高温煅烧贝壳粉的抗菌性能研究

将贝壳粉在200℃～1 100℃范围内进行煅烧改性,通过红外光谱(FT-IR)、X射线衍射(XRD)对改性贝壳粉中官能团和矿物组成进行表征分析,并通过抑菌圈试验和抗细菌率测定试验,研究不同煅烧温度对贝壳粉抑菌效果的影响.试验表明,煅烧温度为1 100℃时贝壳粉抑菌效果最佳.     

煅烧温度对高岭土性质的影响

对湖北某地红岩崖的块状沉积型高岭土矿石进行化学成分分析、物相分析以及热重分析,原矿中高岭石含量达90%以上.探索了煅烧温度对产品白度、pH值的影响,结果显示最佳的煅烧温度区间为875～950℃,煅烧后产品白度≥80%,100g/L的高岭土产品悬浊液pH≤7,产品高岭土组分为偏高岭石.根据实验结果设定950℃的煅烧温度在某有限公司生产线进行了连续7天稳定生产的工业试验,得到白度为（82±1）、pH值为（6.20±0.2）,质量稳定且符合国家工业标准的产品.     

微硅粉和聚丙烯纤维对混凝土抗裂性研究

为使混凝土具有良好的耐久性,必须先解决混凝土的抗裂性.因此,在混凝土原材料中加入聚丙烯纤维、微硅粉、矿渣来优化混凝土的抗裂性.用试验手段和正交设计来分析不同掺量时聚丙烯纤维、微硅粉以及矿渣对混凝土抗裂性能的影响.试验结果显示:聚丙烯纤维对混凝土的性能影响尤为显著;掺入微硅粉有利于增强混凝土的抗压强度和抗抗劈裂强度;复合...     

硅粉对砼技术性能的改善

介绍了硅粉掺入砼后,对其力学性能、变形性能及耐久性方面的影响,由此提出了硅粉砼施工的一些注意事项．     

微硅粉/聚丙烯复合材料制备与表征

低温煅烧微硅粉并用硅烷偶联剂Si69对其进行改性,再分别将未改性和改性微硅粉作为无机填料与聚丙烯混合后制备复合材料。未改性微硅粉掺入量为复合材料总质量的2%,改性微硅粉掺入量分别为总质量的1%、2%、3%、4%及5%,并分别在155℃、168℃、175℃温度下制备试样。测试各试样的拉伸强度、断裂伸长率、弯曲强度、冲击强度,观察其断裂面的形貌,并进行红外检测,研究改性微硅粉在不同掺量下对聚丙烯性能的影响。结果表明:改性微硅粉占复合材料质量分数的2%时复合材料的拉伸强度、弯曲强度及冲击强度得到改善;未改性或改性微硅粉加入量大于4%时会降低以上强度;用热压成型制备试样时,温度高于168℃即可成型良好。     

硅粉与纳米硅粉水泥基材料的耐酸性

为了研究硅粉与纳米硅粉作为添加剂对水泥砂浆耐酸性的影响, 本文将标准养护后的样品浸泡于pH=2的硫酸溶液中, 并分析了样品在浸泡实验前后的性能变化. 实验结果表明, 添加硅粉及纳米硅粉能有效提高浸泡前水泥砂浆的单轴抗压强度, 降低可渗透孔隙的体积率. 相较于纳米硅粉, 硅粉对水泥砂浆的性能影响更为显著. 在硫酸溶液中浸泡75 d后, 样品出现了不同程度的腐蚀. 其中, 掺5%硅粉及1%纳米硅粉的样品展现了最低的质量损失及长度损失.     

硅粉质量对甲基氯硅烷选择性的影响

根据有机硅单体合成反应机理和反应动力学,研究了原料硅粉质量、粒度及粒度分布对二甲基二氯硅烷选择性的影响,并对提高二甲基二氯硅烷选择性提出了建议.     

硅粉对混凝土抗冻性影响的研究

阐述了混凝土冻融破坏的原因、机理,并通过实验验证了硅粉对混凝土抗冻性能的影响.     

激光热解制备超细硅粉

通过激光引发化学气相热解反应。在连续流动体系中，由原料硅烷制备了超细硅粉。不同焰温制备出的粉体可以由非晶态到晶态变化，采用非接触测温技术，研究了反应参数的变化对反应焰温的影响。粉体ＴＥＭ测定结果表明为单分散球形颗粒。     

Reaction degree of silica fume and its effect on compressive strength of cement-silica fume blends

The compressive strength of the cement-silica fume blends with 5mass%, 10mass%, 20mass% and 30mass% of silica fume and water to binder ratio of 0.28, 0.32 and 0.36 from three days to ninety days were investigated. The reaction degree of silica fume was calculated from the Q4 silica tetrahedron, which was used as a probe obtained from 29 Si solid state nuclear magnetic resonance analysis. The fl at of compressive strength after 28 days disappeared for blended cement with inereasing reaction degree of silica fume. The compressive strength of the blended cement pastes approached that of P.I. cement pastes after 56 days and exceeded that after 90 days. The addition of silica fume and the w/b ratio of blends are both critical to the reaction degree of silica fume. The appropriate addition of silica fume, high silica fume reaction degree and low w/b ratio are benefi cial to the compressive strength of the cement-silica fume blends.     

单面干燥条件下掺硅灰混凝土的收缩变形分布

通过固定多组位移传感器方法,研究了单面干燥条件下不同硅灰掺量的混凝土试件距离表面不同深度处的收缩变形分布规律,同时采用埋置湿度传感器的方法研究了不同深度处的混凝土相对湿度变化规律。结果表明:混凝土试件内层的收缩和相对湿度降低明显小于表层混凝土;硅灰的掺加,能显著减小这种收缩变形与湿度梯度差。单面干燥条件下,不同深度层混凝土的收缩值与其相对湿度值之间均存在较好的线性关系;但在达到相同湿度条件时的表层混凝土收缩值小于内层混凝土。     

Properties of High Volume Fly Ash Concrete Compensated by Metakaolin or Silica Fume

The compressive strength and dynamic modulus of high volume fly ash concrete with incorporation of either metakaolin or silica fume were investigated. The water to cementitious materials ratio was kept at 0.4 for all mixtures. The use of high volume fly ash in concrete greatly reduces the strength and dynamic modulus during the first 28 days. The decreased properties during the short term of high volume fly ash concrete is effectively compensated by the incorporation of metakaolin or silica fume. The DTA results confirmed that metakaolin or silica fume increase the amount of the hydration products. An empirical relationship between dynamic modulus and compressive strength of concrete has been obtained. This relation provides a nondestructive evaluation for estimating the strength of concrete by use of the dynamic modulus.     

A Comparative Study on the Pozzolanic Activity between Nano-SiO2 and Silica Fume

The pozzolanic activity of nano-SiO2 and silica fume was comparatirely stndied by X-ray diffraction （ XRD ） , differential scanning calorimetry （DSC）, scanning electron micrascopy （SEM） and the compressive , bond and bending streugths of hardened paste and concrete were also measured. Results indicate that the compressive strength development of the paste made from Ca（OH）2 and nano-SiO2, the reaction rate of Ca（ OH）2 with nano- SiO2 and the velocity of C-S-H gel formation from Ca （ OH）2 with nano-SiO2 showed marked increases over those of Ca（ OH）2 with silica fume. Furthermore, the bond strength at the interface between aggregate and hardened cement paste, and the bending strength of concrete incorporated with 3% .NS increased more than those with SF, especially at early ages. To sum up, the pozzolanic activity of nano-SiO2 was much greater than that of silica fume. The results suggest that with a small amount of nano-SiO2, the Ca（ OH）2 crystal at the interface between hardened cement paste and aggregate at early ages may be effectively absorbed in high performance concrete.     

Analysis of the Damping Behavior and Microstructure of Cement Matrix with Silane-treated Silica Fume

The surface treatment of silca fume with silane coupling agent prior w incorporation in a cement mortar resulted in composites exhibiting increuses in loss tangent by 5%-200% and storage modulus by 10%-20% , relative to the value obtained by using as-received silica fume. The scanning electron microscopy （SEM） images iindicate that there is a morphological difference in the cement paste with treated and as-received silica fume, The, X-ray diffraction （XRD）, infrared （IR） spectrum analyses and mercury intrusion porosimetry （ MIP ） have provided evidence to understand the reaction mechanism between treated silica .fume and the hydrate product of cement. This has led to the establishment of an initial microscopic model describing the damping behavior of cement matrix.     

微波法对饮食业油烟雾吸收液的后处理

利用微波加热方法对油烟雾吸收乳浊液进行后处理 ,比较了微波加热、常规加热和自然重力沉降进行油水分离的效率 ,找出微波法处理的最佳方案 .实验结果表明 :微波法具有分离速度快、效率高的特点 ,其最佳工作条件是功率 1 50 0W ,辐射时间 8～ 1 0min.     

Influence of fly ash and silica fume on water-resistant property of magnesium oxychloride cement

By incorporation of fly ash or silica fume into magnesium oxychloride (MOC) cement, a high water resistance material can be formed for successful industrial applications. The influences of fly ash and silica fume on water-resistant property were investigated by SEM and EDS. It is found that the incorporation of fly ash or silica fume can improve the water-resistance of the MOC. The improvement of the water resistance of the MOC incorporated with fly ash or silica fume may be attributed to the alumino-silicate 5·1·8 gel or silicate 5·1·8 gel.     

高温氧化对渗硅碳化硅材料强度的影响

研究了全碳粉反应渗硅碳化硅（PCRBSC）材料,在1300℃静态空气中的高温氧化行为,研究结果表明：PCRBSC材料的气化过程遵循直线－抛物线规律,基结构对高温氧化有很大的影响,特别是游离硅fsi的含量明显影响氧化后PCRBSC材料的残余抗折强度。     

不掺硅粉的活性粉末混凝土配合比试验

在遵循活性粉末混凝土(RPC)基本配制原则的基础上,不掺入硅粉,采用超细水泥、普通水泥、掺合料(粒化高炉矿渣和粉煤灰)、砂、水、减水剂、钢纤维进行配合比试验。试验结果表明:不采用硅粉制备RPC是可行的;在制备RPC时,将超细水泥与适量掺合料混掺后,可以在保证材料强度和流动性的同时提高材料的经济性;用普通水泥取代大部分超细水泥后,材料的性能仍可保证,且更加经济。另外,研究了钢纤维掺量对材料性能(抗压、抗折、流动性及弯曲韧性)的影响规律。