Applied Mechanics and Materials Vols. 204-208

Abstract: Abstract. Cold recycling technology is applied to road rehabilitation in the recent years, and it has the advantages of mixture without heating, high RAP availability, low cost, quick speed of construction etc. Cold in-place recycling technology in this paper has been summarized including applied scope, cold recycling layer type, additives and new aggregates. We gives a detailed comparison and analysis to cold recycled mixture design method, and points out important design indexes. Combined with practical engineer of the technology in China, it analyzes application prospect and development trend on cold recycling technology.

Abstract: Abstract: Water damage on asphalt pavement will accelerate pavement destruction, and decrease the service life of highway. Water stability of recycled mixture especially should be strengthened in design and construction of cold-recycled pavement. Taking for cold recycling technology as research object , We studied water stability and freeze-thaw stability of cold recycled mixture stabilized with emulsified asphalt, cement and emulsified asphalt through tests of Marshall stability and immersion Marshall、split test 、soaking split test and freeze-thaw split etc. The results obtained show that: Water stability of Cold recycled mixture stabilized two different additives all can satisfy requirement, and cold recycled mixture adding little cement has better stability. Cold recycled mixture stabilized emulsified asphalt can be used as highway base or sub-surface of pavement. The experiment research results provide a reliable reference for cold recycled mixture design and its applicability.

Abstract: In order to ensure the safety of running train against the track buckling in a sultry weather, a speed reduction scheme has been implemented in railway operating companies. However, this scheme is based on the limited knowledge on the buckling behavior of the CWR track. The rational speed reduction scheme based on the probabilistic method for the buckling of the CWR track is proposed to apply to Korea high and normal speed railway. Permissible level of the reduced speed according to the rule of restricted speed signal, accepted degree of the buckling probability, the practically managing degree of the variation of the rail temperature, and effects of the maintenance work on the track condition are reflected in the rational speed reduction scheme.

Abstract: The paper presents the fractal dimension formula of distribution of asphalt mixture aggregate diameter by the deducing mass fractal characteristics function. Taking AC-20 and SMA-20 as examples, selected 6 groups of representative grading curves within the grading envelope proposed by the present specification, and calculated their fractal dimensions. The asphalt mixture gradation has fractal dimension D (D∈(1,3)), and the fractal of continuous gradation is single while the fractal of gap-gradation shows multi-fractal with 4.75 as the dividing point. Fractal dimension of aggregate gradation of asphalt mixture reflect the structure characteristics of aggregate distribution, that is, finer is aggregate, bigger is the fractal dimension.

Abstract: This study presents the research of soil pressure distribution form of multi-stage mountain gravity retaining wall through specific engineering tests. There has a further discussion on the soil pressure calculation formula of the multi-stage gravity retaining wall in different conditions, which aims at providing the useful reference for the formal construction design.

Abstract: Layered structure (LSFRC and LHFRC) have some characteristics: the composition of complex components, influencing factors, structure forms. Fiber mixed really adds the complexity of the test and theoretical study. In view of the dry shrinkage performance, the study is done on the research of the general concrete structure (C) enhancement effect and strengthening mechanism for the wide use in engineering foundation.

Abstract: In order to study the influence degree of the different asphalt mixture surface texture structure to the test of Non-nuclear density gauge(Pave Tracker™ Plus 2701-B). This thesis utilized non-nuclear density gauge and surface sanding method for different types of mixtures were compacted density and surface texture depth test. The results showed that: It can produce certain effect, and with it the inhomogeneity of the increases. This is mainly about mixture gradation type, among them SMA-13 affect the minimum, AC-20 take second place, ATB-25 maximum. However, using the surface sand can effective to reduce its impact. So, recommendations for ATB-25 type mixture can be used to detect the surface sand, and the SMA-13 and AC-20 are not used.

Abstract: In the process of old cement concrete pavement is transformed, asphalt overlay is the common method. However, due to the cracks of the original cement concrete slab when load and temperature and humidity changes will produce a relative displacement, it can not avoid reflective cracking. So in order to prevent the reflective cracking of asphalt overlay, crush the old cement concrete pavement is the important manner. Different construction technology is divided into three kinds: cracked steady pressure, impact compaction and rubblization technology. Among these, rubblization is an important technology that utilizes in-situ crushing technique in cement concrete pavement. This article discusses the characteristics of these three techniques, and it also evaluates effectiveness.

Abstract: Cement concrete pavement is the main type of highway pavement in our country. The asphalt overlay on old concrete pavement is one of the main measures to improve the pavement performance, to improve the bearing capacity and extended service life. But, the prevention of reflection cracks is a key problem need to overcome. This paper briefly analyzes cause of the formed mechanism of reflecting crack of bituminous paving course on old cement concrete pavement, and elaborated some major technical measures of preventing or retarding reflection cracks.

Abstract: In order to research how the strong ultraviolet impact on the performance of base asphalt, it utilizes the chambers of ultraviolet ageing environmental to simulate the field ageing conditions. The high temperature properties of base asphalt under different time of ultraviolet irradiation is researched by the SHRP equipment. The results show that the influence of high temperature performance is relatively small when the base asphalt under the strong ultraviolet rays, and it has a closer relationship with the ageing time. The value of G*/sinδ that is anti-rutting factor increase 87.2% at most.