Applied Mechanics and Materials Vols. 268-270

Abstract: In this paper, the early hydration procedure of standard cement materials is tested and analysized with electrodeless resistivity method. The experimental results show that for standard cement material, the early hydration procedure can be divided into 4 stages: dissolution period, setting period, acceleration period and deceleration period, respectively. Moreover, the characteristic point according the experimental data can be defined to determined stage in the hydration procedure, and be related with the key parameters for cement materials in hydration procedure, such as water/cement ratio. The electrodeless resistivity method can be used to predict the hydration behavior, especially early hydration behavior of cement as a new measurement technology.

Abstract: Refractory castables containing calcium aluminate cement (CAC) are widely used in a range of furnace lining applications in the iron and steel, cement, glass, ceramic, and petrochemical industries. However, magnesia-phosphate cement (MPC) based material could be a new types of cement material, with many advantages such as rapid hydration, high early strength and circumstance suitability, which has very important value and wide application. In this study, MPC was used at Chromia/Alumina castable as binder addition instead of conventional calcium aluminate cement. Meanwhile, it also explains the relationship between the micro-mechanism and performance by micro methods such as SEM. The results shows that MPC based castables have good corrosion resistance, interface adhesiveness and abrasion resistance.

Abstract: Ship wave is one of the key factors that affect slope stability of inland waterway because of scour and corrosion. In this paper, the investigations on the softening index, the residual strain and the shear strength with cyclic loading of saturated clay were carried out through cyclic triaxial shear tests in conditions of three different ambient pressures in Naji area on the upper reaches of You River in Guangxi. The relationship between softening index and vibration times, the relationship between residual strain and vibration times as well as the shear strength discounting ratio curve varying with cyclic loading were obtained. Based on the tests, the finite element model of inland waterway slope was founded to analyze the stability of inland waterway slope under effect of ship wave.

Abstract: Analyses of REEs in 25 bulk samples collected from the Late Permian Longtan Formation in Mount Huaying district of Sichuan Province were determined useing Inductively Coupled Plasma Mass Spectrometry. The results indicate that REEs patterns are not controlled by materials from the sea, whereas the contribution of land plants is less than 0.5%. The ultimate sources of REEs are from terrigenous material as indicated by negative Eu anomaly. The Mount Emei basalt contributes to REEs enrichment of study area and all samples belong to the LREE-rich type and are enriched in LREEs relative to HREEs. So the sources of REEs are controlled by terrigenous material of Mount Emei basalt. Rare earths are an interesting group of metals that have recently become quite useful in high tech, and today they are strategic materials in the world economy. Besides, REEs play a key role in the green energy sector, REEs wide range of uses.

Abstract: Different cement types were used to stabilize coastal soft soil. The unconfined compression strength of each cement type treated soil was tested at different curing time. The results showed that the higher strength degree cement lead to the higher unconfined compression strength with same cement addition after curing 90 days. An empirical correlation between unconfined compressive strength and curing time was presented to forecast the unconfined compression strength of cement-soil. Additionally, the 14 day and the data of unconfined compressive strength at that time were suggested to use as the basic standard time and standard strength data respectively.

Abstract: In the present work we discuss on the seismic vulnerability of reinforced concrete existing buildings. In particular we consider a reinforced concrete building originally designed for only gravitational loads and located in a zone recently defined at seismic risk. According to the Italian seismic code NTC 2008 a displacement based approach is adopted and the N2-method is considered for the nonlinear seismic analysis. In the analysis all the masonry infill panels in effective interaction with the structural frame are considered for the nonlinear modeling of the structure. The influence of the effective masonry infills on the seismic response of the structure is analyzed and it is discussed how the effect of the masonry infills irregularly located within the building can give rise to a worsening of the seismic performance of the structure. It is shown that in the present case a not uniform positioning of the masonry infills within the building can give rise to a fragile structural behavior in the collapse mechanism. Furthermore a comparative analysis is performed by considering both the structure with the effective masonry infills and the bare structural frame. For these two structures a pushover analysis is performed, the relative capacity curves are derived and it is shown that fragile collapse mechanisms can occur depending on the irregular positioning of the effective masonry infills. Accordingly it is discussed how in the present case a decoupling of the effective masonry infills from the structural frame can give rise to a smoother response of the capacity curves. For the examined case of an obsolete building with irregular positioning of the masonry panels, the choice of decoupling the effective masonry panels from the structural frame may facilitate the retrofitting strategies for the achievement of the proper safety factors at the examined limit states.

Abstract: Some hot environmental issues existed at present such as building waste dump, mine subsidence and unexploited coal under buildings, railways, and water were analyzed, discussing the research status of building waste, as recycled aggregate, and technology of paste filling into mine goaf, then, the feasibility of filling the building waste into goaf was proposed. Finally, the paste filling orientation, strength, pumpability, stability, filling process design of recycled aggregate and benefit evaluation were analyzed.

Abstract: Waterproof bonding layer is an important component for permeable asphalt pavement. BISAR was used to analysis the interfacial stress under different conditions, and the rules of the tensile zone, the maximal tensile stress, the maximal interfacial shear stress and the corresponding point were obtained, which should be considered in selecting the WBL materials.

Abstract: The conventional mucking system of tunnel construction in China has a series of deficiencies and stubborn problems. Tunnel mucking technologies matched with different tunnel construction methods have been analyzed systematically and the continuous belt mucking methodology which is appropriated with drilling-blasting method was presented. The continuous belt mucking technology includes mucking scheme design and mucking equipment configuration. Compared with the conventional mucking methods, the comprehensive benefit can be fully demonstrated by the new continuous belt mucking system. On the other hand, the predominance on environmental protection of the continuous belt mucking technoloty matches up with the conservation policy. The technology would be widely applied in long tunnels and tunnels embedded in frozen ground and located in bitter cold plateau. The economic benifis and contribution to society of continuous belt mucking technology would be remarkable.

Abstract: This paper takes example of a foundation pit in Haikou, analyzing the influence on the surrounding buildings in the course of the excavation depth, daily rainfall, foundation form of the building and other factors. The results show that the excavation depth and strong rainfall may lead large deformation of the surrounding buildings, and the deep foundation pit has obvious effect on surrounding building with shallow foundation. Therefore, those factors should be considered adequately in the design and construction of deep foundation pit