New Technologies in Construction and Rehabilitation of Portland Cement Concrete Pavement and Bridge Deck Pavement

Pavements on orthotropic steel bridge decks in China have typically lasted three to seven years until the introduction of Epoxy Asphalt at the 2^nd Yangtze River Bridge at Nanjing. The thermoset nature of Epoxy Asphalt compared to the thermoplastic bitumen paving materials previously used accounts for its ability to satisfy the requirements of skid resistance, a uniform riding surface and steel deck waterproofing for extended years even under severe ambient and load conditions. As of the end of 2008 over 500,000 square meters of Epoxy Asphalt have been installed on 20 orthotropic steel bridges in China. These installations are performing very well with few problems. Extensive laboratory test programs have been conducted to characterize the properties of this unique paving material. Although there are strict time and temperature constraints in the construction of Epoxy Asphalt pavements Chinese contractors have quickly learned how to install these pavements without significant problems.

Asphalt mixtures have been widely used for wearing surfaces on steel decks of long-span bridges. Due to the unique mechanical and environmental conditions of steel decks, requirements for paving materials and paving patterns are different from those for regular road pavements. Currently there are no commonly adopted design theories or procedures for steel bridge deck surfacing. Premature failures of deck pavements have often been observed on steel bridges, particularly on the newly-built long-span bridges in China. Therefore, two main objectives are identified in this paper as: 1) integrating the separate design processes for the bridge structure and the deck pavement into one interactive process; 2), establishing the methodology of determining pavement system parameters. Systematic research has been conducted to develop the design theory and procedure, from many aspects including pavement materials and structure, mechanistic characteristics of the wearing surfaces on steel decks, fatigue properties, axle-load equivalency conversion, and optimization design procedure. The empirical-mechanistic approach is employed for the optimization of design. The case study shows that it is more feasible to consider the orthotropic deck and its pavement as a whole structural system during bridge design.

This study presents a rehabilitation method for the bridge deck pavement which has been damaged due to a moisture related failure of the asphalt concrete. In order to quickly drain the water which has infiltrated into the bridge deck pavement, this rehabilitation method adopts a new drainage system including a porous asphalt concrete layer and a polymer concrete based waterproofing layer so that the water cannot stay and cause moisture-related failure on the bridge deck. The most important factors for this drainage system are to meet satisfactory performance of the repairing material for the damaged concrete bridge deck, the waterproofing layer, and to develop a fast-track construction technique with a limited traffic blocking time. The porous asphalt mixtures for the new drainage system was suggested with the maximum aggregate size of 10mm, and was validated through various physical and mechanical laboratory tests to confirm its performance characteristics. In this study, methyl methacrylate (MMA)-type material was introduced for the water-proofing on the concrete bridge deck and damaged bridge deck repairing, and the results from a series of mechanical tests for evaluating the performance of the MMA material shows it has good capability for waterproofing and repairing of the concrete bridge deck which is subject to a moisture-induced neutralization of the cement concrete. In addition, to evaluate the field performance of the new rehabilitation method, a field study was conducted on a real bridge. Field performance observations on both the MMA and pavement materials indicated that the new method performs much better than traditional methods in draining water that has infiltrated into pavement layers.

The bascule bridge is one of the most appropriate bridges for ports and inland rivers from structural and economic viewpoints. However, the difficulty in successfully paving steel deck pavement remains to be solved for its wide applications. Serious premature failures of the pavements are found on many bascule bridges. So far, there is little discussion about this issue. In this study, the dynamic response of bascule bridge deck pavement was analyzed based on the different rotation velocities and different pavement elastic modulus for the Haihe Bridge being built in Tianjin, China, one of the largest bascule type bridges in the world. The results indicate that the shear stress of the pavement will increase greatly when the main girder opens wide, and simultaneously the girder rotation angle and rotation speed will lead to the non-uniform distribution of the shear stress. Since it is hard to control the pavement modulus due to the changing environmental temperature in the real world, an appropriate rotation velocity is suggested for reducing the shear stress between the pavement and the steel deck.

The structural behavior of the double-layered asphalt concrete Huanghe bridge was analyzed by the FEM (Finite Element Method). The most critical loading location for the bridge pavement was determined, and the control indexes for the asphalt pavement established. For the most adverse loading cases, the variations of asphalt overlays around wheel paths were analyzed and the corresponding three-dimensional graphs presented. To determine the influences of horizontal cyclic loads on the control index, different asphalt overlays under various horizontal cyclic loads were analyzed. To simulate the boundary conditions, the bridge, including beams, arch ribs, suspenders, and pavement were analyzed. Experiments were conducted in coordination with the finite element analysis. A relationship between shearing and bonding strength under varying temperatures was established, also, the interlayer stable control index, and bonding strength under 15°C, were determined. An in-situ pullout test was performed using the pullout apparatus designed by the research team to verify the stability of inter-layers. (You need to provided the specific finding and results in the abstract)

The project design of epoxy asphalt concrete surfacing on the steel deck of Sutong Bridge is commended. The response of the layered pavement system under wheel load was analyzed by the Finite Element Method, and the key mechanics parameters of easily damaged layers were calculated and portrayed. The research showed that the notable draught stress in the surfacing layer and high shear stress in the binder layer are the cause of the deck pavement's poor performance. Reasonable structure and material design is the crucial factor for project success. The results can be a reference for paving design of steel decks.

Today, serious deterioration has occurred on concrete deck pavement in China. One reason for the problem is the interface slippage between the concrete deck and the pavement. An efficient interface treatment can solve the problem. The interface treatment contains two aspects: the concrete deck treatment and the adhesion layer. Concrete deck treatment can change the physical form of the concrete deck and is more reliable in improving the shear performance of the concrete deck pavement. This paper summarizes and presents a comparison through physical form analysis and indoor tests of three kinds of concrete deck treatment: manual work treatment, milling treatment and sandblast treatment. The test results show that milling treatment can improve shear performance more than sandblast treatment. This paper suggests a more reliable way to improve the shear performance of concrete deck pavement.

Bridge deck pavement suffers from more complicated stresses than ordinary pavement, and mechanical states of the paving layers are influenced by material design parameters. After mechanical computation, the effects of material design parameters on the mechanical state and the variation law of pavement are analyzed. Analytical results indicate that following the traditional HAM design method can not adapt to actual mechanical states, and easily result in usual distress types on the asphalt concrete paving. Economical and reasonable paving materials should be designed or developed according to mechanical paving characteristics, such as multilevel dense built-in modified HMA, fiber-reinforced asphalt concrete and modified SMA, which can harmonize paving layers as a whole, adapt to the deformations of bridge decks, improve the mechanical states of the paving layers, increase the service years, and offer some helpful references for similar bridge deck pavement design.

The context of this paper is the research on reinforcement of Dongguan Northern Bridge of the Guangzhou-Shenzhen highway in China by using mesh and steel fiber reinforced concrete (SFRC). Numerical program MIDAS has been utilized to model the mechanical response of the bridge. The interaction between the new and old concrete bridge structures is simulated. Mechanic analysis has been performed on the most unfavorable load positions. The overloads and shrinkage creep of concrete are considered. The anchor bar's distance and the optimal thickness of the concrete bridge deck have been discussed. Finally, a real life application of the construction technology for treating the flaws of the bridge deck paving overlay with mesh and steel fiber reinforced concrete is given.

Orthotropic steel bridge decks are widely used for large and medium span bridges, however early failure in traditional asphalt concrete surfaces has proved to be a problem on high traffic routes. Consequently, a demand exists to find a durable overlay for such bridges. In this paper, four kinds of design indices are explored, based on the primary types of pavement distress. In addition, the mechanics of surface wear on orthotropic steel bridges was analyzed by the Finite Element Method (FEM), which shows that the higher elastic modulus of the intermediate layer and/or the thicker the wearing surface, the less stress there is in the critical fatigue parts of the surface and the more favorable the wearing surface is. A new composite wearing surface system was presented, with a cement-based intermediate layer, shear stud connector, and SMA13 surface. Also, a number of small-scale tests were conducted to investigate the performance of bonding the new composite overlay to a steel plate, such as the thermal compatibility, rutting test under high temperature, and fatigue durability of the new composite wearing surface system. These were then compared to the traditional double-layer asphalt concrete surface. It was concluded that the performance of the new composite system is more durable than the traditional one.

Rigid concrete pavement slab under various supporting conditions was analyzed by elasto-plastic nonlinear three-dimensional finite element technique. The influences of void size on the stress, and deflection of concrete pavement slabs were investigated and are presented in this study. This research shows that the stress peak value of a loaded slab is approximately two times higher than at the across corner slab. Due to stress concentration, the void area boundary of PCC slabs becomes a fracture boundary, because it eventually ends up as a corner crack. The deflections of loaded slabs grow rapidly when the tire load approaches the center of the slab. As expected, the highest deflection occurred at the location directly below where the tire load was applied. In addition, the deflections increase directly with increases in the void size.

The fatigue destructive model which considers the temperature fatigue stress in airfield cement concrete pavement was introduced. The distribution rules for four main parameters were developed by measurement and analysis. The Reliability Calculation Program for Airfield Cement Pavement (RCPACP) was compiled based on Monte Carlo Method. The ranges of variability coefficients of parameters were described and the sensitivity of the parameters was qualitatively and quantitatively analyzed based on the program. The results show that the sensitivity of flexural flexibility modulus of concrete is largest and the flexibility modulus on top of the base is smallest.

A thin-bonded CRCO (Continuously Reinforced Concrete Overlay) on a JCO (Jointed Concrete Overlay) was constructed at Seo Hae Ahn Express Highway in Korea. This project includes two experimental sections: 1 ) a JCO with saw-cut joints over existing transverse joints, and 2) a CRCO, which employs transverse and longitudinal steel reinforcing rods, that is placed on top of an existing JCO. After milling 5 cm off the top of the JCO, an overlay thickness of 10 cm remains. Several VWSGs (Vibrating Wire Strain Gauges) were installed to evaluate curling, delamination behavior, and crack propagation of the thin-bonded CRCO. This paper describes the early behavior of this overlay and compares the current and new rehabilitation methods available in Korea.

Generally, Ultra Fine Fly Ash (UFFA) has the advantage that it advances greater concrete workability and that it activates a greater pozzolanic reaction than common fly ash due to its ultra fine particle size. These properties enhance concrete durability by reducing permeability and increasing resistance to alkali silica reaction (ASR) and sulfate attack, etc. For these reasons, UFFA can be used in rapid setting concrete. The purpose of this study is to develop and evaluate the rapid setting concrete with UFFA as a repair material for early-opening-to-traffic. In previous studies, if only UFFA is added to the rapid setting concrete mixture, the pozzolanic reaction does not happen actively. In this study, the chemical and physical tests were performed for rapid setting concrete with a combination of UFFA and calcium hydroxide. This enabled the activity of pozzolanic reaction to be evaluated as well as the effectiveness of this mixture on enhancing concrete durability was investigated. This study found that adding UFFA decreased the water/cement ratio of concrete and compensated the reduced portion of the early strength of concrete. Additionally, rapid setting concrete with UFFA and calcium hydroxide activated a greater pozzolanic reaction than normal-UFFA concrete. As the calcium hydroxide increased, the electrical indication of the concrete's ability to resist chloride ion penetration was promoted significantly.

Longitudinal cracking and longitudinal joint separations are commonly observed distresses in concrete pavements. The Texas Department of Transportation instituted a research project to determine the causes and to recommend repair methods. Repair methods that are generally recommended to repair cracks and joints are (1) cross stitching; (2) slot stitching; and (3) stapling. Finite element modeling was performed to determine the stress distribution in the concrete for each method when a truck tire load was placed on one side of the joint. Assuming no interlock between joint faces, the slot stitching model produced the lowest stress and cross stitching produced the highest stress, when the load was placed on the upper end of the diagonal bar. Cross stitching is recommended for repairing narrow cracks and slot stitching is recommended for wider cracks and joints.

Based on deflections from theoretical analysis and falling weight deflectometer (FWD) at the slab center and corner, a method was established for the estimation of void size at the slab corner. Also, by modifying joint load-transfer capacity based on the theoretical slab corner deflection in infinite site slab under even supporting conditions, the theoretical slab corner deflection was calculated, and compared with FWD testing data to estimate the void conditions beneath the slab corner. A concept of void index was developed, which is defined as the ratio of deflections of testing in slab corner under FWD load against theoretical deflections. Through analyzing the relations between void index and other factors such as void size, slab modulus, slab thickness and foundation reaction modulus, the regression formula between void index and void size was established for the estimation of void size. The results of void identification using the method proposed in this study with the data from the test section at the Hunan Leiyi Expressway compare reasonably well with the actual condition, which proves the reasonableness and viability of the method proposed in this study.

The bump on bridge-approach has been an urgent worldwide problem on highways and bridges, caused by differential settlement between bridge abutment and approaching pavement. But the existing calculation models and methods of bridge-approach pavements could not describe and explain the mechanism of bump under vehicle dynamic load appropriately. So this paper adopts human weighed acceleration RMS (Root Mean Square) to evaluate ride comfort when the vehicle is passing through bridge-approach, and road unevenness model of bridge-approach is build up by exponential settlement curve, and effect factors of vehicle ride comfort are analyzed that velocity, the maximum differential settlement and settlement length have the important effect on people ride comfort. At last, the author builds up differential settlement control criterion of bridge-approach on people-vehicle-road interaction.

A concrete slab edge will tend to curl up when it is subjected to a negative temperature gradient extending through the slab thickness. The tendency to curl up can induce tensile stresses on the top of slab as the pavement is restrained by its weight or other factors. At present in cement concrete pavement design in China the total stress as a result of load stress plus temperature stress results in transverse crack from the bottom to top of the slab is the only transverse crack considered. In recently many researchers have noticed top-down cracks in concrete pavement slab, and the top-down cracking has been observed in China through coring. Therefore, in order to understand the influences of coupling curling and loading stress on slab cracking, the single slab resting on elastic foundation with frictionless interface is simulated by finite element model (FEM). In FEM the axle load positions from an edge of the slab to another edge are considered and the negative temperature gradients are considered also. From the calculated results when a negative temperature gradient is combined with an axle load, high tensile stress will occur on the top of slab, so top-down cracking will occur. Therefore, in concrete pavement design the top-down cracking in concrete pavement should be considered in the design.

Sensitivity analyses for transverse cracking of Continuously Reinforced Concrete Pavement (CRCP) were investigated for the CRCP structure of Lei-Yi (Leiyang to Yizhang) Expressway in Hunan Province, China. The investigation included 13 main parameters (slab thickness, elastic modulus of steel, temperature shrinkage coefficient of steel, drying shrinkage strain, compression strength, creep coefficient of concrete, elastic modulus of concrete, temperature shrinkage coefficient of concrete, diameter and spacing of longitudinal reinforcement, base friction coefficient, reinforcement bond strength and temperature differences) at 5 different levels. The average crack spacing, the average crack width and the maximum reinforcement stress were simultaneously calculated with the iterative algorithms according to the one-dimension nonlinear analysis method. It considered the creep action and the nonlinear boundary properties that took into account the bond-slip between reinforcement and concrete, and the friction-slip between slab and base. The sensitivities of CRCP transverse cracking influenced by each factor were analyzed with the relative comparison method quantitatively and qualitatively. The results show that the main factors impacting the CRCP transverse cracking included shrinkage properties of concrete, concrete grade, spacing and diameter of reinforcement, and the grade and type of reinforcement.

Compressive strength of concrete is a very important parameter in the quality control of both new and existing concrete pavement. It has been widely used to evaluate the concrete strength both in the laboratory and in the construction field regardless of whether numerous mix designs or identical mixtures are used. Errors usually happen in the compressive strength test even if the mixture is evenly mixed and compacted into test specimens. This is caused by either by the hand-operated testing machine or by the eccentricity between the specimen and the testing machine. If concrete specimens with identical mix design need to be tested at various curing ages every time concrete is used in the construction field, the result is significant waste of time, money and efforts are required. Consequently, there is a real need to replace the repeated compressive strength tests with the introduction of nondestructive tests to estimate compressive strength of concrete. In this study, a nondestructive test method using elastic waves was used because shear wave velocity is not affected by restraint conditions. The compressive strength of concrete was estimated according to various curing ages as well. In the results, shear wave velocity was very closely related to the compressive strength. The results further showed that the estimation of compressive strength of concrete using shear wave velocity is very effective and reliable.

This paper presents the performance of continuously reinforced concrete pavement (CRCP) constructed in 1995 that utilized recycled concrete aggregate (RCA) as both coarse and fine aggregates. The project is Houston on a section of IH-10 between Loop 610 W and IH-45. In this project, no virgin aggregates were used. Concerns were raised regarding the performance of CRCP containing RCA. Detailed study was conducted to evaluate concrete material properties containing RCA. The properties of recycled aggregate measured in this study compared with virgin aggregate are consistent with those reported elsewhere: low specific gravity, higher water absorption, sulfate soundness loss, LA abrasion loss, and thermal coefficient. Little variation was observed in the paving operation due to the use of 100 % recycled coarse and fine aggregates. The moisture control of recycled aggregate, especially fine aggregate, is critical in producing consistent and workable concrete. The short-term and long-term performance of the reconstructed CRCP has been excellent, with tight crack widths and little spalling. Between concrete with virgin aggregates and concrete with recycled aggregates, there is no significant difference in thermal coefficient and permeability; however, there are significant differences in modulus of elasticity, compressive and indirect tensile strength, and water absorption. The low modulus of RCA concrete and good bond between recycled coarse aggregates and new mortar appear to be the key ingredients for good pavement performance. After more than 10 years of service under heavy traffic, the CRCP section containing 100% RCA is still providing excellent performance with no single structural distress.