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Experimental research on mechanical performance of sulphoaluminate cement rapid repair material
Published in Domenico Lombardo, Ke Wang, Advances in Materials Science and Engineering, 2021
The setting time of cement-based rapid repair material determines the speed of road repair construction and the time of opening to traffic to a large extent. This experiment selects ingredients with various mixing amounts, estimates the specific time consumed by initial setting and final setting of cement, so as to further acquire the condition of mix ratio required by the construction. The experiment is carried out mainly according to Test Methods of Cement and Concrete for Highway Engineering. It adopts sulphoaluminate cement to research the initial setting time and final setting time of cement, meanwhile, it adds different ingredients, and research the influence of various ingredients on the setting time of cement [3]. The experimental results are shown in Table 2.
Second lining cracking mechanism and safety assessment of highway tunnel
Published in Airong Chen, Xin Ruan, Dan M. Frangopol, Life-Cycle Civil Engineering: Innovation, Theory and Practice, 2021
With the rapid development of highway construction in China, the highway tunnel plays an important role in highway engineering construction as a crucial structure. In the highway tunnel, the second lining is the outermost concrete structural layer of the tunnel structure, which is mainly used as a safety stock or partially carries the surrounding rock load. However, for areas with complex surrounding rock conditions, the second lining structure is mainly responsible for most or all of the surrounding rock load (Inokuma & Inano 1996). Due to the influence of the complex surrounding rock pressure and the construction factors, the crack of the tunnel lining is almost the common problem of the highway tunnel (Figure 1). Once cracks appear in the second lining, it will directly affect the quality and operation safety of the tunnel. The causes of the second lining crack are various and complex. The prevention and the treatment of the tunnel diseases are difficult. Therefore, it is of great practical significance to research the second lining cracking mechanism, and to ensure the construction and operation safety of the tunnel.
Structural design of haul roads
Published in Thompson Roger J., Peroni Rodrigo, Visser Alex T., Mining Haul Roads, 2019
Thompson Roger J., Peroni Rodrigo, Visser Alex T.
The pavement is that portion of the designed road structure placed above the sub-grade to support and provide the running surface for traffic. It must provide strength and protection as well as a surface with desired functional properties of acceptable ride quality with adequate skid resistance and minimal dust. In general highway engineering the pavement structure would consist of a sub-base, base and wearing course as illustrated. Since selected waste rock or overburden material is typically used for the structural layers, together with the economy of constructing a single layer rather than multiple structural layers, a mine haul road would only consist of a base rather than a sub-base and base. The upper-most wearing course will provide the desired functional properties and if designed correctly, the structure as a whole will provide an adequate response to the applied wheel loads over the design life and design traffic volume of the road.
Numerical simulation and novel methodology on resilient modulus for traffic loading on road embankment
Published in International Journal of Pavement Engineering, 2021
Cafer Kayadelen, Gökhan Altay, Yakup Önal
In highway engineering, in order to construct a road having base, subbase and subgrade layers, one of the most important issues is construction costs. It is not surprising that as the thickness of these layers increases, the cost of construction increases. To minimize these thicknesses, also construction cost, under designed traffic loads it is significant to determine the technical properties of these layers accurately such as MR. The MR value reflects the rigidity and strength properties of the subbase and subgrade materials which behave inelastically under the different environmental and traffic loading conditions (AASHTO 2003). MR is experimentally obtained from cyclic triaxial test results and described as the ratio of the deviator stress (σd) to the resilient or recoverable strain (ϵr) after a large number of load cycles as can be seen in Equation (1).