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The shear modulus and damping of cemented clay are investigated using ultrasound transducers, bender elements and resonant column device.Model Simsoil-CC, based on Pestana and Salvati (2006) model Simsoil, is proposed to represent the maximum shear modulus and stress-strain behavior (under cyclic loading conditions) at small strains for the cemented clay, the model can also be used for uncemented clay when cementation parameter is set to zero. Model parameters are determined for three types of clay (kaolinite, bentonite and the equal mix of kaolinite and bentonite) and two types of cementation agents (Type III Portland Cement and gypsum).The model Simsoil-CC is validated using the laboratory test data of this study and data from other studies in literature. The Simsoil-CC model can be very useful for performing earthquake site response analysis for naturally cemented clay sites or sites that have been improved by cementation. In addition, a relationship between the cementation parameter a cc CC 2 and the unconfined compression strength is proposed. The relationship simplified modeling for naturally cemented clay soil or cemented clay whose cement contents and cementation type are otherwise difficult to determine. This

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The erosion failure mechanism of concrete is studied systematically based on field investigation and laboratory experiments of concrete samples from more than 30 km concrete lining and 10 hydraulic structures of Shandong Jiaodong water diversion project, in which the concrete failed only 3-6 month after construction was completed. With electron microscopy scanning, energy dispersive analysis, XRD (X-ray diffraction) analysis and Raman spectrum analysis of the mineral composition of the failure concrete and precipitates, chemical and physical reactions that occurred in the concrete under engineering environment were investigated. The analysis indicated that the rapid corrosion and dissolution reaction of the concrete in weak sulfate environment is due to sulfate and carbonate corrosion with the catalytic magnesium salt at low temperature. Also, corrosion damage facilitates the sulfate ions and carbonate ions into the concrete, and the expansion of ettringite and TSA (thaumasite sulfate attack) reaction also accelerates the corrosion damage of the concrete.