【作者】 邢可；

【导师】 王立久；

【作者基本信息】 大连理工大学 ， 建筑材料， 2005， 硕士

【摘要】 丙烯酸系高效减水剂是一类聚羧酸减水剂,因具有良好的改善混凝土拌和物工作性以及硬化混凝土各种性能的作用,目前已被发达国家广泛应用。随着我国现代建筑要求的提高和混凝土技术的发展,聚羧酸系高效减水剂也必将逐步得到广泛使用。 本文以丙烯酸、丙烯酸甲酯以及它们的衍生物为主要原料,采用自由基聚合法合成了链结构和分子量分布等不同的一系列丙烯酸系高效减水剂,并进行了减水剂产品结构表征以及在水泥和混凝土中的应用性能测试。此外,本文还通过缩聚法合成了氨基磺酸系减水剂用以进行对比研究。本文主要通过红外光谱对减水剂产品进行表征,证明其结构正确;合成反应工艺通过水泥净浆流动度试验来确定,主要包括反应温度、反应物配比、引发剂种类及聚合反应时间等;通过对合成反应工艺的不断改进优选出效果较好的减水剂产品进行混凝土性能测试,主要包括新拌混凝土流动性能、坍落度经时损失和硬化混凝土力学性能的测试。 通过配方实验,确定了较为合理的工艺参数,制得一系列丙烯酸系高效减水剂,掺量为0.3%时,净浆流动度高达340mm。合成得到的丙烯酸系减水剂中包括引气型和非引气型两大类,它们的红外光谱图区别不明显;它们对水泥净浆和新拌混凝土的工作性的影响有所不同,此外掺加两类减水剂的硬化产物的力学性能和微观结构也具有很大差别。同本文合成的氨基磺酸系高效减水剂以及市售萘系减水剂进行的对比试验表明丙烯酸系减水剂和氨基磺酸系减水剂改善混凝土工作性的能力优于市售萘系减水剂;在超低掺量下与本实验室合成的改性木质素减水剂复合掺加可使拌和物具有优良的流动性。更多还原

【Abstract】 Acrylic acid superplasticizer is a kind of polycarboxylate high range water-reducer. It is widely used in developed countries due to its good properties on improving the workability of fresh concrete and performances of hardened concrete. With the development of concrete technique and modern architecture, polycarboxylate-type superplasticizer will inevitablely replace the traditional water-reducers.In this paper, using acrylic acid, methyl acrylate and their derivants as main materials, and during the free radical polymerization, synthesize a series of acrylic acid superplasticizers with different chain structure and molecular weight distribution. Besides, the polymers are characterized with FT-IR spectrum to certify the structure, and they are mixed in cement and concrete to test their properties. Moreover, a kind of sodium sulfanilate-phenol-formaldehyde condensate is synthesized through condensation polymerization process for the contrast study. The processing parameters, including reaction temperature, mixture ratio of materials, reaction initiator and reaction time etc., and technique of synthesis are mainly confirmed by fluidity of cement paste. Superplasticizers with large fluidity are filtrated to test their concrete performances, such as the fluidity of fresh concrete, the slump-loss with time and mechanical properties of hardened concrete.Some products have higher performance. For example, when the blend ratio is only 0.3%, the fluidity of cement paste can reach 340mm. The products of superplasticizers can approximately be separated into two parts: gasifying-type agent and degasifying-type agent. The FT-IR spectra of them have unconspicuous differences. However, there are large distinctions between the influences of the two types to the workability of cement paste and fresh concrete, the mechanical properties and microstructure of hardened concrete. And the contrast study shows that the sodium sulfanilate-phenol-formaldehyde condensate and the acrylic acid superplasticizers are both better than commercial product of sulphonated naphthalene formaldehyde condensates. Further more, the mixture can get a fine fluidity with acrylic acid superplasticizers, at ultra low-volume, and sodium lignosulfonate.更多还原