共查询到20条相似文献，搜索用时 125 毫秒
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防冻外加剂是建筑业混凝土冬季施工发展的主要方向，本文从防冻外加剂发展概况分析，从而离在冬季施工中的应用，应用中应注意：“临界强度”；正确选择设计温度；合理确定外加剂的品种；如何确定外加剂的掺量及施工注意事项。 相似文献
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外加剂在混凝土结构中被广泛应用,但其在应用过程中存在的问题必须引起重视,以便更有效地发挥外加剂的作用。 相似文献
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大庆炼化公司新建职工食堂主要结构形式为超长混凝土框架结构,经合理设置混凝土膨胀加强带,采用外加剂配制补偿收缩抗裂混凝土,进行超长混凝土结构无缝施工,取得了良好效果。 相似文献
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介绍了混凝土原材料的检测和控制中几个注意事项,讨论了用净浆流动度检验水泥、粉煤灰、外加剂之间的相互适应性及不同粉煤灰对混凝土性能的影响。 相似文献
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论述了对大体积混凝土的原材料,通过优化配合比设计、提高混凝土设计等级、选用适当外加剂、增设导流管等技术措施和先进的施工工艺,并结合测温加强养护,可以解决大体积混凝土施工中的温度裂缝问题。 相似文献
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结合具体的工程实践，对粉煤灰混凝土的具体试验进行了介绍．从水泥、细集料、碎石、外加剂、粉煤灰等试验用原材料作了阐述，并对其结果作了分析，得出掺加粉煤灰可获取高标号混凝土配合比的结论。 相似文献
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介绍了阻燃刨花板的阻燃机理及常用种类,对阻燃剂的添加方式进行探讨,分析了各种添加方式的优缺点。 相似文献
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The surfaces of handsheets containing polydiallyl-dimethylammonium chloride (PDADMAC) and anionic polyacrylamide (A-PAM) were analyzed using X-ray photoelectron spectroscopy (XPS). The observed N1s chemical shifts were compared with those of the strength additives. Chemical covalences on paper surfaces due to a small amount of polymer additives were clarified and determined by an XPS curve-fitting technique. Some of the problems associated with surface analysis of paper by XPS are discussed. The effects of strength additives on the fiber surface or between fibers are illustrated. This technique appears promising as a tool to analyze paper surfaces treated with small amounts of polymer additives.Part of this paper was presented at the 64th Pulp and Paper Research Conference, Tokyo, Japan, June 19–20, 1997 相似文献
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The influence of the 30 chemical additives on the hydration characteristics of birch wood-cement-water mixture was determined by measuring the maximum hydration temperature (T
max) and the time (t
max) required to reach the temperature. The chemical additives were tested and divided into two types depending on the pattern of exothermic reaction peak within the 24-h observation period. The wood-cement-water mixtures with additions of each of the 11 type I chemical additives showed a two-peak temperature-time curve similar to that for neat cement. CaCl2, FeCl3, and SnCl2 reached the highestT
max above 50°C. When the 19 type II chemical additives were included, the mixtures offered only one peak hydration temperature-time curve. Among them, the 10 chemical additives caused an obvious temperature increase at the beginning of the hydration reaction. The most significant effect was with the addition of diethanolamine, where the mixture produced aT
max above 50°C. The strength values (modulus of rupture, internal bond strength) of word-cement board were tested with separate additions of the 10 chemical additives arranged by the highestT
max. There was a good positive correlation betweenT
max and the strength values. In addition, the composite chemical additives were preliminarily examined to determine if they accelerated the hydration reaction of blast-furnace slag cement. The results revealed that composite chemical additives evidently accelerated the hydration reaction and the setting of blast-furnace slag cement mixed with wood. Blast-furnace slag cement can thus be considered for use as an acceptable inorganic bonding material for wood-cement panel manufacture.Part of this report was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999 相似文献
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研究了淀粉乳质量浓度、pH值、温度、盐和常用食品添加剂等对橡实淀粉粘度的影响,结果表明:淀粉质量浓度增加,橡实淀粉的粘度呈幂次方上升;酸碱都能不同程度地降低橡实淀粉的粘度;温度升高,橡实淀粉的粘度逐渐降低;不同盐、添加剂的种类和质量浓度对橡实淀粉的粘度有极显著影响;测试转速的加快,各种橡实淀粉的粘度均迅速下降;橡实淀粉糊是非顿流体. 相似文献
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我国木本植物食用色素资源及其开发利用优势 总被引：2，自引：0，他引：2
食用色素系食品和医药工业上广泛使用的一类添加剂,而合成食用色素因在人体内的累积中毒、致癌等严重毒性而被限量或禁止使用,因此开发无毒和无副作用的植物天然色素已成为食用色素开发的主流。本文回顾了木本植物的抗氧化、抗癌、抗辐射、预防疾病等多种重要的医疗保健功能,以及我国近年木本植物天然色素资源的研究成果,并对木本植物天然食用色素开发利用的优势提出了看法。 相似文献
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指出了再生混凝土是将废弃混凝土经过清洗、破碎、分级，并按一定比例相互配合后得到的，是将再生骨料作为部分或者全部骨料配置的混凝土。水灰比是影响混凝土的抗压强度的主要因素。不同的水灰比对混凝土的其它方面的性能也有一定的影响。在相同的水灰比下，普通混凝土的性能与再生混凝土的性能又是否存在着差异，是试验研究的问题。试验采用不同的水灰比，将再生混凝土与普通混凝土的强度进行了比较，分析了不同水灰比对再生混凝土强度的影响。 相似文献