Loading Stress Analysis of Cement Concrete Pavement in Mountainous Areas

The suitable cement concrete pavement for mountainous areas is a form of low-cost cement concrete pavement that uses unconventional graded stones in different proportions in ordinary concrete,allowing the concrete to fully contact the stones and form a stable and well-bonded slab with large particle stones.As large particle stones replace a certain volume of cement concrete,they have good economic performance and are a low-cost form of cement concrete pavement.This study researches the use of ANSYS tools to analyze the influence of geometric dimensions and material properties of rigid pavement structural layers on the mechanical properties of pavement structures.

Study on the Design Criteria for Prestressed Concrete Pavements

With a concrete pavement slab prestressed, its load carrying capacity can be significantly increased; thus a thinner slab may be used for the same loading. Prestressing modify the structural behavior of the pavement slab and there is a greater resistance to impact, vibration and overloading. This paper discusses the major design considerations necessary in the successful construction of prestressed concrete pavements and presents a design procedure developed to predict the compressive stress due to prestressing in the pavements at early stage, during service and after cracking. Variation in the approach for repetitive and nonrepetitive loads is clearly distinguished. Check on the recovery after cracking for overloading in prestressed pavements is also needed. Finally, a design example is illustrated the application of the approach developed.

Characterizing properties of magnesium oxychloride cement concrete pavement

The performance of magnesium oxychloride cement concrete(MOCC)in road engineering in the arid region in northwest China was investigated over a two-year period.Two categories of MOCC pavement,light-burnt magnesia concrete road(Road-L)and dolomite concrete road(Road-D),were prepared with light-burnt magnesia and a mixture of light-burnt magnesia and caustic dolomite(1:3 by mass),respectively.Variations in the properties of the MOCC pavement,such as compressive and flexural strength,mineralogical phase,and microstructure,after being exposed to two rainy seasons in the field were monitored.The compressive strength of the cored samples were conducted after being aged for 28 d,and the compressive and flexural strength were tested at ages of 1,2,3,28,90,180,270,360 and 720 d.The mineralogical phase and microstructure of the pavement were also analyzed by X-ray diffraction(XRD)and scanning electron microscopy(SEM).The results demonstrate that MOCC pavement obtained desirable compressive and flexural strengths after curing for 3 d for Road-L and 28 d for Road-D.Both of the compressive and flexural strength of Road-L and Road-D decreased slightly after experiencing two rainy seasons,with the major hydration products being 5Mg(OH)2 MgCl28H2O(Phase 5)and 3Mg(OH)2 MgCl28H2O(Phase 3).The decomposition of Phase 5 is mainly responsible for reducing the mechanical strength of the MOCC pavement.

Causes and Treatment Measures of Rural Highway Concrete Pavement Damages in Mountainous Area

Combined with the practical experience in constructing and maintenance managing the concrete pavement damage repair of Gaotang-Nenghuashan forest highway of Jiangle County,the common damage types and causes of rural highway concrete pavement in the northwestern mountainous area of Western Fujian Province were analyzed,and corresponding treatment measures to various damage were put forward.

Toughness improvement mechanism and evaluation of cement concrete for road pavement:A review

Traditional cement concrete has the disadvantages of low tensile strength,poor toughness,and rapid development of cracks while cracking,which causes a significantly negative influence on the safety and durability of concrete road pavement.This paper presents a state-of-the-art review of toughness improvement mechanisms and evaluation methods of cement concrete for road pavement.The review indicates that(i)The performance of concrete material depends on its material composition and internal structure.Aggregate size,cement properties and admixtures are the main factors of concrete toughness.(ii)The incorporation of rubber or fiber in pavement concrete improves the toughness of concrete materials.However,these additions must be maintained within a reasonable range.The amount of rubber and fiber are encouraged not more than 30%of the volume of fine aggregate and 2%of the volume of concrete,respectively.(iii)The toughness of pavement concrete material includes the toughness regarding bending,impact and fracture.The toughness of cement concrete for highway and municipal pavement is generally evaluated by bending and fracture toughness,while the toughness of airfield pavement concrete is more focused on impact toughness.(iv)The toughening measures of cement concrete for road pavement are mainly mixed with rubber or fiber,while these two materials have their defects,and the application of hightoughness cement concrete in the actual road still faces many challenges.For example,the synergistic effect of rubber and fiber,the development and application of new flexible admixtures,and the formulation of the toughness index of pavement cement concrete materials need further research.

Texturing and evaluation of concrete pavement surface:A state-of-the-art review

Concrete pavement is accompanied by two major functional properties,namely noise emission and friction,which are closely related to pavement surface texture.While several technologies have been developed to mitigate tirepavement noise and improve driving friction by surface texturization,limited information is available to compare the advantages and disadvantages of different surface textures.In this study,a state-of-the-art and state-of-thepractice review is conducted to investigate the noise reduction and friction improvement technologies for concrete pavement surfaces.The commonly used tests for characterizing the surface texture,skid resistance,and noise emission of concrete pavement were first summarized.Then,the texturing methods for both fresh and hardened concrete pavement surfaces were discussed,and the friction,noise emission and durability performances of various surface textures were compared.It is found that the next generation concrete surface(NGCS)texture generally provides the best noise emission performance and excellent friction properties.The exposed aggregate concrete(EAC)and optimized diamond grinding textures are also promising alternatives.Lastly,the technical parameters for the application of both diamond grinding and diamond grinding&grooving textures were recommended based on the authors'research and practical experience in Germany and the US.This study offers a convenient reference to the pavement researchers and engineers who seek to quickly understand relevant knowledge and choose the most appropriate surface textures for concrete pavements.

Multi-gene genetic programming extension of AASHTO M-E for design oflow-volume concrete pavements

The American Association of State Highway and Transportation Officials Mechanistic-Empirical Pavement DesignGuide (AASHTO M-E) offers an opportunity to design more economical and sustainable high-volume rigid pavementscompared to conventional design guidelines. It is achieved through optimizing pavement structural andthickness design under specified climate and traffic conditions using advanced M-E principles, thereby minimizingeconomic costs and environmental impact. However, the implementation of AASHTO M-E design for low-volumeconcrete pavements using AASHTOWare Pavement ME Design (Pavement ME) software is often overly conservative.This is because Pavement ME specifies the minimum design thickness of concrete slab as 152.4 mm (6 in.). Thispaper introduces a novel extension of the AASHTO M-E framework for the design of low-volume joint plain concretepavements (JPCPs) without modification of Pavement ME. It utilizes multi-gene genetic programming (MGGP)-based computational models to obtain rapid solutions for JPCP damage accumulation and long-term performanceanalyses. The developed MGGP models simulate the fatigue damage and differential energy accumulations. Thispermits the prediction of transverse cracking and joint faulting for a wide range of design input parameters and axlespectrum. The developed MGGP-based models match Pavement ME-predicted cracking and faulting for rigidpavements with conventional concrete slab thicknesses and enable rational extrapolation of performance predictionfor thinner JPCPs. This paper demonstrates how the developed computational model enables sustainable lowvolumepavement design using optimized ME solutions for Pittsburgh, PA, conditions.

Study on Performances of the Concrete Pavement from Zincilate

The use of zincilate production of concrete pavement brick both use of industrial solid waste, protect the environment and promoting building energy efficiency, there are huge comprehensive benefits. Based on the guizhou bijie zincilate as the main raw material preparation from concrete pavement brick, and the main factors which influence the quality of the products was investigated. The test results show that: Concrete pavement brick compressive strength at 28 days with zinc slag volume increases, zinc slag admixture is 40%, 28 days compressive strength is more than 32 MPa.

Cracking and Mechanical Properties of Airport Concrete Pavement with Fiber and Expansive Agent

Polypropylene fiber and expansive agent are used in airport concrete to improve its shrinkage cracking resistance and mechanical properties.The concrete specimens with amount content of polypropylene fiber or expansive agent or both of them are prepared.The morphology of specimens is observed by scanning electron microscope,the time when the first crack occurred is recorded through slap test,and the mechanical properties such as compressive strength and impact energies of concrete are measured.The results show that polypropylene fiber in concrete can reduce the shrinkage and delay the first crack,improve the impact resistance obviously,and improve the compressive strength slightly.Expansive agent can compensate the shrinkage and reduce cracks of concrete pavement markedly,and improve the mechanical properties of concrete pavement slightly.The study provides recommendations for cracking control of airport concrete pavement in the future.

In-site health monitoring of cement concrete pavements based on optical fiber sensing technology

Premature stress of cement concrete pavements i the coupled action of construction technique,structural ma-terial and environmental action.It is quite diffiault to accurately get the actual stress distribution merely based on the theoretical or simulation analysis.Ther efore,in-situ health monitoring is particularly si gnificant to obtain the stress or strain information for the assessment on structural perfor mance of cement concrete pavements.To contribute this topic,different kinds of FBG based sensors have been specially designed to measure the tem-perature,pressure and deformation in cement concrete pavements.A relatively long-term monitoring has been aonducted to collect the effective data after the solidification of the pavement lasts for about 15 d.Data analysis indicates that the temperature variation inside the pavement was very stable,with maximum ampltude smaller than 2.25°C in Sep.2020.The longitudinal,transverse and ver tical deformations of the pavement behaved in non-umniform distribution,and partial me asuring points suffered from large tensile force.The concrete course had better deformation resi stance than that of the soil base,and local interfacial micro void defects existed in the soil base.The preliminary results can help to understand the actual structural performance of cement concrete pavements based on the optical fiber sensing sys tem.

Usability of Waste Steel Grits in Concrete Pavement

The usability of waste steel grits and limestone sand in the construction of concrete pavement was investigated.Four different types of pavement concretes were produced,including coarse limestone concrete not containing waste steel grit,coarse limestone concrete containing waste steel grit,limestone sand concrete not containing waste steel grit,and limestone sand concrete containing waste steel grit.In this study,water/binder ratio in concrete production was taken as 0.44.In the production of limestone sand concrete containing waste steel grit,limestone sand with a grain diameter of 0.1-1.0 mm was used as aggregate.Waste steel grits with a grain diameter of 0.2-0.7 mm were added to the concrete mixture.Standard water curing and combined curing were applied to concrete samples.After standard water curing and combined curing,compression and bending tests of the same types of cube and beam concrete samples were carried out.As a result of the study,the maximum compressive and bending strengths were found to be 50.21 MPa and 5.07 MPa for limestone sand concrete containing waste steel grit.The study results show that waste steel grits increase the compressive and bending strength of concrete pavement.

Concrete Containing Marginal Aggregates for Use in Concrete Pavement

The study presented an analysis accessing the feasibility of using concrete containing marginal aggregates in concrete pavement slabs. The physical properties of aggregates were first determined and concrete was produced from them. Marginal aggregates were found to have higher fines, absorption, soundness loss, micro-Deval abrasion loss, LA （Los Angeles） abrasion loss and lower specific gravity and unit weight when compared with standard aggregates. Workability of concrete containing marginal aggregate was found to be similar to concrete containing normal aggregates when Shilstone mix design method was used to optimize the concrete mixes. The compressive strength, splitting tensile, flexural strength and modulus of elasticity of concrete containing marginal aggregates were determined and found to be generally lower than concrete containing standard aggregates. A typical concrete pavement in Florida was modeled in FEACONSIV （finite element analysis of concrete slab） software developed at the University of Florida. Laboratory determined mechanical and thermal properties of concrete were inputted in FEACONS IV and analyzed for maximum induced stresses. Critical stress to strength ratios, i.e., ratio between maximum computed stresses obtained from FEACONS IV to modulus of rupture （strength） of concrete, was used as evaluation criterion for different concrete pavement mixes. It was found that, in general, concrete containing marginal aggregates have higher stress to strength ratios as compared with concrete containing standard aggregates.

Constraints in Using Manufactured Sands in Concrete Pavements in Australia

Due to the shortages of natural sands along the east coast of Australia in particular and the need to fully utilise fines produced in quarry operations, progress has been made in utilising blends of manufactured sands and natural sands in concrete pavements. This paper documents some of the constraints in utilising larger proportions of manufactured sands in concrete pavements. These constraints are mainly caused by the current level of knowledge regarding the impact of manufactured sands on skid and abrasion resistance of concrete pavements. This paper presents a brief review of literature on this subject in the USA, France and UK. It also briefly documents work recently carried out in Australia by CCAA （Cement Concrete and Aggregates Australia）, referring to the skid and abrasion resistance of concrete pavements using manufactured sands. The paper concludes that there is no relationship between the free silica content and the skid resistance. With regard to the abrasion resistance, it is rather the curing conditions and the compressive strength that are more important in achieving good results.

INFLUENCE OF AIRCRAFT DEICER ON FREEZE-THAW DURABILITY OF HIGH PERFORMANCE CONCRETE

The influence of glycol,the main composition of the most frequently used aircraft dicer,on the freeze-thaw durability of high performance concrete（HPC）is investigated.Freeze-thaw durability of HPC is tested by accelerated freeze-thaw test.Four kinds of the solution,i.e.,tap water,3.5% NaCl solution,glycol solutions,and a LBR-A type commercial aircraft deicer are employed.Results show that freeze-thaw durability of HPC exposed to glycol solutions is closely related to the solution concentrations.The failure of HPC exposed to 3.5% glycol solution is similar to that of those exposed to 3.5% NaCl solution,i.e.,serious surface scaling.While the damage of HPC exposed to 12.5%—25% glycol solutions is postponed.Compared with glycol solution,the commercial aircraft deicer has much more negative effects on HPC freeze-thaw durability compared with 3.5% NaCl solution.In the presence of commercial aircraft deicer for HPC subjected to freeze-thaw cycles,the deterioration is mainly due to scaling and spalling.

Pervious Concrete as an Alternative for Non-structural Drainage to the Amazon Region:From Properties to Applications in Watersheds

The urbanization process of the urban centers in the Amazon occurred quickly and without planning. Belém, one of the main cities in the region, suffers from intense flooding due to urbanization growth and the disorderly occupation of floodplains. The objective was to evaluate the producing of pervious concrete that meets the mechanical and hydraulic performance criteria for permeable pavement molded on site and to simulate the replacement of the entire public walkway system of a hydrographic basin in Belém in order to verify if this measure would alter the permeability of the basin and meet minimum requirements of at least 25% permeable area. The properties of three mixtures of pervious concrete with aggregates of different grading were evaluated. The permeability and flexural strength of all blends were higher than the minimum required for use as a permeable pavement for light vehicle traffic. The simulation showed that replacement of the public walkway by permeable pavement increased the permeable area of the watershed from 19 to 23%, changing from a poor condition to an acceptable level. The results indicate the potential to improve the performance of drainage systems through the wider use of permeable pavement associated with traditional structural measures.

Study of interfacial transition zones between magnesium phosphate cement and Portland cement concrete pavement

The Portland cement concrete pavement(PCCP)often suffers from different environmental distresses and vehicle load failure,resulting in slab corner fractures,potholes,and other diseases.Rapid repair has become one of the effective ways to open traffic rapidly.In this study,a novel type of rapid repair material,basalt fiber reinforced polymer modified magnesium phosphate cement(BFPMPC),is used to rapidly repair PCCP.Notably,the mechanical properties and characteristics of the repair interfaces which are named interfacial transition zones(ITZs)formed by BFPMPC and cement concrete are focused on as a decisive factor for the performance of the rapid repair.The changing trend of the elastic moduli was studied by nanoindentation experiments in the ITZs with the deconvolution analysis that the elastic moduli of certain kinds of substances can be determined.The experimental results show that the elastic modulus of ITZ-1 with a width of about20μm can be regarded as 0.098 times of the aggregate,and 0.51 times of the ordinary Portland cement(OPC)mortar.The BFPMPC-OPC mortar ITZ has roughly the same mechanical properties as the ITZ between aggregate and BFPMPC.A multi-scale representative two-dimensional model was established by random aggregate and a two-dimensional extended finite element method(XFEM)to study the mechanical properties of the repair interface.The simulation results show that the ITZ formed by the interface of BFPMPC and OPC mortar and basalt aggregate is the most vulnerable to failure,which is consistent with the nano-indentation experimental results.

Research on the Evaluation System of Epoxy Asphalt Steel Deck Pavement Distress Condition

Epoxy asphalt concrete has been one of the mainstream technology of steel deck pavement in China. But little specification about evaluation system for its distress condition has been researched and maintenance was still unsystematic. The section weight coefficient of different distress is proposed by analyzing the applicability of the “Highway Performance Assessment Standards”. Indexes mainly including SDPCI PDR and PCR are presented to evaluate its distress condition. The evaluation system and maintenance plan decision tree were recommended which can assist scientific maintenance of epoxy asphalt steel deck pavement.

Fatigue damage analysis of epoxy asphalt pavement for steel bridges considering coupled effects of heavy load and temperature variations

To investigate the fatigue damage of epoxy asphalt pavement(EAP)under a heavy load and a d temperature load,the load-figure of the heavy load on the steel bridge deck pavement(SBDP)was simulated first,and the temperature distribution of SBDP during the temperature-fall period in winter was also calculated.Secondly,t e moving heavy load coupled W t the most unfavorable temperatre load was applied to the SBDP,and the tensile stress on the top of SBDP was calculated.Finally,the fatigue damage of EAP was evaluated considering the extreme situation of heavily overloaded and severe environments.The results show that botte heavy load and the temperature load during t e temperature-fall period c n increase the tensile stress on the top of SBDP significantly.In the exteme situation of heavily overloaded and severe environments,a fatigue crack is easily generated,and thus the SBDP should avoid t e coupling effects of the heavy loadand the temperature load in winter.

Control of Pavement-Surface Temperature-Rise Using Recycled Materials

High temperatures of the asphalt concrete pavements in summer contribute to the heat island phenomenon in the urban areas. The effective cool-pavement technologies are sought to mitigate the pavement environment. In this paper, developed heat-reflective pavements are constructed from open-graded asphalt concrete, in which voids in the upper part of the pavement are filled with a cement mortar, containing recycled materials as a fine aggregate. The recycled materials used in this study are： crushed oyster shells, roof tile debris, pottery debris, glass cullet, crushed escallops and coral sand. The temperature reduction of the pavement surfaces at an open site is measured in the summer. The results show that the maximum surface temperature of the pavements falls by approximately 8-10 ℃ compared to the asphalt concrete pavement. Furthermore, it is found that the temperature reduction is mainly due to the increased solar radiation reflectance of the pavement surface.

Rubblization: A Practical, Cost Effective and Sustainable Option for Repairing Deteriorated Airfield Pavement in the Empty Quarter Desert of Saudi Arabia

Rubblization technique has been extensively used to repair the damaged concrete pavement and has proven successful in developed countries like the US and Europe. It has not been fully adopted in developing region like the Middle East and this paper presents the design and construction challenges posed while assessing damaged concrete runway in empty quarter of Saudi Arabia. A number of design options for repairs for runway pavement were considered and rubblization was chosen as a preferred option for repair. This paper includes the consideration for the assessment and adoption of the concrete rubblized modulus value using the falling weight deflectometer, optimization of the tests for the whole runway using the Heavy Weight Deflectometer HWD testing to replace pits, safely working around the utilities, reasonable assumption of drop height of the pavement and installation of utility conduits in the rubblized layer. Findings of the paper demonstrates resolving technical issues which are not very well covered in the Federal Aviation Authority (FAA) EB-66 such as the additional test strips, minimum areas of rubblization for assessment using test pits, drop in the height of concrete surface and fixing of utilities in rubblized pavement. The case study demonstrates that the rubblization can be successfully carried out in remote locations like empty quarter of Saudi Arabia with carefully carried out detailed site investigations, adopting correct assumed design rubblization modulus, quality control using HWD, protection of utilities while rubblizing and use of polymer modified asphalt for successful project deployment.