Airport Cement Concrete Pavement Research Articles

Investigating the interfacial vertical shear behavior of BFPMPC mortar and cement concrete with pothole repair

Magnesium phosphate cement (MPC) has both traditional cement properties and ceramic properties with fast setting and hardening characteristics. To rapidly reopen traffic and extend its service life, MPC has been widely used in the rapid repair of highway and airport cement concrete pavement. This study utilizes basalt fiber-reinforced polymer-modified magnesium phosphate cement (BFPMPC) developed in previous research to rapid repair the typical potholes on cement concrete pavement, aims to reveal the interface properties between BFPMPC mortar and cement concrete and further investigate the underlying mechanisms for such properties. Firstly, the optimal mixture ratio was determined by orthogonal test design. Then, the shear strength of the repair interface was measured by composite BFPMPC mortar and cement concrete specimens. The mechanical characteristics of the repair interface and the microscopic mechanism were characterized by nano-indentation technology and SEM/EDS. Finally, the interface constitutive model was established by DIGIMAT and finite element model was developed to simulate the interface failure. Results showed that the no new hydration products were produced by the addition of polymer in BFPMPC. BFPMPC matrix became denser with the increase of age, resulting in the better bonding between fiber and paste. The interface vertical shear strength at 6 h and 3 d were 3.1 MPa and 3.9 MPa, respectively. SEM/EDS results showed that polymer has a certain self-healing ability to decrease the crack width with increase of curing age, and a variety of inclusions in the repair interface were observed. The elastic modulus of each inclusion phase can be effectively analyzed by nanoindentation. The simulation results showed that the pressure on upper surface of BFPMPC mortar transfers to the bottom through the repair interface. As the tensile stress on the bottom over the maximum interface tensile stress, the cracks were extend from the bottom to upper, then the structure was failed. Interface vertical shear strength of numerical simulation was, respectively, 3.149 MPa and 3.957 MPa. It is close to the plain shear strength experimental value, validating the proposed interface constitutive relationship.

Bonding Performance and Microstructural Mechanism between Rapid Repair Materials and Old Concrete Pavement

In China, airports predominantly utilize airport cement concrete pavement, which inevitably undergoes deterioration in service. To uphold pavement durability and functionality, and ensure aircraft operational safety, prompt repairs of affected areas are imperative. Therefore, ordinary Portland cement mortars were used as the control group to compare and analyze the bonding performances of two common airport pavement repair materials: modified Portland cement mortars and phosphate cement mortars. Meanwhile, through microscopic experiments, the microscopic characteristics of the interfacial transition zone (ITZ) were studied, and the interface bonding mechanism was analyzed. The research results indicate that the interface bonding strength between phosphate cement mortar and old concrete pavement is the highest. This was because the elements in phosphate cement penetrated the old concrete pavement through hydration reactions, forming van der Waals forces and chemical bonding forces. In addition, the research results indicated that the presence of old concrete pavement made the three repair materials produce similar sidewall effects with the old concrete pavement, leading to a low hydration degree of the repair materials. However, the chemical bonding and penetrating structure of phosphate cement compensated for the weakening effect of the ITZ in the repair materials.

Characterizing fatigue damage behaviors of concrete beam specimens in varying amplitude load

In this paper, the random and nonlinear mechanical characteristics of the composition distribution of concrete in each phase are investigated to solve the difficulty of fatigue damage test of concrete beam specimens under variable amplitude loading. A three-dimensional (3D) concrete composite random aggregate meso-model of concrete beam specimens is built with Digimat as a composite modeling tool. Subsequently, the bending-tensile strength and fatigue life of the model under four-point bending loading is analyzed and calculated using Abaqus finite element analysis model based on the concrete elastic-plastic damage criterion. The mechanical behaviors of concrete materials under static load failure, multistage fatigue loading, and random fatigue loading are studied. Finally, compared with the test results, the following conclusions are obtained. The random aggregate model and elastoplastic damage mechanics model of concrete composite constructed by concrete in Abaqus and Digimat can better describe the geometric and distribution characteristics of composite structure and aggregate in concrete beams and the mechanical behavior of fatigue and static load failure. The difference is 4.08 % with the experimental results, which verifies the validity and reliability of the numerical simulation model, and the fatigue life of concrete beams under random loading Sra and Srb is 1622 and 164 times, respectively. The research results have certain guiding significance and reference value for accurate calculation of bending and tensile strength of concrete beams under specified raw material and mix ratio and prediction of fatigue damage cracking in airport cement concrete pavement structure.

ANALYSIS OF THEORETICAL BASIS FOR ASSESSING THE BEARING CAPACITY OF AIRPORT CEMENT CONCRETE PAVEMENT IN VIETNAM BY THE DYNAMIC DEFLECTION EQUIPMENT

This article presents the theoretical basis of the backcalculation method for determining the bearing capacity of the airport cement concrete pavement on the basis of the deflection data obtained in the field and the calculation results according to specialized software of the dynamic deflection equipment. Through experimental data of measuring actual deflection at taxiway S in Tan Son Nhat airport, compare the calculated bearing capacity according to the backcalculation theory and outputted value from the software has an error of 4% to 7%. It can be seen that, the backcalculation method of bearing capacity in cement concrete pavement according to the theory of multi-layer system structure gives similar results with the results calculated according to the specialized software of dynamic deflection equipment. The research results serve as the basis for evaluating the ability to use the existing dynamic deflection equipment in the world, for assessing the bearing capacity of the airport cement concrete pavement in the conditions of Vietnam.

Investigation on Surface Crack Resistance and Curing Measures of Airport Cement Concrete Pavement during Construction in Strong Wind and High Temperature Weather

The airport cement concrete pavement is prone to surface shrinkage cracks during construction under strong wind and high temperature conditions. Based on this, in this paper, the influence effects and mechanisms of curing methods on early shrinkage and crack resistance of concrete were investigated through indoor tests to simulate strong wind environment and high temperature environment in summer, and the applicability of different curing methods in engineering practice was verified by on-site experiments. The indoor experiment results demonstrated that the concrete was more prone to cracks under strong wind than under high temperature. The indoor and on-site experimental results showed that it was difficult to ensure a crack-free concrete surface by employing traditional geotextile, simply spraying curing agent or using only water-saving moisturizing curing film, among them, utilizing composite geotextile curing film has the best anti crack effect. In addition, incorporating polymer water absorbent resin enables the concrete to be cured internally, so it can be used as a supplementary curing measure to further improve the crack resistance of concrete in strong wind and high temperature weather.

Study on the Properties and Benefits of a Composite Separator Layer in Airport Cement Concrete Pavement

A composite separator layer in Portland cement concrete pavement, formed by a lower bearing layer and micro surfacing, was seldom used in airport pavement, but it has great application potential. This paper studied the properties of the composite separator layer and its benefits for pavement. The basic properties investigated in the study were resilient modulus and interlayer property between the separator layer and concrete. The resilient modulus of the micro surfacing was tested to calculate the modulus of the whole separation layer. The interlayer shearing test was done on core specimens using a self-developed facility that can apply load in the normal direction. Shearing test results show that temperature affects the shape of the shearing curve and normal stress linearly affects the stable shear force. Additionally, an in-situ erosion test was carried out to prove the anti-scouring property of the separator layer. Furthermore, a finite element model (FEM) model was established to study the influence of the composite separator layer. The FEM employed the modulus test results and the measured interlayer characteristic. The interlayer characteristic was simplified into a two-stage constitutional model. Monitored data on the mechanical response of the pavement structure in an airport validated the FEM model. Results show that the separator layer reduces the chance of contraction crack under the sudden temperature drop in the concrete slab before sawing. FEM results show that though the separator layer slightly increases the tensile stress of concrete, the tensile stress is greatly reduced if the slab develops voids in the future. The most significant benefit of the separation layer is it reduces the chance of void occurrence so that the lifespan of pavement with a separator layer is improved compared to regular pavements which frequently have voids beneath the slab. With the finite element model results and cumulative fatigue life equations, the separator layer was estimated to elongate the pavement service life for years, depending on the time voids appear.

Predicting the Remaining Service Life of Civil Airport Runway considering Reliability and Damage Accumulation

Based on the MEPDG method, the operation process of MEPDG was analyzed and the MEPDG correction method applied to the remaining life prediction of airport pavement was obtained. According to the theory of structural reliability, the performance function of airport pavement was obtained based on the limit state equation represented by flexural stress. Considering the characteristics of airport cement concrete pavement design, the calculation formula of the number of allowable load actions was obtained based on reliability by NCHRP126 fatigue equation without considering the temperature stress when the flexural fatigue strength of pavement plate cement concrete was less than 1.25 times of the design strength. Based on the actual situation of local civil airport runways in Henan Province, the proposed MEPDG correction method was used to analyze the flexural stress of the actual operating airport runway pavement at 95% reliability level based on the mechanical numerical model of airport runway, and the number of allowable load actions of three aircraft models was obtained. Given the impact of pass-to-coverage ratio P/C, the cumulative damage factor CDF of the major aircraft models was calculated; the annual average growth rate of different aircraft models in the airport pavement evaluation stage was obtained based on the trend extension method. According to the predicted average annual cumulative damage, the remaining life of pavement was predicted. Compared with the actual conditions of the airport, the remaining life predicted in this paper was consistent with the actual life, which verifies the effect of the prediction of the remaining life of airport runway considering the impact of reliability and damage accumulation.

Study of Structural Characteristics of Asphalt Overlays on Airport Pavement with Damaged Load Transfer Efficiency of Joints

In this paper, the real joint load transfer efficiency of airport pavement is calculated by combining the results of airport pavement deflection detection and ground-penetrating radar detection. Spring elements are used to simulate the actual load transfer efficiency of joints in ABAQUS. The impact of different asphalt overlays on the stress state of the critical point in the pavement is analyzed by the airport cement concrete pavement model. The result shows that adding a thin stress-absorbing layer with fine-graded and low modulus can effectively disperse the load transferred from the asphalt pavement to the cement pavement and the stress concentration at the joint under the asphalt overlay. Compared with airport pavement without a stress-absorbing layer, the tensile stress and shear stress at the critical point in the airport pavement asphalt overlay decreased by 24.62% and 22.49%, respectively. Therefore, the combination of the high-modulus upper layer and low-modulus lower layer can effectively reduce the tensile stress and shear stress at the critical point. In addition, increases in the thickness of the asphalt overlay can effectively improve the stress state at the critical point. When the thickness of the asphalt overlay changed from 13 cm to 21 cm, the maximum tensile and shear stress decreased by 8.82% and 8.92%, respectively. Finally, based on the analysis of the numerical simulation and field test verification, the optimal airport pavement asphalt overlay scheme is proposed.

Influence of steel pipe on mechanical properties of airport cement concrete pavement

This paper studies the influence of steel pipe on mechanical properties of airport cement concrete pavement. The flexural and compressive strength of concrete are analysed when different steel pipes are added into ordinary concrete. It is shown that the flexural and compressive strength of ordinary concrete are higher than those of concrete containing steel pipe at the age of 7 and 28 days. The compressive strength of concrete decreases more than the flexural strength when the steel pipe is added into concrete. The flexural strength of concrete containing Φ32 seamless steel pipe, DN32 welded steel pipe and DN40 welded steel pipe can still meet the mechanical properties of airport concrete. Compared with DN32 welded steel pipe and DN40 welded steel pipe, the selection of Φ32 seamless steel pipe is beneficial to the mechanical properties of concrete.

Research and Analysis of Civil Airport Cement Concrete Pavement Damage Condition Evaluation and Countermeasure

By investigating the civil airport cement concrete pavement conditions in different regions of China, this paper evaluates the damage condition and develops the main cause of some typical damages of airport pavement. In addition, this paper considers the ranking and previous solutions of some typical damages of airport pavement to provides suggestions to airport operators, organizers, and constructors regarding the timing, methodology, and investment decisions when dealing with airport runway damage.

Melting snow on airport cement concrete pavement with carbon fibre heating wires

In this paper, the method of melting snow with carbon fibre heating wires buried in airport cement concrete pavement is presented to avoid the adverse effects of snow-melting chemicals. The snow-melting experiment of pavement is conducted when the snow is heavy and the air temperature is from −4 to −3°C. Electrical power is supplied to the pavement through the use of carbon fibre heating wires. It is shown that, with an input power of 300 W m−2, the temperature of pavement surface can achieve an increment of 7.48°C and the 2.5 cm thick snow can be melted within 4 hours, which is just for melting snow at this condition. The temperature and energy distribution along the depth of pavement is analysed at different times. The findings indicate that the method of melting snow on airport pavement with carbon fibre heating wires is feasible in the snowy weather condition.

Design Countermeasures of Preventing Frost Heaving of the Airport Cement Concrete Pavement in Cold Area

In order to guarantee the design quality of the pavement in a cold area, by analyzing the nature conditions in the area, such a cold and long winter, short summer and high altitude, based on the reason of road frost damage, not only submit the design measure according to the basic performance requirements of structure of materials and the thickness of frost layer, but also submit the design measures according to provision of drainage system, isolated layers and blocking groundwater sources..

Automatically melting snow on airport cement concrete pavement with carbon fiber grille

In this paper, the method of melting snow with carbon fiber grille buried in airport pavement is presented to avoid the adverse effects of snow-melting chemicals on the structure, function, environment and safety. The outdoor snow-melting experiment of airport cement concrete pavement is conducted when the snow is heavy and the air temperature is from −3°C to −1°C. Electrical power is supplied to the airport pavement through the use of carbon fiber grille. It is shown that, with an input power of 350W/m2, the temperature of pavement surface can achieve an increment of 4.63°C and the 2.7cm thick snow can be melted within 2h, which is just for melting snow at this condition. After the heating stopped, the residual heat can melt snow on the pavement in real time when the temperature of pavement surface is kept above 0°C. The temperature and energy distribution along the depth of pavement are analyzed at different times. The findings indicate that the method of melting snow on airport pavement with carbon fiber grille is feasible in the snowy weather condition.

Testing Research on Application of Rapid-Hardening Sulphoaluminate Concrete in Rapid Repair Engineering for Airport Pavement

Aiming at rapid-repair engineering of airport cement concrete pavement, this paper chooses rapid-hardening sulphoaluminate cement to prepare rapid-hardening sulphoaluminate concrete (RSC) and evaluate its technology performance referring to test methods of Portland cement concrete. The testing results show that RSC possesses excellent workability, good mechanical properties along with abrasion resistance, little shrinkage, and strong bonding with old pavement, which can well meets the requirements of pavement rapid restoration under the condition of not closing airport.

Influence of the Dispensation of Transfer Bar to the Load Coefficient at Concrete Pavement Seam

The airport cement concrete pavement seam is very important to the bearing capacity and Flatness. Considering the importance of seams, a detailed three-dimensional finite element model was used to investigate the state of seams. According the calculation method of load transfer coefficient, the coefficient was obtained. Comparing the different coefficient, the best position of dowel steels, the best diameter of dowel steels, the best buried depth of dowel steels and the best joint width of dowel steels all can be gained best joint width of dowel steels all can be gained.

Performance and Utilization of Recycled Aggregates for Airport Cement Concrete Pavement

Cement concrete of airport pavement can be crushed into aggregates for recycle using, and the performance and utilizations of the recycled aggregates were discussed and researched herein. Sieve analysis indicated that the concrete should be crushed many times till the percentage of critical size (31.5mm) can satisfy the gradation requirements. Due to loss of crystal water, the density and water absorption of recycled aggregates were different from the natural ones, so that an empirical corretion equation was addressed subsequently. When the recycled aggregates used in the stablized base, theres no avilable method could yield the optimum water content, therefore a series of compaction and compression tests were employed to set up a modified design method. The results indicated the shrinkage property of recycled aggregates were susceptible to the moisture, either the skeleton-dense material structure and limiting the fine aggregates content were possible ways to eliminate the sensitivity. 7-day unconfined compressive strength results proved the recycled aggregates were suitble for the base course of heavy duty highways and airfield in grade E/F as well.

Application of WMA on Thin Overlay on Airport Cement Concrete Pavement

Considering the hot mix asphalt compaction quality is difficult to reach and it can be destroyed easily, the warm mix asphalt is used for thin overlay of airport cement concrete pavement. The mixture proportion of warm mix asphalt was designed, the performance of the base asphalt and the modified emulsify asphalt were measured, and the optimum asphalt quantity was determined, then the performance comparison between warm mix asphalt and hot mix asphalt were analyzed. Results indicate that warm mix asphalt has the same performance with hot mix asphalt, it can also satisfy the requirement of the airport cement concrete pavement thin overlay. Finally, in order to validate the project application effect, the warm mix asphalt was used in a northwest airport cement concrete pavement thin overlay. After four years use, the construction of the pavement is in good condition, and no disease emerging, the performance can meet the using requirements of the airport.