陶瓷食品包装材料中有毒有害物质溶出量检测研究

针对陶瓷食品包装材料中有毒有害物质溶出的突出问题,采用德国耶拿Zeenit700型顶级火焰-石墨炉联用原子吸收光谱仪,对碗、盘等8种产品进行安全性检验评价,在检测重金属铅、镉的同时,增加了锌的溶出量检测,对国标中未曾规定的杯口及外缘析出的铅和镉含量,也进行了检测。结果显示,当产品的铅溶出量高时,相应的镉溶出量也会偏高,在不合格产品中铅、镉超标总是成对出现,并且采用我国标准比采用美国和欧盟标准合格率相对较高,我国产品的质量还有较大的差距。为提高我国陶瓷产品质量,解决陶瓷产品出口的技术贸易壁垒问题提供数据基础。     

Bond-slip constitutive relationship between bars and mortar for block masonry

Ten specimens were tested in this paper in order to study the bond behavior and the process of force transfer when bars adhered to mortar. The development of the bond stress between bars and mortar was calculated. Test results show that the maximum bond-stress is not influenced by the bar bond length and increases as the increased splitting strength of mortar for block. The local bond stress-slip curve was obtained. Then,based on the regressive analysis of test data,two bond shearing stress-slip constitutive models between bars and mortar were proposed. The models can be used in the numerical simulation or finite element analysis and provide references for the improvement of the corresponding design codes.     

聚丙烯纤维增强混凝土拉压比试验

针对聚丙烯纤维对混凝土强度和拉压比影响的问题,采用标准试验方法,对不同纤维掺量和不同纤维长度的混凝土进行立方体抗压强度试验和劈裂抗拉强度试验.结果表明,聚丙烯纤维混凝土立方体抗压强度和劈裂抗拉强度的预测模型与试验结果吻合程度较高;聚丙烯纤维混凝土拉压比在纤维掺量为0~0.1%之间递增,在纤维掺量为0.1%~0.25%之间递减;6 mm聚丙烯纤维混凝土拉压比与基准混凝土拉压比相比略有下降,12 mm聚丙烯纤维混凝土拉压比比基准混凝土提高了5.5%,聚丙烯纤维可以显著改善混凝土脆性破坏形态,提高混凝土韧性.     

Alkali-aggregate reaction suppressed by chemical admixture at 80 °C

More detailed researches of chemical admixture in inhibiting Alkali-aggregate reaction (AAR) at 80 °C curing condition were done in this paper. It seemed that AAR expansion could be long-term effectively inhibited by LiOH both at the alkali contents of 2.5% and 3.0%. In addition, there was some effect on AAR suppression of the alkali reactivity of the aggregate, the alkali content of the mortar and the added amount of the admixture. Firstly, the higher the alkali reactivity of the aggregate was, the better the inhibiting effect of LiOH showed. Secondly, to the mortars with the same aggregate, the inhibiting effect of LiOH with the same n(Li)/n(Na) molar ratio was improved with the augmentation of alkali content. Thirdly, when added to some extent, further augmentation of LiOH in mortar was not effective in increasing the AAR inhibition obviously. In the last, direct results of lithium compounds in suppressing AAR were found by SEM and EDS and the mechanism was discussed.     

FRP与砌体界面的粘结承载力

目的 建立FRP与砌体界面的粘贴承载力模型.方法 对8个试件进行FRP与砌体界面的粘结强度的试验,试验前需对FRP浸胶处理,采用液压千斤顶等速连续加载,拉拔力由荷载传感器计量,纤维片材的应变采用电阻应变计测量,试验数据由UCAN70A采集.结果 结合试验数据,考虑块体、砂浆强度和考虑FRP布约束的因素,建立新的FRP与砌体界面的粘贴承载力计算公式.结论 提出的FRP与砌体界面的粘结承载力计算模型,为广大工程计算人员提供计算依据.     

我国玻璃表面装饰的现状及发展方向

将高技术与传统艺术相融合对21世纪玻璃表面装饰是颇具吸引力的;同时玻璃表面装饰应与多功能材料、复合材料、智能材料相结合。     

装配式混凝土阶梯钢板式节点应力应变分析

目的研究装配式混凝土阶梯钢板式节点的应力应变分布规律,提出一种装配式混凝土阶梯钢板式节点.方法以混凝土强度和穿心板厚度为参数制作装配式混凝土阶梯钢板式节点,以节点试件的外加梁其两端加载点的竖向荷载和位移、节点的核心区柱应力分布、节点核心区穿心钢板应力分布以及外加梁的应力分布等作为主要量测内容.对试件进行低周往复加载试验.结果穿心钢板的应变大多表现为横向应力应变远大于纵向应力应变,外加梁上梯段钢筋的应变远大于其下梯段钢筋的应变.在其他参数不变的情况下,装配式混凝土阶梯钢板式节点的混凝土强度越高则其主要受力部位的应力应变越小;穿心钢板越厚其主要受力部位的应力应变就越小;节点试件的承载力随混凝土强度提高而增大.其中极限荷载在混凝土强度C20时为110.5 k N,C40则达到228.94 k N,较C20提高107.2%.结论提出的装配式混凝土结构梁柱节点构造具有较好的应用价值,为今后预制装配式混凝土结构深入研究及推广提供试验与理论基础.     

不同表面特征GFRP筋加固钢筋混凝土T形梁抗剪试验研究

为研究不同表面特征的GFRP筋对加固后钢筋混凝土梁抗剪性能的影响,以不同混凝土强度等级、不同纵筋配筋率以及不同表面特征GFRP筋为参数,对9根钢筋混凝土T形梁进行了表面内嵌GFRP筋的静力加载试验,并分析其影响因素。结果表明,GFRP筋的表面特征是影响加固梁破坏形态的重要因素,光圆GFRP筋加固梁更容易发生粘结破坏。内嵌GFRP筋不能提高试验梁的纯弯段开裂荷载,但能提高弯剪段开裂荷载、屈服荷载和极限荷载。光圆GFRP筋加固对弯剪段开裂荷载影响显著,螺纹GFRP筋加固对屈服荷载和极限荷载影响明显。GFRP筋的表面特征对加固梁抗剪承载力的影响要大于混凝土强度等级和纵筋配筋率。GFRP筋表面特征对其应变大小有明显影响,螺纹GFRP筋的应变远大于光圆GFRP筋,因此螺纹GFRP筋利用率高,加固效果好。