Authors:Alina Vattai and Nikoletta Rozgonyi-Boissinot
Knowledge of shearstrength along discontinuities in rock mass is essential for the design process of underground structures, such as tunnels ( Borbély et al. 2015 ), foundations, and rock slope stability
Eurocode 2 [ 9 ] considers a shearstrength which depends on the concrete cylinder strength, the flexural reinforcement ratio and the size effect factor. In case when there is no axial force in the cross-section due to loading or prestressing, the design
then decreases gradually is set. Variation curve that shearingstrength and apparent viscosity of specimens change along with the change of shearing rate is measured.
Results and discussion
The effect of
Authors:Bimlesh Lochab, Indra K. Varma, and Jayashree Bijwe
polybenzoxazine resins in nitrogen atmosphere (flow rate 60 mL min −1 ). A sample mass of 5–6 mg was used and the rate of heating was 10 K min −1 .
Lap shearstrength (LSS) of bonded joints on steel plates of roughness ( R a 0.9–1.1 μm) was measured in
Bismaleimide resin (Compimide 353) was modified with the liquid elastomer carboxyl-terminated acrylonitrile butadiene (CTBN).
The prereaction synthesis and curing of the CTBN-bismaleimide resin is discussed. The structure of the modified resin was
identified by IR and NMR spectroscopy. The basic curing mechanism is also discussed. DSC and TG were used to study the curing
behaviour and kinetic parameters, viz. the order of reaction, energy of activation and preexponential factor. Adhesive properties
such as lap shear strength and peel strength at room temperature and elevated temperature were evaluated and are discussed.
Authors:Neritan Shkodrani, Costantine Stamatopoulos, Luisa Dhimitri, and Ergys Anamali
This paper presents the stability problems of an artificial cohesion-less embankment slope supported on a saturated silty clay layer.In June 2011, an embankment about 9.00 m high started to be constructed in the Energetic Park of Porto Romano, in Durres city, Albania, as part of Preloading to Mitigate Seismic Risk project. The embankment, foreseen to be built in a conic trunk shape form, was to be used as a preload during the consolidation process of the site.Eighteen days after starting the construction process, when the embankment reached the height of 6.35 m, a soil stability failure of the embankment occurred. The calculations include the embankment slope stability analysis, during the design phase, considering the total height of the embankment (9.00 m) and at the moment of failure when the embankment height reached 6.35 m. The paper also presents the results of a back calculation of shear strength parameters at the moment of failure. Probability Based Design Method and Eurocode 7 Design Approaches are used during the analysis, considering long-term (drained) and short-term (undrained) conditions of the silty clay foundation.
Authors:Markéta Hošťálková, Nikola Vavřínová, and Veronika Longauerová
The gypsum is one of the most often used materials in the civil engineering. Very often it is applied in the form of plasterboards without any reinforcement, for example, cladding boards are unusable as supporting construction. To improve the mechanical properties of plasterboards, fibrous materials such as cellulose or glass fiber are added. Reinforcement of gypsum with fibers improves in particular the flexural and shear strength. The main purpose of the research is to clarify whether natural wooden fibers could be used as the reinforced of composite gypsum building materials. Wooden fibers are used as a blown or board thermal insulation. This article presents the results of tests aimed at determining the mechanical and physical properties of gypsum composite reinforced with wooden fibers. The effect of the reinforcement on the strength properties as a compressive strength, flexural strength was verified on a series of test specimens. The results of the tests have shown that the reinforcing of gypsum composite has an impact on the mechanical-physical parameters.