useful tool to mitigate the reflective cracks.

Mechanical Response Analysis of the Composite Asphalt Pavement

With the constant increasing of traffic flow and axle load, the early failure of semi-rigid base asphalt pavement is increasingly serious in China. The bad durability and short service life of pavement have become main obstacles in road construction development. Based on the experience of successful application, the early failure of semi-rigid base asphalt pavement is solved, and the service life of pavement is increased by using of the composite asphalt pavement. To solve the design problem of the composite asphalt pavement , its mechanical properties influence results of are obtained by the factors, such as shear strain, shear stress, compression strain on top of subgrade, etc, by a lot of calculation using Shell pavement design software. These provide theoretical basis for durable asphalt pavement design based on rut-resistance property.

Rheological Properties of Asphalt Mixtures with Additives Based on Renewable Sources

The deformational properties and fatigue of asphalt layers are important for the design and assessment of semi-rigid and flexible pavements. The Two-point Bending Test was used for determination of deformational characteristics of asphalt mixtures on Department of Construction Management in Žilina. The results are evaluated with the KATEMS assessment software. The long-term research leads to estimation of deformational characteristics and fatigue of different types of asphalt mixtures. The tests have shown a positive impact of additives (ground rubber, hydrate lime component, recycling materials,...) on the results of these mixtures. This article is focused on assessment of deformational properties and fatigue of selected types of asphalt mixtures, there are viscoelastic materials in construction of pavement.

Modulus Back-Calculation Based on FWD Dynamic Deflection Basin for Semi-Rigid Base Asphalt Pavement

To study semi-rigid base asphalt pavement response characteristics, two structural APT test roads of cement stabilized aggregate and lime fly-ash stabilized aggregate were constructed, and accelerated loading test was developed. After certain number of wheel loads (70,000 times) pavement deflection basin parameters were detected by using the falling weight deflectometer, then modulus of each pavement layer was back-calculated, dynamic response was analyzed. Studies have shown that the modulus of semi-rigid base decay faster, and with decreasing thickness of the semi-rigid base, the greater the rate of decay of modulus; cement stabilized aggregate decay rate is greater than that of lime fly-ash stabilized aggregate.

Analysis of Stress and Strain for Semi-Rigid Asphalt Pavement Based on Accelerated Loading Test

Through the construction of cement stabilized macadam and lime-fly ash stabilized macadam road, and strain gauges, vertical stress sensors and temperature sensors were laid in the pavement during construction. Pavement structure dynamic stress, strain, deflection and pavement temperature were collected. The correlation between pavement temperature and structural dynamic response was analyzed. The results showed that, tensile strain of semi-rigid base layer was less affected by temperature; structural deflection was great affected by the thickness of semi-rigid base. After a certain number of repeated loads, the delay rate of tensile strain of semi-rigid base layer increased first and then slowly decreased.

Mechanics Analysis of Semi-Rigid Subgrade Pavement Structure

The semi-rigid base asphalt pavement structure was choose often used to the highway in our country, but the semi-rigid base asphalt pavement early damage almost has become a common phenomenon.In this paper, the rule and trend of mechanics response about pavement structure (the vertical displacement and tensile stress) were analyzed under the semi-rigid base choose different elasticity modulus and thickness by ANSYS for muti-layer foundation of semi-rigid base pavement design to provide reference.

Mechanics Analysis of Flexible Base Pavement Structure

With the rapid development of traffic cause in our country, the operating requirement of driving load factors to pavement structure become higher and higher. The Semi-rigid base asphalt pavement structure exposed some defects and shortcomings, so the study of flexible base asphalt pavement structure is put on the agenda under the circumstances.Based on the research achievements at home and abroad of the existing asphalt pavement structure , choosing different elastic modulus and thickness to calculate and analyze the flexible base by ANSYS, gaining the law and trend of mechanics response (the vertical displacement and tensile stress) about pavement structure for the flexible base pavement of each layer foundation to provide the design reference.

Loading capacity strengthening to cement-stabilised crushed gravel using reinforced wire mesh

Settlement and non-uniform deformation of frozen soil subgrade introduce fatal cracks on semi-rigid base asphalt pavements. This research aims to use reinforced wire mesh to reduce serious cracks on semi-rigid asphalt pavements in frozen regions. Three impact factors, diameter and interval as well as two types of wire mesh have been analysed by loading tests. Results have shown that after setting the reinforced wire mesh: (a) failure load and displacement of the cement-stabilised crushed gravel samples have been improved; (b) diameter and interval of the wire mesh have interactive impacts on reinforced sample load capacity; (c) the reinforced wire mesh can limit cracks by redistributing stress in the specimen; and (d) the multiple linear regression model well reflects the variation of loading properties; the results make sense from the statistics view as well. Results also represent that the strengthened wire mesh can help spread out the applied load, and increase the overall loading capacity of cement-stabilised crushed gravel. The results provided a reference for semi-rigid base asphalt pavement cracks caused by non-uniform deformation on frozen soil subgrade as well as guidelines for construction and maintenance in frozen regions.

Sulfur Polymer Emulsion 및 보강용 섬유를 활용한 반강성 포장재의 공학적 특성

본 연구에서는 유황폴리머에멀젼 (SPE)을 반강성 포장용 주입재의 아크릴레이트 대체재로서 활용가능성과 성능향상재료 (PVA섬유)에 대한 역학적 성능과 내구성능을 평가하였다. 평가결과, 반강성 포장재의 충전률은 섬유의 혼입률이 증가함에 따라 충전률이 저하되었지만, 모든 배합조건에서 평균 92~94%로 측정되어 목표 성능인 90%를 만족하였다. 반강성 포장재의 마샬안정도 값은 최대 25.4kN으로 측정되어 반강성 포장재의 국내 기준인 5.0 kN 보다 약 4.7배 우수한 것으로 나타났다. 반강성 포장재의 동적안정도 평가결과, 휠 트래킹시험에 따른 변형저항성은 SPE를 대체한 배합조건이 보다 우수하였고, 모든 배합조건에서 45분 이후에는 변형량이 일정한 값에 수렴되어 동적안정도가 31,500회/mm로 동일한 결과를 나타내었다. 파단변형률은 최대 0.53% 정도로 나타나 아스팔트 포장재보다 우수한 강성으로 나타났다. 마모저항성 및 충격저항성 검토결과 모든 배합조건에서 손실률이 9.8~6.0%로 나타나 우수한 내마모성을 나타내었으며, 섬유를 0.3% 혼입한 경우 혼입하지 않은 Plain에 비하여 2.82배의 내충격성 향상을 나타내었다. 역학적성능 및 내구성능 등을 모두 고려하여 볼 때, 이 연구 범위에서는 SPE 대체율 30%가 적정 수준이고, 혼입률 0.3% 범위에서 PVA 섬유를 적용하면 우수한 인성을 갖는 반강성 포장재 제조가 가능 할 것으로 판단된다. The application of sulfur polymer emulsion (SPE) as an acrylate substitute for semi-rigid pavement grout was evaluated, and the performance improvement by employing PVA fibers were also evaluated. The result indicated that the filling ratio of semi-rigid pavement material decreased as the fiber content increased, but it was measured to be 92~94% in every mixing condition, which satisfies the target performance, 90%. The maximum Marshall stability value of semi-rigid pavement material was measured to be 25.4 kN, which is about 4.7 times higher than the Korean Standard required for semi-rigid pavement material, 5.0 kN. The dynamic stability evaluation of semi-rigid pavement material indicated that the resistance to deformation from the wheel tracking test was improved by an SPE substitution, and in every mixing condition, the deformation converged to a constant value after 45 minutes with the same dynamic stability of 31,500 times/mm. The strain at the flexural failure was about 0.53%, which shows superior rigidity to asphalt pavements. The examination of abrasion resistance and impact resistance showed that the loss ratio was 9.8~6.0% in every mixing condition, which indicates a good abrasion resistance. Also, when fiber content ratio was 0.3%, the impact resistance was 2.82 times higher compared to plain (i.e., when fibers were not added). In the limited range of this study, an SPE substitution ratio of 30% was found to be an optimal level considering the mechanical and durability performance. In addition, it is thought that semi-rigid pavement material with superior performance could be manufactured if fiber content ratio up to 0.3% is applied depending on the purpose of use.

Study on the fatigue test of cement bound granular CBG-25

Semi-rigid pavement is the most common road structure in China and the performance of this kind of pavement is significantly determined by semi-rigid base. However, the research of semi-rigid material is far behind the research of asphalt mixture. Cement bound granular CBG-25 (hereafter CBG-25) is a kind of semi-rigid material, and its fatigue performance is studied in this paper. A new fatigue test method is applied to make a study of CBG-25. What's more, traditional semi-rigid material's fatigue test method is conducted to make a comparison. Both of these tests apply repeated load of four-point bending method. From this study, parameters for CBG-25 fatigue models are achieved by different test inputs and material parameters. The findings indicating the new test method and theory are proper to make the study of fatigue performance of CBG-25. Furthermore, we can do similar research with more other semi-rigid materials.

Influence of Heavy Axle Load on Dynamic Response of Semi-Rigid Base of Asphalt Pavement

In order to study the dynamic response law of semi-rigid base of asphalt pavement under heavy load traffic, the viscoelastic system model under heavy load was established based on measured loading pattern and axle load distribution with the finite element software ANSYS12.0. Heavy load traffic effect on the dynamic response of semi-rigid base of asphalt pavement was discussed . The results show that semi-rigid asphalt pavement structure dynamic response value changed with the increase of axle load; time varying regularity of stress and strain was not the same in different directions.

The Effects of Expansive Additive on Rapid Hardening Cement Grout for Semi-Rigid Pavement

Semi-rigid pavement, which mitigates the drawbacks of cement concrete and asphalt concrete pavements, is being widely used, but the body of research on enhancing the performance of cement grout remains limited. This paper discusses basic research on the development of a rapid hardening cement grout for semi-rigid pavement that meets chloride resistance, rheological property, and strength requirements. Evaluation results indicate that with up to 10% addition of expansive additive, in terms of the weight fraction of cement particles, the rheological property and strength requirements were satisfied. Examination of the chlorine ion penetration resistance revealed that an increase of expansive additive content yielded lower numbers of charged chlorine ions, resulting in 75.5 times higher resistance over a plain mix designed without expansive additive. In contrast, it was found that excessive addition of expansive additive, that is, beyond 10% in terms of the weight fraction of cement particles, was detrimental to achieving the desired rheological property.

Response of Perpetual Pavement under Different Axle Heavy Truck

To investigate suitability of the perpetual pavement under ultra-heavy loads, a test road was constructed on expressway in Shandong province of China. There were five pavement structures include semi-rigid asphalt pavement, each was instrumented with gages for measuring the strains of asphalt base layer, the vertical stress of subgrade, temperature of asphalt layers. The analysis of the strain data indicated that the strain values are affected by the temperature, the vehicle load, axle type, and the pavement structure combination. To research the response of different structure, tested different axle and load at different temperature, then different pavement response models were developed that accounts for layer thickness, axles load, pavement temperature and equivalent modulus of pavement foundation. The models provides good references under heavy vehicle loading and China local climate, it will be useful for perpetual pavement design.

Analysis of Perpetual Asphalt Pavement Response under Heavy Loads in Northeast Area of China

Severe rutting, cracks and moisture damage are presented on conventional semi-rigid base asphalt pavements not long after completed in China. This phenomenon indicates that conventional philosophy on pavement design could not meet more and more frequent and heavy vehicle. With high structural capacity for high traffic volume and heavy loads, the Perpetual Asphalt Pavements (PAPs) solve those problems well. Meanwhile they need minimal or no major structural rehabilitation and/or reconstruction exercises in their life, which ensures low user-delay. Three PAPs, including semi-rigid base asphalt pavement, flexible base asphalt pavement, and combined base asphalt pavement, are put forward for the northeast area in China considering its climate, traffic characteristic. Finite element method is utilized to analyze response of PAPs under heavy loads. Two key factors, i.e. tensile horizontal strains at the bottom of asphalt layers and compressive vertical strains are investigated. Also the capacities of the structures on bearing overloading are estimated. Four types of wheel and axle, including single axle and single tire, single axle and dual tires, dual axles and dual tires, and tri axles and dual tires are adopted in finite element models. The shapes of tire-pavement contact area are either circular or rectangular to simulate standard load or overloading respectively. When rectangular shapes are adopted, the contact area sizes and the distribution of pressure are varied. Conventional asphalt concrete and high modulus asphalt concrete are adopted. Simulations are done. The competences of the three pavement structures on fulfilling long lives are evaluated.

Semi-rigid pavement performance and construction techniques for semiarid areas

This article explains a field study about the service properties of semi-rigid pavements attained in a climatic area that can be considered semiarid/arid, located in the west of Spain. A semi-rigid pavement includes a soil-cement (SC) base (or subbase) and a stabilised subgrade. Taking as a reference the works in two motorways of recent construction such as the A-66 and A-58, the criteria are presented that favoured the choice of the semi-rigid solution for its pavement and the specific techniques used for its building as well as its performance after having been opened to the traffic for 7–8 years. It has to be noted, however, that the treated layers, especially the SC base, need to be protected by a specific thickness of bituminous layers in order to achieve a homogeneous distribution of the traffic loads and provide protection against water, as well as to absorb part of the thermal cracks that will inevitably appear. Nevertheless, in the considered weather conditions, the use of pre-cracking techniques is necessary in order to maximise cement content and obtain higher bearing capacity. The SC course, resting on a quality subgrade, is responsible to a great extent for the pavement final stiffness, being able to reduce the deformability of the subgrade itself to over 40%. The results reached with the International Roughness Index regularity rate on the treated subbases are presented as well, displaying its evolution with regard to the pavement construction phases and remarking on the recommended strategies for its improvement.

Pavement cold in-place recycling with hydraulic binders: the state of the art in France

The French road network, 95% of which consists of flexible and semi-rigid pavements, lends itself a priori well to in-place recycling. This article provides a summary of existing knowledge and rules of best practice with respect to the technique of cold in situ pavement reclaiming using hydraulic binders. The various aspects of this process are described in detail. The first approach is structural, it includes pavement mechanics and protection against frost/thaw. The second approach relates to the geometric rehabilitation of the facility. Lastly, the very significant sustainable development aspects are developed. For each of the aspects mentioned above, the general principles, the selection criteria for recycling equipment and binder, the assessment and control methodology are presented. The know-how specific to the various fields of applications is detailed. Typical examples are given.