Applied Mechanics and Materials Vols. 174-177

Abstract: Sea sand concrete is a kind of concrete in which mixed sea sand as fine aggregate, which is large-scale application in the coastal areas in recent years, especially in Ningbo area. The sea sand solves the problem of river sand shortage, coupled with cheaper price, most of the ready-mixed concrete companies are willing to use desalted sea sand instead of river sand. Many companies even are using sea sand without any treatments.In Ningbo sea sand concrete using wide range of usage is not optimistic. This survey and analysis in Ningbo area physical characteristics of concrete using sea sand and sea-sand. On this basis, chloride simulating sea sand, mixed with desalted sea sand, not desalted sea sand mortar strength measurement, the concrete strength rule were analyzed, and discovered the early strength for the sea sand concrete by the presence of chloride.

Abstract: A fit-to-data technique was proposed to identify the mechanical and piezoelectric parameters of a model involving a piezoelectric laminated composite beam. Analytical solutions for displacement of the model were derived for parameter identification. The parameter identification problem was formulated as the problem of minimizing the objective function defined as a square sum of differences between the measured displacement and the computed displacement by the analytical solutions. Levenberg-Marquardt method was used to solve the minimization problem. The sensitivities of displacements with respect to the parameters were based on the finite difference approximation method. Numerical example shows that the proposed technique for parameter identification is effective.

Abstract: For expedite the development of high titanium heavy slag concrete, eight high titanium heavy slag high strength reinforced concrete (HTHS-HSRC) scale model column are studied. The eight HTHS-HSRC model columns are tested under reversed horizontal force. Primary experimental parameters include axial load ratio varying from 0.3 to 0.5, volumetric ratios of transverse reinforcement ranging from 1.38% to 1.56%, strength of high titanium heavy slag high strength concrete varying from 55.9 to 61.6 N/mm2 and configurations of transverse reinforcement. It is found from the test result that HTHS-HSRC model columns provides comparable seismic performance to those usually used reinforced concrete column in terms of member ductility, hysteretic and energy dissipation capacity. Primary Factors of Displacement Ductility of Model Columns are also discussed.

Abstract: For the quality control of commercial concrete, it is important to choose correct raw- material and mixture ratio. C40 and C50 concrete were prepared in dry and cold climate environment, using local raw materials and a large amount of fly ash. Specific researches were made about different kinds and dosage of superplasticizers on the slump of concrete, slump loss and the intensity of the impact. The results show that naphthalene series superplasticizer JK-2 and 30% of fly ash can ensure that slump of the mixture concrete reach more than 180mm, slump loss is less than 30mm in an hour, strength of hardened paste will not be reduced, and concrete can be prepared with low costs.

Abstract: As a new type of building material, bamboo flooring has been recognized in the market and becomes an ideal material in indoor decoration and refurbishing. The common quality problems of bamboo flooring mainly include the three problems of floor material quality, floor processing quality and decoration and refurbishing quality.

Abstract: The water absorbent resin is a new type of polymer plugging materials developed in recent years, the water swelling with certain viscoelastic gel, with a certain intensity, strong water retention, salt resistance and stability. Polymerization aqueous solution of acrylic acid (AA), acrylamide (AM) as the experimental materials, the choice of a controllable expansion sealing agent the KP to determine the formula developed by the sealing agent, and has good suction rate, anti-performance of salt and water retention.

Abstract: Poly(N-arylenebenzimidazole sulfone), PNABIS, has been prepared via the aromatic nucleophilic displacement reaction of 1,4-bis(2-benzimidazolyl) benzene (BBIB) with bis(4-fluorophenyl) sulfone. BBIB was synthesized by the reaction of terephthalaldehydic acid with 1,2-phenylenediamine in polyphosphoric acid. The chemical structure of BBIB was confirmed by FT-IR, high resolution mass spectrometry (HRMS) and NMR spectroscopy. The characterization of the polymer was performed with FT-IR, NMR spectroscopy, gel permeation chromatography (GPC), thermogravimetric analysis (TGA) and solubility tests. The polymer was obtained in quantitative yield with Mn value 11000 and Mw value 25300, respectively. TGA measurements show that 5% weight loss temperature is 532 °C in nitrogen and 331 °C in air, respectively. In addition, the novel polymer exhibits good solubility, which can be dissolved in common organic solvent at room temperature.

Abstract: An anti-fungal derivative of rosin, bi-quaternary ammonium salt (B-QAS) was synthesized. First, rosin was modified by acrylic acid. Then using this modified rosin reacted with an intermediate quaternary ammonium (epoxy propyl triethyl ammonium chloride) which was the reaction product of triethylamine and epichlorohydrin. The final product was bisN-(3-rosin acyloxy -2-hydroxy) propyl-N, N triethyl ammonium chloride. The chemical structure of the product and its functional groups was characterized by Fourier transform infrared spectroscopy (FTIR). Its yield of greater than 80% was conformed by high performance liquid chromatography (HPLC) and gravimetric analysis. Its anti-fungal activity was determined in vitro with a paper-disc method. B-QAS presented significant inhibitory effect for Trametes versicolor, Gloeophyllum trabeum and Postia placenta when its concentration was 0.5 mg/mL, whereas for Irpex lacteus the inhibitory effect was a little poor.

Abstract: Microcrack is the main factor that determines extension of cracks under chemical corrosion and stress in concrete. The microcrack was studied throw rapid chloride permeability method. The chloride permeability factor of six different concrete was tested to characterize total microcracks of the concrete. In order to make the conclusion of the test more reliable, microscope was used to measure the chord length of the microcracks in the concrete, and the microcraks were classified according to the length. After that, all the chord length of different classes was summed up and calculated the correlation of microcrack length and chloride permeability factor. Results showed that microcracks longer than 500µm influenced the chloride permeability factor mostly. Water reducing agent, air entraining agent, polypropylene fiber, silicon ash and fly ash added in could control the expansion of microcracks, and polypropylene fiber had the most remarkable effect.

Abstract: Superplasticizer is widespread applied in the ready-mixed concrete in China. In the specific engineering, it is not only has the requirement of water-reducing ratio for superplasticizer, but also the superplasticizer has to meet the demand such as early-strength, air-entraining, retarding and so on. In current, the naphthalene compounded superplasticizer is conducted on the basis of the FDN modification. This paper selects two kinds of representative naphthalene compounded superplasticizers, one is the setretarder superplasticizer (WRA1), and the other one is the early strength-air entraining-retarding superplasticizer (WRA2). The effect of performance on neat cement paste, mortar and concrete which mixed with the two admixtures are compared with the benchmarks (not mixed with water reducing agent) and mixed with FDN. Through the analysis and comparison of the test data, the general rules of the naphthalene compounded superplasticizer to concrete strength and shrinkage are put forward in this paper. Also, according to those rules, it poses the concrete problems to be noted in the production. This may have guidance for reducing the early cracks of ready-mixed concrete.