Materials Science Forum Vols. 743-744

Abstract: Liquefaction products of bamboo powder were obtained by using phenol as liquefier and 3% sulfuric acid as catalyst. Biomass phenolic resin was formed by the reaction of bamboo powder liquefaction product and formaldehyde under alkaline condition. The yield and viscosity of resin prepared under various temperatures and resinification times were studied. The result showed that biomass phenolic resin included 2-8% of tween-80, 12-28% of p-toluenesulfonic acid, 12-28% of phosphoric acid, and 10-20% of n-pentane. The viscosity measured at the foaming temperature of 70 was 2000-4000mPa·s. The density of phenolic foam plastic prepared from biomass phenolic resin was 20.78-81.51kg/m³, and the compressive strength was 18-57N/cm². Infrared spectroscopic analysis was also conducted on the biomass phenolic resin and phenolic foam.

Abstract: Accelerators have taken an important role in preparation of shotcrete. The preparation method of a new chlorine-free and alkali-free liquid accelerator was amplified, and its effects on cement setting time, mortar strength and other performances were studied. The results showed that the preparation accelerator was transparent liquid, alkali-free, chlorine-free, stabilization, and long time not to layer. When the addition ratio (in mass) of accelerator is more than 4%, such performances like setting time and mortar strength of cement reach the requirement of JC477-2005 standard. The 1d compressive strength of cement mortar was up to 14Mpa, and 28d compressive strength doe not decrease.. The best addition ratio of this accelerator is 4% to 6%.

Abstract: Three ways were used to prepare sulfide in soda-lime-silicate glass samples, i.e., glass heat-treated in N₂/H₂ (90/10 volume ratio), doped with different Carbon/Sulfur in mol ratio, as well as different sulfur source respectively. The oxidation state of sulfur on the air side surface of float glass heat-treated in N₂/H₂ and the bulk samples of the other two were determined by X-ray absorption near edge structure spectra (XANES). It was observed on the air side that: 1) A weak pre-edge exhibits at 2466.8eV which appears only with sulfite at high temperature and related to sulfur source; 2) A typical peak of sulfate at 2482.4eV decreases with increasing the temperature and heating duration. 3) Two peaks associated with sulfide, a broader one at about 2476.3eV and a sharper one with an accurate position at 2473.7eV. The S^2- content at air side of glass heat-treated at 750 is higher than that of the glass treated at other temperatures, and increases with the heating duration, which is just the reverse at 1050, because the S^2- volatilizes to the atmosphere easily at higher temperature. In addition, the content of S^2- increases with increasing C/S ratio. The local environment of S^2- in the glass with Na₂S is different from that of with FeS, as indicated by the broader resonance. The spectra indicate that the glass heat-treated in N₂/H₂ (90/10), doped with different C/S ratio and with Na₂S have the same sulfites or sulfites.

Abstract: The effects of blended steel slag-superfine fly ash mineral admixture and ordinary fly ash on the properties of concrete were compared in this study. The results show that, in the case of the same adding amount, blended steel slag-superfine fly ash mineral admixture and ordinary fly ash have similar effects on the early strength and chloride ion permeability of concrete. Blended mineral admixture has higher ability to improve the late strength of concrete than ordinary fly ash. Paste and concrete containing blended mineral admixture have smaller porosities than that containing ordinary fly ash. Blended steel slag-superfine fly ash is an ideal mineral admixture for concrete.

Abstract: Pumice is a kind of natural lightweight aggregate with well-developed porosity and moderate-intensity. Amorphous Si-Al oxide is its main mineral composition. This paper focused on the performance and features of the pumice pozzolan and aggregate firstly. Then a kind of pumice concretes was prepared with the ordinary Portland cement, ordinary sand and strengthened coarse pumice aggregates. And its mechanical properties, durability, insulation and absorbing performance were investigated. The result showed that the compressive strength of pumice concrete was 20MPa, anti-freezing durability was more than 100 freeze-thaw cycles, electric flux within 6 hours was 1749C, thermal conductivity coefficient was 0.318W/ mK, and the electromagnetic wave absorption was-5dB ranging from 8 to 18GHz. The results indicated that the pumice concrete could be developed as the green and multi-functional concrete materials in the future.

Abstract: The study on the use of blast furnace slag, steel slag and fly ash as raw materials to produce cement clinker has been carried out in the present investigation. The burnability of raw meal was determined by the linear shrinkage and free lime content of clinkers sintered at different temperatures. The microstructrue and properties of raw meal and clinker were investigated by the means of chemical analysis, X-ray diffraction and petrographic analysis. The physical and mechanical performance of cement was tested according to the standards. The results showed that the burnability was good as the free lime content was lower than 0.5w% in the clinker sintered at 1350. It is believed that the nucleation of alite only needs to grow bigger and rearrange with the rising temperature. The micrograph of clinker sintered at 1450 showed that there were some garlands of belite crystals around alite crystals because of high temperature or the local reducing atmosphere caused by the compact raw meal. High-quality cement clinker with compressive strength of 60.4MPa was produced by utilizing limestone, blast furnace slag, steel slag and fly ash as raw materials after curing 28 days.

Abstract: The effect of barium on the formation, structure and phase transition of tricalcium silicate (C₃S) has been studied by X-ray powder diffraction combined with Rietveld method, Differential scanning calorimetry and Fourier transform infrared spectroscopy. The results showed that the low contents of barium was favorable the formation of C₃S with up to 1.5% BaO. Higher amounts of BaO inhibited the C₃S crystallization and lead to preferential formation of dicalcium silicate solid solution. Three triclinic forms T1, T2 and T3 of C₃S were stabilized. The lattice parameters changed linearly to the barium content, however the discontinuity appeared at the phase transformation boundary, which follows the Vegards law. The crystallographic structure of T1 and T2 was similar to that of T3. The SiO₄^4- tetrahedra were distorted in T1 and T2, while that was approximately regular tetrahedron in T3. The phase transitions of C₃S were influenced by the incorporation of barium. It was believed that the stabilization of high temperature polymorphs of C₃S was related to the lattice distortion caused by ionic substitution.

Abstract: Based on the self-assembly of amphiphilic molecular, the dense and stable monolayer was formed at the water/air interface on the cement based materials surface. The formed monolayer could reduce water evaporation significantly at plastic stage. The results of the capillary pressure and plastic shrinkage testing at horizontal direction indicated that the inflection point of capillary pressure beginning to increase was delayed and the plastic shrinkage was decreased, which might be the reason of the decreased crack risks. And the results from hydration degree and pore structure showed that both the hydration degree and pore composition were improved, which might be beneficial to cement based materials durability. This novel monolayer technique had great potential to dissolve the plastic crack problem of cement-based materials at Northwest of China.

Abstract: The Ni-coated TiH₂ composite powder was prepared by electroless plating and the concentration of reducing agent, reaction temperature, reaction time, PH value and so on were optimized by orthogonal experiment design. The Ni/TiH₂ composite powder morphology and composition was analyzed by scanning electron microscopy (SEM), Energy Dispersive spectroscopy (EDS), X-ray diffraction (XRD); the plated Ni layer growth mechanism was explored preliminary. The Optimization technical parameters: the plating temperature was 85, the pH value was 10 and the hydrazine concentration was 100ml/L. Complete coating and uniform thickness of the Ni layer with average coating thickness about 2.0μm was successfully prepared with the optimization technical parameters. The growth mechanism of the coating followed the Ostwald ripening mechanism. Compared the TiH₂ uncoated with Ni layers particles, the TiH₂ composite powder could efficiently delay the starting time of gas release by approximately 80s.

Abstract: The efficiency of swine wastewater treatment was studied by static experiment and dynamic experiment, using sodium type mercerizing as adsorbent. The optimum parameter condition for swine wastewater treatment summarized. The experimental results showed that the optimum parameters were pH=8.0, t=24h, T=25, 300 g/L zeolite in the static experiment. In dynamic experiment when the velocity was 6 BV/h, 12 BV/h and 24 BV/h, the penetrating capacity and volume of ammonia-nitrogen, phosphorus and COD_Cr were calculated. The removal efficiency of ammonia-nitrogen, phosphorus and COD_Cr was highest under the velocity of 12 BV/h. Penetrates capacity of ammonia nitrogen and phosphorus were 4.04 mg/g and 0.14 mg/g, penetrates volume were 29 BV and 58 BV, respectively.