Advanced Materials Research Vols. 150-151

Abstract: This paper discussed the feasibility of unburned and non-autoclaved, steam cured bricks prepared by FGD byproducts from coal-fired power plants. The results show that FGD byproduct, aggregates, cementious materials and water could be used to prepare bricks during the process of stir and compaction under natural cure and steam cured condition. S4 and Z2 are the optimum design mixture composition. The maximum compressive strength and saturation coefficient are 28.7 MPa and 96.7%. FGD byproducts do no harm to environment and a pilot-scale experiment demonstrates that bricks made with FGDA can meet the MU10 level bricks technical requirement.

Abstract: In this paper, the degradation of Salix psammophila is used to make the polyurethane elastomer and study on the process involving changes in molecules with SPM. Compared with the pure polyurethane, it can be concluded that the polymerization of particles′ size, height and measurement have got bigger visibly. But the cured particles change nothing and retain the natural polymer’s linear permutation. And this polyurethane elastomer′s fracture profile is brittle.

Abstract: Attapulgite (AT)/natural rubber (NR)/ styrene-butadiene rubber (SBR) nanocomposites have been prepared after attapulgite was modified by different coupling agent. The treatment of AT caused the adhesion between AT nanorods and the nature rubber/styrene-butadiene rubber was improved, which enhanced the tensile properties of the matrix. The tensile strength of composites attained 15.6 MPa after AT was modified by 3%wt Si-69 coupling with addition of 20 phr.

Abstract: Textile reinforced concrete is a rather promising structural material which improves characteristics of traditional materials in many ways. In this paper, based on uniaxial tension experiments of TRC plates, the loading behavior of TRC plates and influence factors on their ultimate load capacity are discussed. The main parameter in the experiments is textile ratio. With the increasing of textile ratio, the efficiency of fibers decreases in a linear way, and the cracking performance is ameliorated. Moreover, a calculation formula is proposed taking the textile ratio into consideration to forecast the ultimate bearing capacity of TRC plates. Finally, according to the mixture law and ACK model, the stress-strain curve of TRC plates is simplified as a trilinear model. Providing a theoretical foundation, this investigation extends further application of TRC in practice.

Abstract: La0.7Ca0.2Sr0.1MnO3/xIrO2 (LCSMO/xIrO2) compounds were fabricated by solid state reaction method. X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Dc four probed method were used to investigate the structure, magnetic and magnetotransport properties. The results show that at low doping level (x≤0.15) IrO2 goes into the perovskite lattice substituting Mn in LCSMO, but at high doping level (x≥0.20) some part of the IrO2 substituted for Mn4+ in LCSMO lattice and the remainder resided in the grain boundaries in the form of IrO2. LCSMO/xIrO2 composites are influenced remarkabled by the IrO2 doping. With increasing IrO2 addition, the magnetic moment (s) decreases and Curie temperature (TC) decreases first, and then rises slowly of the compounds; In the doping range of 0~0.35, the resistivity rises first, and then decreases slowly, furthermore, the resistivity versus appears double peaks with increasing IrO2 addition. At room temperature, the magnetoresistance (MR) of the composites have been improved remarkably.

Abstract: By means of the three-point bending impact equipment, with the measurement of ultrasonic velocity, the impact behavior and damage evolution of reactive powder concrete (RPC) with 0, 1%, 2% and 3% volume fraction of steel fiber were tested. The results showed that steel fiber significantly improved the compressive strength, flexural strength, flexural toughness and impact toughness of RPC matrix. The compressive strength, flexural strength, flexural toughness of RPC with 3% steel fiber increased by 40.1%, 102.1%, and 37.4 times than that of plain concrete, respectively, and simultaneously, the impact toughness of RPC with 3% steel fiber was 93.2 times higher than that with 1% steel fiber. RPC with 2% and 3% steel fiber dosage both had relatively high compressive strength, flexural strength and flexural toughness; however, compared with the sample with 2% steel fiber dosage, the impact toughness of RPC with 3% steel fiber dosage increased by more than 10 times. Therefore, taking economy and applicability into consideration, if we mainly emphasis on the compressive strength, flexural strength and flexural toughness, RPC with 2% steel fiber is optimal. While if impact toughness is critical, RPC with 3% steel fiber would be the best choice.

Abstract: In this study complex cementitious systems were prepared by cement, slag, fly ash and silica fume. Changing the dosages of mineral admixtures, then studying the strength and micro-structure of harden cement pastes by XRD,SEM,BET etc. Comparing the influence of variety and dosage of mineral admixture on cement pastes.Finally we found that mineral admixtures could improve the pore size distribution of cement pastes, and the total dosage 10% is better than 20%; and the "FA+SF" is better than others.

Abstract: Salt solution ingress into concrete will result in serious deterioration of concrete materials, and then bring concrete structure in danger. So researchers pay more attention to the transportation of salt solution in concrete. In this paper, the ingress of 5% NaCl, 5%Na2SO4 and H2O into concrete under capillary siphon effect were investigated, and the influence factors such as water to binder ratio, mineral admixture, porosity and pore structure were also analyzed by methods of capillary solution-absorption experiment and evaporated water test. Results show that in capillary siphon effect, first the salt solution ingress into concrete increase quickly in very short time and then with the increase of time the solution absorption mass keep stable gradually. The types of salt solution are not the decisive factors controlling the solution ingress. Addition proper mineral admixture such as compound of fly ash (FA) and silica fume (SF) can decrease solution absorption mass under capillary siphon effect efficiently. In capillary effect, pores with aperture above 30 nm have close relativity with solution absorption mass. The decrease of porosity and improvement of pore structure can reduce the ingress of solution into concrete.

Abstract: SiC nanoparticles reinforced AZ61 magnesium composites were fabricated by Ultrasonic method. The distribution of nanoparticles in the matrix and the fracture morphology of the composites were observed by SEM, and the mechanical properties of the composites were tested at room temperature. Experimental shows that SiC nanoparticles were dispersed well in the matrix with the pretreatment method. Compared with the matrix, the tensile strength and hardness of the composites were improved respectively. Meanwhile, the ductility of the composites didn’t be obviously decreased. The enhancement function of nano composites was predicted with the dislocation strengthening and Orowan dispersion strengthening mechanisms. The predicted results coincided well with experimental ones.

Abstract: Both Ti/APC-2 cross-ply and quasi-isotropic nanocomposite laminates were successfully fabricated. Basically, the tensile tests at elevated temperature were conducted to obtain the baseline data of mechanical properties, such as strength and stiffness. The results for both types of laminates of longitudinal stiffness predicted by the rule of mixtures (ROM) were in good agreement with experimental data, whilst, those ultimate strength predicted by ROM were lower than the measured data. Then, the tension-tension (T-T) constant stress amplitude cyclic tests were performed at elevated temperature to receive the S-N curves, fatigue strength and life. It is a surprise that almost no delaminations were observed in tensile and cyclic tests, even at elevated temperature and over a million cycles.