Advanced Materials Research Vol. 723

Abstract: This paper summaries the characteristic of French high modulus asphalt mixture (EME2), does a full set of performance evaluation through French test methods specified in LPC Bituminous Mixtures Design Guide and current test methods in China, and puts forward the preliminary recommendation of French high modulus asphalt mixture (EME2) application in China. It will provide technical reference to help to develop market of the French high modulus asphalt mixture (EME2) application in China and propose a new road building material for the construction of our highway.

Abstract: Pervious concrete is a relatively new material, standards and rigorous specifications for construction and placement are therefore still missing. One the one hand, the main characteristic to achieve is a high permeability to allow meteoric water percolate in the pavement and evaporate from the subgrade. On the other hand, developing pavement cementitious mixtures able to retain high void contents and reach significant mechanical performance entails an in-depth analysis of materials and construction practices. Pervious concrete can indeed be placed using a standard paver as for asphalt mixtures but the compaction stage is usually demanded to the contractor practices: light steel hand-rollers or standard drum rollers are both used without an in-depth knowledge of compaction properties of the cementitious mixture. The present paper aims at investigating the influence of compaction methods on the mechanical performance and void contents of pervious concrete mixtures. Several compaction procedures were tested modifying the compaction energy and the mixture characteristics while preserving high permeability. The main objective was to simulate and identify the effect of commonly adopted in situ compaction techniques - i.e.: tamper compaction as provided by the paver, steel hand-roller compaction, or standard drum roller compaction. Results showed how the compaction energy, water/cement ratios, and the percentage of cement affect the Indirect Tensile Strength and void contents of the mixtures. Further investigations were also conducted in order to comprehensively evaluate how the variation in the percentage of cement and water/cement ratio influenced the stiffness of the material.

Abstract: This work addresses the comprehensive viscosity measurements and assessment of fluidic materials in the range from 0.01 to 2000 Poises using a fiber optical viscometer with the long-period fiber grating (LPFG) technology. The fluidic materials used and evaluated in this study were AC-20 asphalt cement, four types of silicone oils, and sunflower seed oil. We simultaneously measured the LPFG-induced discharge time and the transmission spectra both in hot air and fluidic materials (other than the AC-20 asphalt) at six different temperatures, i.e., 30, 60, 80, 100, 135, and 170 Celsius. An electromechanical rotational viscometer was also used to measure the viscosities of fluidic materialsthe silicone oils and sunflower seed oil at the above six temperatures. Comparative analysis shows that the LPFG-induced discharge time agreed well with the viscosities obtained from the rotational viscometer. The LPFG-based viscometer was capable of measuring the viscosity (discharge time) in the range from 0.12 to 2000 Poises, which is much wider than the viscosity range of a traditional electromechanical rotational viscometer. This fiber-optic LPFG-based viscometer could be proposed and implemented in the field of road and airfield pavement technology such as the viscosity measurements of asphalt cements, emulsified asphalt binders, and other viscous materials. Hopefully, such a highly sensitive viscometer is suitable for use in various fields of applications, such as civil, food, chemical and biological, mechanical, petroleum, and aerospace engineering.

Abstract: The measurement of dielectric response has gained importance because it can be used for non-destructive monitoring of asphalt pavements. The open-ended coaxial probe technique was selected to investigate the dielectric response of the dense-graded asphalt mixture. The effects of material properties such as density on dielectric response were examined. Results indicated that density have a significant influence on dielectric behavior of asphalt mixture. The dielectric constant was shown to increase with increasing density of the asphalt mixture, whereas a high density resulted in low voids that contributed to a relatively high dielectric constant. These findings could be used to enhance the accuracy of non-destructive electromagnetic devices applied in the pavement field.

Abstract: The use of deep strength asphalt materials characterization to construct and restore the heavily urban roads where damage has been induced is rapidly grown in Western Australia. Five different types of asphalt mixes were produced in laboratory to modify pavement performance mixture. The main role of this research is to evaluate the pavement materials characterization for Western Australia road. In this study, laboratory test for tensile strength, resilient modulus, wheel tracking, binder contents, Marshall Compaction, and air voids contents test were taken to analyze each asphalt mixtures. The results indicated that AC20-75 and AC14-75 asphalt mixes blow were in a good pavement performance as compared to other asphalt mixes. For a mix design purposed, all the asphalt mixes that are used in this study can strength and stable the stiffness of pavement that is notable, and the modification effect rank can be described as AC20-75 Blow > AC14-75 Blow > AC14-50 Blow > AC7-50 Blow > SMA7-50 Blow in this research.

Abstract: The study presents the comparative evaluation of mixture performance of the Superpave and dense-graded mixtures using the results of repeated shear test at constant height (RSCH), frequency sweep test at constant height (FSCH), and Hamburg wheel-tracking device (HWTD) test. The results of HWTD testing displayed the Superpave mixtures I and II were less susceptible to permanent deformation than the dense-graded mixture. The results of RSCH testing showed the cumulative shear strain and the predicted rut depths of the accumulated shear strain of the dense-graded mixture was about six times as large as those of the Superpave mixtures I and II. Compared with the test results of HWTD testing, the Superpave mixture II was less susceptible to permanent deformation and the dense-grade mixture was the most prone to rutting among these three mixtures. The normalizing frequency parameter of the dense-graded mixture was about one and half to five times as large as those of the Superpave mixtures I and II. The larger value the specification parameternormalizing frequency parameter, the less that the mixtures could exhibit performance ranking. The use of specification parameter obtained from FSCH test, normalizing frequency parameter, for assessing mixture performance was consistent with the findings from HWTD and RSCH tests. Therefore, the Superpave mixture II ranked first and the dense-graded mixture ranked third based on the overall mixture performance.

Abstract: The concrete as surface pavement is more durable than asphalt pavement, while requiring less maintenance and having longer life. This paper discusses about the benefits of rigid pavements utilizing steel fiber upon receiving vehicle load. The study aims to improve the performance of concrete used as rigid pavement with 0.5 water/cement ratio by adding hook-shaped steel fibers. In this study, the amount of steel fiber varied, ranging from 0 to 15% based on trial and error. The hook-shaped fibers used were manufactured from steel in factory. Performance of samples were conducted in laboratory on fresh and hardened concrete behavior, including flexural strength and flexural toughness. Results showed that all of the assessed concrete performance increased as fiber was added, and the greatest value was obtained with nine percent of fibers.

Abstract: As for the existing surface energy adhesion theories which are used to evaluate asphalt and stone's adhesive performance quantitatively, they are either dealing with the interface between solid asphalt and solid stone which can not adhere according to the formulas and definitions in process of adhesion or else roughly characterizing the solid asphalt and stone's adhesion properties with the adhesion index of heated asphalt and solid stone. So according to the forming process of asphalt mixture , this paper puts forward the method and principle to evaluate asphalt and stone's adhesion based on the surface energy theory. It evaluates the adhesion properties of asphalt and stone under hydrous and anhydrous conditions respectively. In the anhydrous condition, we choose contact angle and the Gibbs free energy of failure stage as the indexes of evaluating asphalt - stone interface's adhesion properties, while the materials under the hydrous condition, we select cohesional work, contact angle, Gibbs free energy as the indexes of evaluating asphalt-stone system's resistance of moisture.

Abstract: This study focused on the properties of the cement asphalt emulsion (CA) mortar. The mixtures of the samples were fabricated and allowed them seven, fourteen and twenty eight days for curing before tested by compressive strength, three points flexural test, and indirect tensile strength to probe into their engineering properties. Hydraulic cement mortar samples used as control are analyzed for comparison. The test results show that the compressive strength is hydraulic cement mortar greater than CA mortar; the flexural strength at curing of 28 days is CA mortar greater than hydraulic cement mortar, however, at curing of 7 and 14 days is hydraulic cement mortar greater than CA mortar; and the indirect tensile strength is hydraulic cement mortar greater than CA mortar. The Scanning Electron Microscope (SEM) analysis results show that the Ca (OH₂) increased with increases curing time. The CA mortar samples fabricated needs appropriate water for lubrication. Thus, the water absorption of fine aggregate must be concerned. The emulsion asphalt added too much may reduce the strength. In field test, the CA mortar performs very well, especially in workability.

Abstract: This study investigated the influence of crystalline sealers and curing environment on compressive strength, splitting strength and elastic modulus of cement-based composites. Four kinds of crystalline sealers addition (0 %, 3 %, 5 % and 7 %) were used in the concrete specimens. SEM observations were assisted in verifying the results of mechanical properties. The test results demonstrated that the specimens increased the mechanical properties with the inclusion of crystalline sealers increased. The crystalline sealers reacted with cement to produce the crystals and hydrations, which could fill with the pore and supply a denser microstructure. This appearance was verified by the SEM micrographs. In inclusion, the cement-based composites containing 7 % crystalline sealers seem to give superior mechanical properties, and make the pores become finer and enhance the durability.