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11.
介绍了用工控组态软件“组态王”建立和访问沥青拌和楼控制系统的数据库,利用工控软件的数据库接口和Windows98操作系统的ODBC数据源,通过SQL对Access数据库进行操作。 相似文献
12.
该文基于有限元软件,通过耦合气候温度和太阳辐射,使用连续变温方法分别计算车辙问题。通过研究发现沥青路面的车辙变形规律与温度场分布规律相近,主要是沥青路面与轮胎之间的剪切变形不断积累最终导致车辙的形成。 相似文献
13.
以临长高速公路就地热再生工程为依托,简述了就地热再生技术的施工流程,阐述了原沥青路面混合料试验、沥青掺加再生剂试验要点,并通过再生混合料施工配合比设计,总结了施工过程中的质量控制措施。 相似文献
14.
采用动态剪切流变仪(DSR)对一定的实验温度(160℃)下加入分乳液再生剂a1和油液再生剂a2的老化沥青胶浆的流变学性能进行了评价。结果表明:分别加入两种再生剂后,老化沥青的流变性发生显著变化,a1再生剂的再生效果与其本身含水量有关,a2再生剂的再生效果较好。 相似文献
15.
《International Journal of Pavement Engineering》2012,13(4):215-222
A broken and seated portland cement concrete pavement (PCCP) was analyzed using destructive and nondestructive testing (NDT). The paper focuses on the results of a series of NDT methodologies by which the effective structural capacity of the overlaid pavement was estimated. The NDT included Falling Weight Deflectometer (FWD) and Road Rater (RR), followed by back-calculation and verification routines. A comparison was performed between the FWD and RR deflection bowls, which demonstrated a close correspondence between the two NDT devices. The effective modulus of the broken and seated PCCP was estimated and it showed close agreement with previous work conducted by other investigators, A large-stone hot mix asphalt (HMA) overlay was placed on top of the broken and seated PCCP; this decision was made based upon rutting resistance of this type of mix as reported in previous studies. 相似文献
16.
《International Journal of Pavement Engineering》2012,13(2):119-132
The paper describes an investigation on fatigue of Asphalt Concrete modified by addition of crumb rubber as a pan of aggregates. Flexural fatigue tests on Asphalt Concrete and Rubber Modified Asphalt Concrete conducted at 20. 25 and 30°C under constant strain mode indicated that the fatigue life of Rubber Modified Asphalt Concrete is significantly higher than that of the plain Asphalt Concrete. Design charts are presented to show that the pavement with Rubber Modified Asphalt Concrete requires a lower design thickness. 相似文献
17.
《International Journal of Pavement Engineering》2012,13(4):229-240
This paper documents and discusses an investigation into the time–temperature superposition principle as it relates to ductile failure in asphalt. Seven binders of approximately the same low and intermediate temperature and varying high temperature Superpave® grades were tested in a dynamic shear rheometer (DSR) and double-edge-notched tension test to determine their rheological and failure energy master curves. Master curves typically permit the prediction of rheological properties at very long or short timescales from measurements at higher or lower test temperatures over more accessible testing timescales. It has been suggested in the Strategic Highway Research Program final report A-369 that rheological shift factors obtained from a DSR experiment can be used to predict failure master curves from experimentally accessible data at various temperatures. The findings of this study suggest that this substitution is not generally accurate. For straight asphalt binders the difference can be relatively small but for more highly modified materials serious errors would be introduced. 相似文献
18.
《International Journal of Pavement Engineering》2012,13(6):389-399
The presence of moisture in asphalt pavements detrimentally affects the bond between the aggregate and binder and the bond within the binder. The loss of these bonds leads to the deterioration of asphalt pavements. In regions with low rainfall, moisture diffusion is an important source of moisture transport in asphalt mixtures. The diffusion coefficient is a necessary input for models simulating moisture transport and, consequently, moisture damage in asphalt pavements. In this study, an experimental protocol was developed for determining the moisture diffusion coefficient of asphalt mixtures. The experimental set-up relies on measuring suction over time in test specimens using thermocouple psychrometers. The proposed protocol successfully determined a wide range of diffusion coefficients (i.e. from 5.67 × 10− 5 to 2.92 × 10− 6 cm2/s) of different asphalt mixtures. X-ray computed tomography was used to characterise the air void structure of test specimens. The results revealed good correlation between the diffusion coefficient value and the per cent of air voids and the average radius of air voids in the test specimens. The diffusion coefficient values determined in this study can be used as an input in models for determining the rate of moisture diffusion in asphalt mixtures with different per cents of air voids. 相似文献
19.
《International Journal of Pavement Engineering》2012,13(2):87-100
A new image analysis program is presented to determine morphological and textural properties of aggregates, asphalt binder and air voids in compacted asphalt mixes. The procedure involves scanning cut sections of laboratory or field specimens and estimating volumetric properties based on a pseudo 3D algorithm. Properties that are calculated include gradation, asphalt content, air void content, amount of flat/elongated particles, distribution of particle orientations, air void profiles, and various particle shape and textural measures. Validation of the code for specimens for which reference values were available indicates generally good predictions, particularly with regard to gradation and asphalt content. The objective of the study has been to develop a robust procedure that is easy to use, cost efficient, environmentally friendly and that can be used as a means to determine asphalt characteristics for quality control and quality assurance purposes. The new analysis technique may also find application in the study of SEM resin-impregnated soil thin sections and concrete cross sections. 相似文献
20.
《International Journal of Pavement Engineering》2012,13(5):355-364
Fatigue and rutting equations are essentially used in design of asphalt pavements by mechanistic-empirical method and they are developed from the laboratory and/or the field performance data. Conventionally, ordinary least square regression analysis is employed for developing these equations. The present paper discusses the underlying assumptions of ordinary least square regression analysis and shows that these assumptions are violated while developing fatigue/rutting equations from the data obtained from field or laboratory measurements. This paper proposes the use of a measurement error based estimator in order to alleviate the inaccuracy associated with use of least square regression analysis while developing fatigue and rutting equations. A step-by-step methodology is presented on how to develop the fatigue or rutting equation from a given data set using the proposed method. The confidence intervals of the estimators are obtained using bootstraping technique. Finally, a design example is presented to show the differences in design thickness values obtained by the conventional and the proposed method. 相似文献