Search Results (16)

The behavior of the cast-in-place continuously reinforced concrete (CRC) bus pad applied to bus stop pavement in a central bus-only lane was experimentally analyzed under environmental and moving vehicle loads, and the early-age performance of the CRC bus pad was evaluated using experimental data and finite element analysis results. Using various measurement sensors, the concrete slab strain, longitudinal steel bar strains, horizontal and vertical displacements, and crack behavior of the CRC bus pad due to environmental loads were measured, and the dynamic responses of the concrete slab and steel bars due to moving vehicle loads were also measured. Additionally, a method for converting strain gauge measurements of a cracked concrete slab to the strain of an uncracked concrete slab was also proposed. Under environmental loads, the range of stresses acting on the steel bars and the bond between concrete and steel bars were analyzed to be appropriate for ensuring excellent performance of the CRC bus pad. The crack widths and vertical and longitudinal displacements of the CRC bus pad were found to have no effect on the pavement performance. Within the vehicle velocity range used in this experiment, the strains of the slab and steel bars as the vehicle passed through the CRC bus pad were virtually independent of the vehicle velocity and were within a range that did not cause any reduction in pavement performance. This study confirmed that the CRC bus pad has excellent performance and can replace asphalt concrete bus stop pavement or jointed concrete bus pad. Full article

Road infrastructure serves as a foundational driver of a nation’s economic and cultural growth. Incorporating life cycle cost analysis (LCCA), as well as considerations of availability and environmental impact, enables policymakers to make strategic decisions that not only enhance fiscal efficiency but also support sustainable progress. This paper centers on an in-depth examination of two prevalent pavement technologies: continuously reinforced concrete pavements (CRCP) and jointed plain concrete pavements (JPCP). It specifically delineates the application of these methods to a hypothetical one-kilometer motorway construction in Germany. Employing LCCA for concrete pavements, the paper evaluates long-term fiscal prudence among alternative investment opportunities, factoring in resource utilization—both materials and machinery—and long-term care and upkeep obligations over the pavements’ operational lifespans. The analysis extends to appraise agency expenditures associated with the pair of pavement strategies and estimates the concomitant delay durations and costs relevant to the exemplar project. Central to this research is the investigation of road availability and its quantifiable influence on traffic efficacy, parsing through metrics such as the tally of days roads are out of service and the subsequent repercussions on vehicular flow. The investigation also proposes strategies for the reduction of embodied carbon in CRCP and JPCP systems. While accounting for variances in functional performance and vehicular comfort levels, this study contributes scientifically by tackling pragmatic engineering dilemmas involved in pavement selection, with a spotlight on minimizing costs, curtailing traffic interruptions, and mitigating ecological impacts for the duration of the pavement’s life cycle. Full article

Prefabricated pavement, with its advantages of a high paving speed, low material consumption, low carbon emissions, high strength, and easy construction, has gradually been used to address issues associated with traditional cement pavement construction. However, even under the long-term combined effects of vehicle loads and environmental loads, the joints between pavement slabs remain prone to various problems. This paper proposes the use of steel-fiber-reinforced self-stressing concrete (SFRSSC) with a certain level of self-stress for joint pouring and connection to control the development of cracks in the joints and achieve seamless integration between the slabs. Additionally, the self-stress generated by SFRSSC is utilized to enhance the continuity of the prestressed design in precast slabs, thereby extending their service life. Through laboratory experiments and field tests, the self-stress magnitude, mechanical strength, and long-term applicability of SFRSSC were studied. The results indicate that SFRSSC can achieve self-stress levels of over 7 MPa under standard curing conditions, but the values decrease significantly when removed from the standard curing environment. SFRSSC exhibits a compressive strength of over 60 MPa and a flexural strength of over 9 MPa, both of which exceed the requirements of the relevant standards, making it suitable for use as a pavement joint material. During long-term monitoring in the field, SFRSSC demonstrates favorable expansion effects and high stability. The longitudinal expansion remains stable at 100 με, while the transverse expansion exhibits minor shrinkage, maintained at around 25.2 με. Therefore, the application of SFRSSC in assembly-type prestressed pavement joints shows high applicability. Full article

In this study, cracking patterns and widths were analytically investigated in a continuously reinforced bonded concrete overlay (CRBCO), as they developed due to temperature change and drying shrinkage, as the environmental load for the sustainable management of deteriorated concrete pavements. The parameters of the concrete damaged plasticity (CDP) model used for the nonlinear finite element analysis (FEA) of the continuously reinforced concrete pavement were determined through comparison of the FEA results with the field crack survey results so as to be used in the nonlinear FEA of the CRBCO pavement. The total temperature change, which combines the actual temperature change with the temperature change converted from the drying shrinkage, considering stress relaxation, was adopted in the FEA as the environmental load applied to the CRBCO pavement. The locations and movements of the reflection and transverse cracks in CRBCO were investigated via FEA. The reflection cracks occurred in the overlay at all of the joints of the existing pavement. Only one secondary crack, with a width that was 5–6 times narrower than that of the reflection cracks, occurred between adjacent reflection cracks under various conditions. Thus, the crack width of the CRBCO was predominantly affected by joint movement in the existing pavement. In addition, the crack widths predicted by the CDP model were narrower than those predicted using the elastic model by approximately 10%. Therefore, crack movement in a CRBCO pavement can be reasonably predicted by the CDP model. Full article

Continuously reinforced concrete pavement (CRCP) is a representative type of concrete pavement constructed with continuous steel bars without intermediate transverse expansions. With reference to pavement conditions, CRCP is an exceptional type of concrete pavement according to the Highway Pavement Condition Index (HPCI) and International Roughness Index (IRI). The two main design methods for CRCP are AASHTO 86/93 and the Mechanistic–Empirical Pavement Design Guide (MEPDG). Because of limitations of the AASHTO 86/93 design method, the MEPDG method is more reliable. While incorporating the interactions among geometrics, pavement structure layers, material properties, subgrade, traffic, and environmental conditions, and the prediction values according to the MEPDG method, it matched the measured results of crack spacing and crack width. The MEPDG punchout, crack width and spacing, and load transfer efficiency (LTE) models were evaluated, and results were compared with the test sections in three European countries consisting of different construction details, which were investigated and recorded between 2019 and 2021. In this sense, a calculation tool was developed to consider the influence of different parameters in design process. In addition, sensitivity analyses were executed for the development of punchout, considering various input parameters. The track surveying and the evaluation of the results indicated that the design process can be improved with consideration of some criteria such as crack formation time or adjustment of the correlation between crack width and crack spacing. Due to the very important function of erosion and resulting pumping in the deterioration of CRCP, it is advisable to include the influence of the base layer and the influence of different shoulder type and heavy traffic volume or effect of deflection in the calculations. Full article

Driven by the huge thermal energy in cement concrete pavements, thermoelectric (TE) cement has attracted considerable attention. However, the current TE cement shows poor performance, which greatly limits its application. Herein, a series of Bi_0.5Sb_1.5Te₃/carbon nanotubes (CNTs) co-reinforced cement composites have been prepared, and their TE properties were systematically investigated. It was shown that the addition of Bi_0.5Sb_1.5Te₃ particles can effectively improve the TE properties of CNTs-reinforced cement composites by building a better conductive network, increasing energy filtering and interfaces scattering. The Bi_0.5Sb_1.5Te₃/CNTs cement composites with 0.6 vol.% of Bi_0.5Sb_1.5Te₃ exhibits the highest ZT value of 1.2 × 10⁻², increased by 842 times compared to that of the CNTs-reinforced cement composites without Bi_0.5Sb_1.5Te₃. The power output of this sample with the size of 2.5 × 3.5 × 12 mm³ reaches 0.002 μW at a temperature difference of 19.1 K. These findings shed new light on the development of high-performance TE cement, which can guide continued advances in their potential application of harvesting thermal energy from pavements. Full article

Nanomaterials are considered to be one of the game-changing features in the modern world and nanotechnology is mostly reputed as the next-generation industrial revolution due to the extraordinary characteristics possessed by them at their very small scale. Graphene and graphene oxide are two main nanoscale materials that have seen a drastic increase in their use in cement-based composites due to exemptional enhancements in terms of strength and durability that can be imparted to compromise the inherent flaws of concrete and other cementitious composites. The main aim of this study was to investigate the effect of graphene and graphene oxide on improving the performance of cement-based composites and, particularly, of continuously reinforced concrete pavements (CRCP), which is one of the emerging trends in the transport sector due to various advantages they bring in over conventional flexible pavements and unreinforced concrete pavements. Fresh, hardened and durability properties of concrete with graphene-based nanomaterials were studied and the past experimental data were used to predict statistical interferences between different parameters attributed to concrete. According to the review, graphene-based nanomaterials seem to be promising to overcome the various CRCP distresses. Simultaneously, the possibilities and hinderances of using graphene and graphene oxide in cement-based composites as a reinforcement are discussed. Finally, the potential of using graphene in continuously reinforced concrete pavements is explored. Full article

Based on thermal–mechanical coupling simulation analysis and physical engineering tracking observation, the mechanical behavior and response of a continuously reinforced concrete and asphalt concrete (CRC + AC) composite pavement layer were analyzed, and the causes of cracking on the surface and bottom of the asphalt layer were revealed. Studies have shown that under normal driving conditions, the AC layer, which is usually in the position of the wheel load gap and wheel load side, more easily generates a longitudinal “corresponding crack”. Compared to normal driving, longitudinal cracks are generated more easily inside of the curve, and transverse cracks occur more easily on poor stadia curves. When the AC layer thickness is less than 8 cm, the AC layer is more prone to bottom-up cracking, and it is more prone to top-down cracking when it is more than 8 cm thick. Comprehensively considering the tensile stress, shear stress, and the thickness of the AC layer, it is recommended that the suitable thickness range of the AC layer is 8 cm~14 cm. The calculated results show good agreement with the physical engineering investigation. The research results can provide a theoretical and scientific basis for cracking control and the rational design of a CRC + AC composite pavement layer. Full article

The Guide for Design of Pavement Structures (AASHTO 86/93) and Mechanistic Empirical Pavement Design Guide (MEPDG) are two common methods to design continuously reinforced concrete pavement (CRCP) published by the American Association of State Highway and Transportation Officials (AASHTO) in the USA. The AASHTO 86/93 is based on empirical equations to assess the performance of highway pavements under moving loads with known magnitude and frequency derived from experiments on AASHTO road tests. The MEPDG is a pavement design method based on engineering mechanics and numerical models for analysis. It functions by incorporating additional attributes such as environment, material properties, and vehicle axle load to predict pavement performance and degradation at the selected reliability level over the intended performance period. In order to evaluate the CRCP design procedure and performance, crack width (CW) and crack spacing (CS) from five examined test tracks in Europe with different climate condition, base layer, geometry, and materials were collected in this paper and compared with predicted distresses as well as CW and CS from AASHTO 86/93 and MEPDG design methods. The results show that the interactions between geometrics, material properties, traffic, and environmental conditions in the MEPDG method are more pronounced than in the AASHTO 86/93 and the prediction of CS and CW based on MEPDG matched closely with the recorded data from sections. Full article

A procedure for determining the optimized composition of layer properties for a continuously reinforced concrete pavement (CRCP) system was constructed using field tests, finite element (FE) analysis, and regression analysis methods. The field support characteristics of a rigid pavement system were investigated using a falling weight deflectometer (FWD), dynamic cone penetrometer (DCP), and a static plate load test. The subgrade layer exhibited a more uniform condition than the aggregate base, and the modulus of the subgrade reaction of the aggregate base and subgrade combination (effective k-value) was improved by about 1.5 times by introducing a 2 inch (50.8 mm) asphalt stabilized base (ASB) layer. Thereafter, FE support models describing the actual field conditions were studied. The effects of the thickness of the stabilized base layer, the elastic modulus of the stabilized base material, and the effective k-value on the composite k-value of the support system were identified using a regression analysis method, and the results showed that the variables had a similar effect when determining the composite k-value. Afterward, a procedure for selecting the layer properties for producing a suitable composite k-value was constructed, and we identified that the maximum stress in the concrete slab was induced at different levels, even with identical composite k-values. Lastly, regression relationships were derived to estimate the maximum stress in the concrete slab by considering both the support layer properties and the concrete slab. Subsequently, an algorithm for selecting an optimized layer composition of the CRCP structure was construction considering the economical aspect. Full article

The technological innovation of continuously reinforced concrete pavement (CRCP) that contains a significantly reduced amount of reinforcement and the same fundamental behavior as CRCP is called advanced reinforced concrete pavement (ARCP). This new concept of a rigid pavement structure is developed to eliminate unnecessary continuous longitudinal steel bars of CRCP by using partial length steel bars at predetermined crack locations. In Belgium, partial surface saw-cuts are used as the most effective crack induction method to eliminate the randomness in early-age crack patterns by inducing cracks at the predetermined locations of CRCP. The reinforcement layout of ARCP is designed based on the distribution of steel stress in continuous longitudinal steel bar in CRCP and the effectiveness of partial surface saw-cuts as a crack induction method. The 3D finite element (FE) model is developed to evaluate the behavior of ARCP with partial surface saw-cuts. The early-age crack characteristics in terms of crack initiation and crack propagation obtained from the FE simulation are validated with the field observations of cracking characteristics of the CRCP sections in Belgium. The finding indicates that there is fundamentally no difference in the steel stress distribution in the partial length steel bar of ARCP and continuous steel bar of CRCP. Moreover, ARCP exhibits the same cracking characteristics as CRCP even with a significantly reduced amount of continuous reinforcement. Full article

Since 1970, continuously reinforced concrete pavements have been used in Belgium. The standard design concept for CRCP has been modified through several changes made in the design parameters to eliminate the cluster of closely spaced crack patterns, since these crack patterns lead to the development of spalling and punch-out distresses in CRCPs. Despite adjusting the longitudinal reinforcement ratio, slab thickness, and addition of asphalt interlayer, the narrowly spaced cracks could not be effectively removed. The application of transverse partial surface saw-cuts significantly reduced the probability of randomly occurring cracks in the reconstruction project of the Motorway E313 in Herentals, Belgium. The field investigation has also indicated that the early-age crack induction in CRCP is quite susceptible to the saw-cut depth. Therefore, the present study aims to evaluate the effect of different depths and lengths of the partial surface saw-cut on the effectiveness of crack induction in CRCP under external varying temperature field. For this purpose, the FE software program DIANA 10.3 is used to develop the three dimensional finite element model of the active crack control CRCP segment. The characteristics of early-age crack induction in terms of crack initiation and crack propagation obtained from the FE model are compared and discussed concerning the field observations of the crack development on the active crack control E313 test sections. Findings indicate that the deeper saw-cut with longer cut-lengths could be a more effective attempt to induce the cracks in CRCP in desirable distributions to decrease the risk of spalling and punch-out distresses in the long-term performance of CRCP. These findings could be used as guidance to select the appropriate depth and length of saw-cut for active crack control sections of CRCP in Belgium. Full article

Cross-tensioned concrete pavement can reduce transverse joints and cracks and improve the durability of the pavement, and the decrease in slab thickness can be achieved without damaging the performance of the pavement. However, the corrosion of the steel can cause serious damage to the pavement structure, resulting in higher maintenance costs and shorter service life. Basalt fiber-reinforced polymer (BFRP) has been proven to be an effective alternative in both jointed plain concrete pavement (JPCP) and continuously reinforced concrete pavement (CRCP) due to its lightweight and corrosion-resistant properties. In this paper, a systematic theoretical method for determining the prestress loss of BFRP tendons in cross-tensioned concrete pavement was proposed, with the impact of the slab width and distribution angle of the prestressed tendon on the prestress loss being studied and compared to the results of traditional steel strands. Results showed that the proportion of the prestress loss due to anchorage deformation and prestress retraction in the prestressing stage rose with the increase in distribution angle and the decrease in slab width, while the prestress loss during the in-service stage was a constant value for both BFRP tendons and steel strands. The prestress loss of BFRP tendons was far lower than that of steel strands in both prestressing stage and in-service stage for a given slab width (3 m, 4.5 m, 9.0 m, 12.75 m) and distribution angle (20°, 25°, 30°, 35°, 40°, 45°), and the difference ranged from 6.4% to 16%, signifying the feasibility of BFRP tendons in cross-tensioned concrete pavement. Overall, the smaller the slab width, the greater the difference of the prestress loss between BFRP tendons and steel strands. Full article

Continuously reinforced concrete pavement (CRCP) is a pavement structure with a high performance and long service life. However, the corrosion of the longitudinal steel can result in a poor bond relationship between the steel and the concrete, affecting the load transfer efficiency between the adjacent panels and being responsible for the development of CRCP distresses. Basalt fiber-reinforced polymer (BFRP) is corrosion-resistant and has the potential to be used in CRCP. In this paper, the layout of a CRCP test section with BFRP bars constructed on G330 National Road in Zhejiang Province, China, is presented. An analytical model is proposed to predict the crack behavior of CRCP with BFRP reinforcement, with the predicted results are compared to field-measured ones. A sensitivity analysis of the BFRP design parameters on the crack spacing and crack width is conducted as well. The results show that the mean values for field-measured crack spacing and crack width are 4.85 m and 1.30 mm, respectively, which are higher than the results for traditional CRCP with steel due to the lower elastic modulus of BFRP. The analytical predictions agree reasonably well with the crack survey results. The higher the elastic modulus of BFRP, the reinforcement content (with both BFRP spacing and diameter related), and the bond stiffness coefficient between the BFRP and concrete, the less the crack spacing and crack width will be. Given the same or similar reinforcement content, a lower diameter with a smaller spacing is recommended because of its contribution to a smaller crack spacing and width. Full article

Industrial pavements are thin slabs on a continuous support subjected to restrained shrinkage and loads. The use of fibers as an alternative reinforcement to steel welded wire mesh and rebars is today an extensive practice for the reinforcement of concrete slabs-on-grade. Despite the widespread use of fiber reinforcement, the corresponding benefits in controlling cracking phenomena due to shrinkage are generally not considered in the design process of Fiber Reinforced Concrete (FRC) slabs-on-grade. The post-cracking performance provided by glass macro-fibers at low crack openings is particularly convenient in structures with a high degree of redundancy. Referring to service conditions, it is well known that concrete shrinkage as well as thermal effects tend to be the principal reasons for the initial crack formation in slabs-on-grade. A numerical study on the risk of cracking due to shrinkage in ground-supported slabs is presented herein. Special attention is devoted to the evaluation of the beneficial effects of glass fibers in controlling cracking phenomena due to shrinkage. The numerical analyses are carried out on jointless pavements of different sizes. Since shrinkage stresses in slabs-on-grade are considerably influenced by external constraints which limit the contractions, different subgrade conditions have been also considered. Full article