ABSTRACT:The adsorption of aniline, N-methyl aniline, and N,N-dimethyl aniline on carboxyl resin(D152) in different media, water, ethanol, and hexane have been studied. In water the adsorption affinity of three sorbates on D152 increased with an increasing number of methyl groups on N atoms, which indicated that the adsorption of the three sorbates on D152 was driven by a hydrophobic interaction. But the adsorption enthalpy of the three sorbates exceeded the van der Waals force and was in the range of hydrogen bonding interactions, which indicated that the hydrogen bonding also played an important role. In hexane the adsorption affinity decreased with the increasing number of methyl groups on the N atom, presenting the reverse order to that in water. This fact revealed that the hydrogen bonding played a predominant role for the adsorption in hexane.In ethanol, there was no adsorption of three sorbates on D152 resin, because both the van der Waals force and the hydrogen bonding interaction between the resin and sorbate were depressed. The hydrogen bonding between resin and sorbates in water was also depressed, but the hydrogen bonding adsorption remained. This result suggested that there might be a synergetic effect between the van der Waals and hydrogen bonding interactions in the adsorption of sorbate on D152 resin in water. The synergetic effect was explained thermodynamically.
Tests on rolling technology of four-graded RCC were carried out on dam site and then recommended construction parameters of four-graded RCC was proposed, which aimed to provide technique support for application of four-graded RCC in hydropower projects. Results show that when water consumption is 71kg/m3 and VC value is 3s~5s of four-graded RCC, large aggregates are coated with mortar sufficiently and the mixture has good performance of being-rolled and anti-separation. Recommended parameters of four-graded RCC are as follows: 2 times without vibration+6 times with vibration+2 times without vibration for 0.4m-thick layer, 2 times without vibration+8 times with vibration+2 times without vibration for 0.5m-thick layer, with rolling exciting force 395kN and walking speed 1.0~1.5km/h. Then the relative compaction of four-graded RCC can reach or exceed 98.0%.
Based on fractal theory and MIP data of cement stone incorporated phosphorus slag, pore volume fractal dimensions (D) were calculated, and the relationship between D and several factors were explored. Results shown: pore structure of cement stone incorporated phosphorus slag has obvious fractal characteristics, D was between 2.887 ~ 3.936. D was an important parameter to quantitatively characterize fractal characteristics, distribution of pore was more complicated when D became larger. D reduced with increased of phosphorus slag content at early, The increase of content under 50% can promote the decline of amount and diameter of pore at later. D increases with the growth of age before 90d, but at 90 d, D get lower. Spatial distribution of cement paste was more uniform when phosphorus slag became finer. Compared with singly incorporated fly ash, incorporated phosphorus slag and fly ash at the same time can further reduce D, which is the superiority of that.In recent years,with the developing of fracture mechanics and fractal theory, scholars have found that pore structure of some porous materials has obvious fractal characteristics, and D can be used to descript microporous structure and related properties such as physical and chemistry [1]~[3] . And the concept of fractal began to be applied to hole structure of hardened cement paste [4] , fractal dimension of pore area or volume was used to evaluate surface roughness and volume spatial distribution. Using related knowledge of fractal theory and MIP data, paper studied pores fractal characteristics of cement hydration products incorporated phosphorus slag, calculated pore volume D of different products, and analyzed the relationship between D and age, phosphorus slag content and specific surface area.
Using self-designed indoor detecting methods, the performance test of shotcrete doped compound admixture and crude fiber were carried out. The results showed that compound admixture and crude fiber can improve the compressive strength, flexural toughness and crack resistance of shotcrete. Axial bond strengths of shotcrete with rock were more than 1.0MPa, and that can be increased by combined-doped compound admixture and crude fiber. Rebound rates of shotcrete were 23% and 20%, layer thickness in one shot cycle were 22cm and 25cm, and combined-doped compound admixture and fiber can increase the cohesiveness and reduce rebound rate. Self-designed methods can be used to compare construction performance of different shotcretes.
The leaching characteristics of cement-fly ash pastes were investigated by MIP, XRD and TG. The results show that the microstructure of hardened cement-fly ash paste deteriorates partly after leaching of soft water. At the leaching duration of 180 days, the hardened paste containing fly ash deteriorated a little more serious than the plain cement paste, but the incorporation of fly ash in a proper ratio was helpful to defer the trend of deterioration of the hardened paste microstructure. The microstructural stability of hardened cement-fly ash paste wasn’t damaged severely during the 180 days leaching duration.
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