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针对混凝土原材料中黏土对混凝土带来不利影响,该文通过自由基共聚反应机理,以丙烯酸(AA)、丙烯酰胺(AM)为单体,过硫酸铵为引发剂,异丙醇为链转移剂,制备了2种低分子量水溶性聚合物混凝土抑泥剂——聚丙烯酸钠(PAAS)和聚丙烯酸钠-丙烯酰胺〔P(AA-AM)〕。通过傅里叶变换红外光谱(FTIR)、热重(TGA)以及凝胶渗透色谱(GPC)对聚合物进行了表征,并通过水泥净浆流动度、混凝土坍落度和扩展度对其应用性能进行了检测。结果表明,2种聚合物抑泥剂均具有一定的抑泥性能,在高含泥量混凝土的应用中,能够显著降低水泥净浆流动度、混凝土坍落度和扩展度的损失,掺入聚合物P(AA-AM)后,混凝土1 h后的坍落度从180 mm提高到210 mm,扩展度从310 mm提高到430 mm。
Aiming at the unfavorable influence of clay in concrete raw materials on concrete, the mechanism of radical copolymerization was studied. Acrylic acid (AA), acrylamide (AM) as monomer, ammonium persulfate as initiator and isopropyl alcohol as chain transfer agent , Two kinds of low molecular weight water-soluble polymer concrete slime inhibitors - sodium polyacrylate (PAAS) and sodium polyacrylate - acrylamide [P (AA-AM)] were prepared. The polymers were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TGA) and gel permeation chromatography (GPC), and their properties were evaluated by the fluidity of cement paste, the slump and expansion of concrete Tested. The results show that the two kinds of polymeric soil-inhibiting agents all have a certain inhibition performance. In the application of high-content concrete, the fluidity of cement paste, the loss of concrete slump and expansion can be significantly reduced, After P (AA-AM), the slump of concrete increased from 180 mm to 210 mm after 1 h, and the expansion increased from 310 mm to 430 mm.