Wang Q.Z.,Hebei University of Technology |
Liu S.Y.,Tianjin Municipal Engineering Research Institute |
Li X.L.,Tianjin Municipal Engineering Research Institute
Applied Mechanics and Materials | Year: 2013
The warm mix asphalt technology was introduced to breaks through the low reclaimed asphalt pavement(RAP) ratio in central plant hot recycled engineering. Firstly, performance tests for traditional hot mix asphalt and central plant warm recycled asphalt mixture with different RAP ratios (0%,40%,50%,70%,100%)were conducted. It was concluded that the performance of warm mix asphalt was as good as hot mix asphalt, and the RAP ratio could increase to 60% by central plant warm recycling technology. Then a practical central plant warm recycled engineering with RAP ratio 50% was analyzed. It was concluded that not only the performance of the recycled asphalt mixture met the standard requirements absolutely, but also the compaction quality of the recycled pavement was improved. © (2013) Trans Tech Publications, Switzerland.
Yu H.-F.,Nanjing University of Aeronautics and Astronautics |
Sun W.,Nanjing Southeast University |
Li M.-D.,Shenyang Jianzhu University |
Li M.-D.,Tianjin Municipal Engineering Research Institute
Harbin Gongye Daxue Xuebao/Journal of Harbin Institute of Technology | Year: 2010
To study the durability of concrete subjected to multiple damage factors, by adopting high concentration chemical attack solutions, we investigated the strength development of ordinary Portland cement concrete (OPC), high-strength concrete (HSC), high-performance concrete (HPC), steel fiber reinforced high-performance concrete (SFRHPC) and high elasticity module polyethylene fiber reinforced high-performance concrete (HEMPFRHPC) subjected to double damage factors (DDF), which are the combined actions of freezing-thawing cycles and chemical attack, and multiple damage factors (MDF), which are the combined actions of flexural load, freezing-thawing cycles and chemical attack. Results show that when subjected to 1500 cycles of DDF or 1600 cycles of MDF, the compressive strengths of all tested concretes are decreased. Further research indicates that there exists a critical stress ratio for flexural load to impair compressive strength of high grade concrete subjected to MDF, which is 40%, 40%, 20%, and more than 65% for HSC, HPC, PFRHPC and SFRHPC, respectively. It can be concluded that mineral admixture benefits the compressive strength of high grade concrete subjected to bittern MDF, additional steel fiber can even guarantee the continuous increase of flexural strength.
Lin J.,Jiangxi University of Science and Technology |
Jiang P.,Tianjin Municipal Engineering Research Institute
Communications in Computer and Information Science | Year: 2011
Against the risk problem in the investment decision of construction project, we can calculate the distribution probability of project evaluation index through computer simulation technology and quantitatively analyze the risks of the project in order to provide necessary decision-making information for investors and reduce blindness in decision-making. Investment risk of construction projects is mainly reflected in the form of economic risk. The combined action of various risk factors directly leads to the changes in project cash flow and ultimately affects the evaluation index of the project. This paper takes the specific water project as an example, analyzes various risk factors, and then estimate the changes caused by it in cash flows to get the cash flow including risk factors. Whereby conducting risk assessment for evaluation index to obtain the viable probability of the project, which will be regarded as a basis for investment decision. © 2011 Springer-Verlag.
Zhou W.F.,Tianjin University |
Xie W.B.,Tianjin Municipal Engineering Research Institute
Applied Mechanics and Materials | Year: 2013
As the stability of quality of hot mixed asphalt mixture (including gradation, asphalt aggregate ratio, temperature, etc) is the premise of good pavement performance of asphalt pavement, it is regarded the key of ensuring service life and pavement performance of road to ensure the quality of hot mixed asphalt mixture. This research is oriented at developing real-time quality control & monitoring system of asphalt mixture further on the basis of the established quality control system of mixing plant. The functions and operating principles of the system are introduced in this article. © (2013) Trans Tech Publications, Switzerland.
Tao J.,Tianjin University |
Song X.,Tianjin Municipal Engineering Research Institute |
Liu J.,Tianjin University |
Wang J.,Tianjin University
Chemical Engineering Science | Year: 2013
Through a lately developed boundary element method, this paper investigates the rheology of the multiple-emulsion globule with various internal structures in a contraction tube. As fine templates to prepare microcapsules for targeted drug delivery, multiple emulsions (ME) with complex structures have been generated through microfluidics. The deformation and breakup of multiple emulsions in a microchannel are critical to the transport and release of their inclusion. However, the numerical investigation of the rheology of multiple emulsions in a contraction tube is only limited to a simple case, i.e., core-shell double emulsions (CSDE), currently. In this paper, the boundary element method is employed to investigate the deformation and displacement of 2-dimensional globules of three types of multiple emulsions, i.e., concentric ME with multiple layers, double emulsions containing multiple inner droplets and ME with asymmetric internal structures, in a contraction tube. Comparing to those of CSDE, the complication of internal structures and the collision among inner droplets will subject the globule to flows with higher pressure drops when the volume flow rates are fixed. © 2013 Elsevier Ltd.
Li M.,Tianjin Municipal Engineering Research Institute |
Sun Q.,Northeast Forestry University
2011 International Conference on Electric Technology and Civil Engineering, ICETCE 2011 - Proceedings | Year: 2011
To simplify the calculation, improve accuracy and solve the problem of the large difference between test value (lateral bending stiffness D y and integrated tensional rigidity H) and actual value when drawing a box girder parallel into orthogonal isotropic plate. The unique advantages of orthotropic plate in the bridge structure static analysis are used in this paper. The difficulty of box girder bridge structure simulation method D y is considered as a breakthrough. According to parallel hollow frame, D y can be calculated. Equivalent general formula have been derived by match of hollow frame, then it substituted into the H formula which expressed by D x & D y and been derived by heterosexual plate theory. Then compare the theoretical analysis of orthotropic plates which simplify the calculation, and improves accuracy of calculation, and been derived by the load test of Suifenhe small-radius curved bridge. The results obtained by this method and the results obtained by the finite element method in good agreement, which simplifying the calculation and improving accuracy of calculation. This method can be applied in stress analysis of other small-radius curved bridge. © 2011 IEEE.
Yang X.,Shaanxi Provincial Expressway Construction Group CO. |
Bi Y.,Chang'an University |
Zhang J.,Chang'an University |
Liu S.,Tianjin Municipal Engineering Research Institute
Geotechnical Special Publication | Year: 2016
This paper presents an experimental approach to investigate the influence of aggregate shape and angularity on the mixing property and mechanical behaviors of asphalt mixtures. A digital image technique was employed to quantify aggregate shapes and angularities. Seven different asphalt mixtures were tested by the mixing rheometer to evaluate their mixing behaviors. Creep and dynamic modulus tests of four asphalt mixtures were performed to measure creep deformation and dynamic modulus. The testing results were linked to the corresponding aggregate morphological index. It is indicated that mixing torques increase with the increasing shape index and angularity. In terms of creep deformation and dynamic modulus, natural aggregates were better than glass aggregates, and the aggregates with bigger-shape index and less-angularity will increase the creep deformation and decrease the dynamic modulus. © 2016 ASCE.
Yan Y.-H.,Tianjin Municipal Engineering Research Institute |
Sun Y.-G.,Tianjin Municipal Engineering Research Institute |
He L.-Z.,Tianjin Municipal Engineering Research Institute
Bridge Construction | Year: 2013
To ensure that the geometric shapes, cable forces and stress of the completed bridge of the New Tuanbo Bridge (a hybrid girder cable-stayed bridge with a single inclined column pylon and spatial twisted back stays) in Tianjin could meet the relevant requirements in the design and codes and in the light of the structural characteristics and the major construction process of the bridge, it was determined that the geometric shapes of the pylon of the bridge were to be mainly controlled in the construction. The cable forces of the stay cables were to be determined, using the optimization method based on the forward assembling calculation method and the principles of the least square method. The tensioned cable forces were to be controlled in two stages of the cantilever construction and system transformation of the pylon. The cable forces of the back stays and front stays were to be regarded as the critical structural parameters to be particularly identified in the parameter identification. The control of the target geometric shapes of the pylon was to be realized through the control of the assembling geometric shapes of the pylon column and the cable force adjustment. In the construction process of the pylon, the rational tensioning sequences of the stay cables were necessarily to be adopted so as to ensure the safety of the internal forces of the pylon in both the construction and completed bridge state. The control of the geometric shapes of the pylon included two parts of the assembling geometric shapes and the global posture of the pylon column. After the construction of the bridge was finally completed, the various control parameters of the bridge proved to meet the requirements in the design and codes.
Jun Z.,Tianjin Municipal Engineering Research Institute
ICPTT 2012: Better Pipeline Infrastructure for a Better Life - Proceedings of the International Conference on Pipelines and Trenchless Technology 2012 | Year: 2013
In order to standardize the inspection and evaluation methods for Drains, by studying the non-excavation pipeline repair project in Tianjin and the surrounding areas, the quality assessment parameters, choose CCTV Inspection for the best, finally concludes the defect type, establish the condition assessment model, including structural and functional defects. Investigate the technical specification for CCTV inspection and evaluation, it can provide a reliable basis for maintenance and economic analysis. At the same time, introduce absorpted and innovated many advanced repairing technology. © 2013 American Society of Civil Engineers.
Dong J.,Tianjin Municipal Engineering Research Institute
Applied Mechanics and Materials | Year: 2012
The mechanical properties and toughening mechanism of basalt fiber reinforced concrete (BFRC) with different fibers proportion ranging from 0 to 2.5 kg/m3 were tested in the experiment. The results show that the basalt fiber has little effect on the compressive strength of BFRC, but it can improve the impact toughness of BFRC significantly. Taking impact toughness as criterion, BFRC with 0.36% basalt fiber would be the best choice. The energy absorption characteristic of BFRC with different fibers dosages increases by 1.4∼3.1 times than that of plain concrete when it is ultimately destroyed. Basalt fiber provides a secondary micro-reinforced system to BFRC when added into cement matrix. BFRC specimens show multi-cracking characteristics in the failure process, and the vice crack near the main crack is clearly observed while the final destruction. © (2012) Trans Tech Publications.