Applied Mechanics and Materials Vols. 638-640

Abstract: Make old cement concrete as recycled aggregate can not only protect environment, saving resources, but also can reduce the project cost, and promoting the sustainable development. This paper based on the related recycled concrete aggregate (RCA Recycled Concrete Aggregate) literature, mainly involve its properties, preparation and performance of RCA concrete, construction application etc..This has got a lot of reliable conclusions, so as to give some inspiration and help to the related scholars.

Abstract: Natural mineral fiber with good performances of mechanical properties and environmentally friendly, pollution-free especially have gradually aroused extensive concern. In order to improve the quality of asphalt pavement, explore the applicability of nature basalt fiber in enhanced asphalt mixture performance, this paper investigates two typical asphalt mixtures and contrastive studies pavement performance of asphalt mixture by high temperature stability, water stability, low temperature anti-cracking and fatigue performance between basalt fiber modified asphalt mixture and base asphalt mixture, and then study the basic principle of fiber reinforcing asphalt mixture. The research show that basalt fiber modified asphalt mixture has a better pavement performance than base asphalt mixture, its dynamic stability is 1.6 times than base asphalt mixture, low temperature anti-cracking performance increased by more 25% and fatigue life is more 2 times than base asphalt mixture. And the basalt fiber can be used in the road engineering as an additive material that enhances the comprehensive performance of asphalt pavement.

Abstract: In order to clear the slope geometry, surrounding soil parameters, sand filling parameter and other factors on the degree of influence of sand embankment slope stability, the sensitivity of the sand embankment slope stability influences factors was analyzed by using the orthogonality analysis method. The results show that the sequence of these influencing factors in terms of the influencing degree on the slope stability is embankment height > the friction angle of sand > the friction angle of surrounding soil > the cohesive strength of surrounding soil > slope gradient > the cohesive strength of sand > the bulk density of surrounding soil > thickness of surrounding soil > top layer thickness > the bulk density of sand. The embankment height, the friction angle of sand and the friction angle of surrounding soil are highly significant factors. The cohesive strength of surrounding soil, slope gradient and the cohesive strength of sand are significant factors.

Abstract: Temperature and load are the major factors of road surface deformation. This paper studies how the temperature causes the road surface deformation and what the deformation trend is. A simplified model of the pavement structure and double round load loading mode were adopted respectively to analyze the stress and strain changes of road surface result of the load and the coupling effect of temperature and load. The major conclusions drew on this study are: stiffness modulus of asphalt mixture attenuates rapidly as the temperature increases, and thereby results in a significant shear deformation of asphalt pavement. At the same temperature, compressive stress decreases with the increasing of load and the deepening of the pavement structure. The influence of coupling effect of temperature and load is more significant than a single temperature or load factor. Under different coupling effect of temperature and load circumstances, the pavement structure influenced mostly by the shear stress is located 3-9cm underneath the surface.

Abstract: To explore the effects of different factors on the rheological properties of cariphalte modified asphalt, based superpave asphalt binder relevant norms, through the use of dynamic shear rheometer Shell 70# asphalt under different temperature, frequency and strain conditions and rheological properties of cariphalte modified asphalt carrying on a systematic study, and comparative analysis of the two anti-fatigue properties of asphalt in the middle and low temperature.The results show that: compared with 70# asphalt, cariphalte modified asphalt has better rutting resistance over a wide temperature range; at lower frequencies and high intensity pavement, cariphalte modified asphalt to better resistance to permanent deformation; better fatigue resistance at low temperatures, and more fatigue damage is not easy to achieve.

Abstract: In the big cities, any construction nearby the metro structure become critical to the safety of the metro,especially for deep foundation pit engineering.In such case,Pile-anchor supporting system is normally used, however different deformation shape of the supporting wall will bring different deformation of the metro structure.This paper analysed the relations between the pile-anchor supporting system and the nearby metro structures and stated how to control the nearby metro structure deformation through the design of the Pile-anchor supporting system.The analysis showed the following conclusions:If the nearby metro structure is closer to the ground surface, it will be more sensitive to the deformation of the piles-anchor system;Shape 1 & 2 are better to control the metro structure deformation,Shape 3 will result bigger settlement;the metro structure above and in the middle of the foundation bottom level are very much influenced by the deformation of the piles;If the deformation of metro structure exceeds the allowable value, other measures should be considered.

Abstract: According to the critical factor of railway track geometric irregular, the deformations of track can be controlled. The lateral deviation is the key to determine the railway track irregularity. Currently, in the static inspected methods, the combined method of geodetic surveys and track surveying trolleys (inspecting instruments for static geometry parameter of track) is widely used in high-speed railway. Depending on some tests, the model of track irregularity in track surveying trolleys can be reconstructed by another method. According to the special features of track of high-speed railway, it is necessary to study on the accurate and effective lateral deviation algorithm which is suitable for the precise track inspection of high-speed railway. Based on some existing methods of construction layout in highway, the primary contents of this paper are: (1) reduces those methods to three algorithms, such as the Longitudinal Deviation Algorithm with Composite Simpson rule (LDACS), the Distance Function Algorithm of Newton’s method (DFAN) and Normal Perpendicular to Tangent Algorithm of Newton’s method (NPTAN), and (2) completes the algorithm steps of DFAN and NPTAN on circular curve, and proves the results of two algorithms on circular curve same, and (3) proposes the three algorithms to calculate lateral deviation and mileage of any rail detection points for inspecting the static geometric state of track in high-speed railway. Depending on some simulation data, the experimental results are: (1) the calculations of DFAN, NPTAN and LDACS, in which the number of subintervals of equal greater than or equal to five, meet the accuracy of the precise track detection of high-speed railway, and (2) the difference mileage and lateral deviation between DFAN and NPTAN are less than 0.001 mm, and (3) the efficiency of those algorithms is very considerable and the efficiency of DFAN is basically the same with NPTAN and higher than LDACS, and (4) the longer the transition curve is, the lower the efficiency and accuracy of DFAN and NPTAN are. The bigger the radius is, the higher the accuracy of LDACS is. According to the measurement data of the Chengdu Dujiangyan Railway Line (Cheng Guan Line), the above mentioned results of (1) and (2) can be proved correctly.

Abstract: According to the problem that the cohesiveness and durability of permeable asphalt pavement is poorer than common dense gradation asphalt mixtures, on the premise of improving the permeability, in order to meet the service performance and durability of permeable asphalt pavement, through the investigation of technical requirements on permeable asphalt pavement raw material in Japan and several endemic standards of China where permeable pavement technology is mature, combined with climatic characteristics in Tianjin, the technical requirements suggested values of permeable asphalt mixture suitable for Tianjin are put forward.

Abstract: Combined with practical examples of karst roadbed construction of Zhanghua highway, the article analyzes catastrophic manifestations, disaster causes and common prevention measures of karst collapse caused by roadbed construction; according to research putting forward the corresponding treatment program on engineering examples, engineering practice to good effect, showing that the proposed scheme of karst treatment is reasonable and reliable, referencing for similar projects.

Abstract: To get a grip on the influence of different factors on rheological properties of high modulus asphalt, the method of DSR measurement is made in a systematic study of different temperatures, loading frequency,strain 70^# base asphalt and rheological properties of high modulus asphalt. The experimental results show that high-modulus asphalt has a low sensitivity to temperature. Compared with the base asphalt, the high-modulus modified asphalt’s G*/sinδ will have a slower decrease under the condition of temperature increase. Both asphalt’s G*/sinδ would decrease with the decrease of load frequency, high-modulus asphalt has a higher G*/sinδ than base asphalt especially at the higher temperature and lower frequency.