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新型降粘型聚羧酸减水剂的合成及性能测试

Synthesis and Performance Testing of a New Type of Viscosity-reducing Polycarboxylate Superplasticizer

  • 摘要: 为改善高强混凝土因低水胶比所导致的高粘度问题,本文以烯丙醇聚氧乙烯醚(APEG)作为功能大单体,丙烯酸(AA)、马来酸酐(MA)与特定功能酯类单体(VE)作为功能小单体,采用过氧化氢(H2O2)-抗坏血酸(Vc)氧化还原引发体系,通过水溶液自由基聚合法,在常温条件下成功合成了一种新型降粘型聚羧酸减水剂(记为 PCE-V1)。通过单因素与正交试验确定了最优合成工艺,并对所得样品进行结构表征与性能测试。表征结果表明,PCE-V1数均分子量为6743 g/mol,产物结构符合设计。PCE-V1在混凝土中的性能测试显示,在相同掺量下,掺PCE-V1的混凝土倒筒排空时间(3.35 s)显著短于常规PCE(7.35 s),塑性粘度(2.3 Pa·s)也低于对比组,且各龄期抗压强度与市售降粘型减水剂相当。PCE-V1在保持混凝土强度的同时,具有更优异的降粘效果,这为高强混凝土工作性改善提供了有效解决方案。

     

    Abstract: In order to improve the high viscosity problem of high-strength concrete caused by low water cement ratio, this paper uses allyl alcohol polyoxyethylene ether (APEG) as the functional monomer, acrylic acid (AA), maleic anhydride (MA), and specific functional ester monomers (VE) as functional monomers. Using the hydrogen peroxide (H2O2) - ascorbic acid (Vc) redox initiation system, a new type of viscosity reducing polycarboxylate superplasticizer (PCE-V1) was successfully synthesized at room temperature through aqueous free radical polymerization. The optimal synthesis process was determined through single factor and orthogonal experiments, and the obtained samples were characterized for structure and tested for performance. The characterization results indicate that the number average molecular weight of PCE-V1 is 6743 g/mol, and the product structure conforms to the design. The performance test of PCE-V1 in concrete shows that at the same dosage, the emptying time (3.35 s) of concrete poured with PCE-V1 is significantly shorter than that of conventional PCE (7.35 s), the plastic viscosity (2.3 Pa · s) is also lower than that of the control group, and the compressive strength at all ages is comparable to that of commercially available viscosity reducing water reducers. PCE-V1 not only maintains the strength of concrete, but also has a better viscosity reduction effect, which provides an effective solution for improving the workability of high-strength concrete.

     

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