改性木质素磺酸钙高效减水剂的制备和应用

Preparation of Superplasticizer through Copolymerization of Oxidized Calcium Lignosulfonate with Acrylamide and Its Application

中文关键词:  木质素磺酸钙  氧化  共聚  丙烯酰胺  高效减水剂

Key Words:calcium lignosulfonate  oxidation  copolymerization  acrylamide  superplasticizer

中文摘要:

      用H₂O₂先对木质素磺酸钙进行氧化，然后将木质素碳酸钙氧化产物在过硫酸铵引发下与丙烯酰胺共聚，合成了一种改性木质素磺酸钙高效减水剂（AMCL）。通过红外光谱表征了氧化和共聚反应，并对AMCL进行了水泥净浆性能测试。结果表明，AMCL的分散性、缓凝性和引气性较木质素磺酸钙有明显改善，水化产物结构更加密实；在AMCL掺量为水泥质量的0.5%、水灰比为0.35时，水泥净浆流动度达245 mm；标准稠度下，AMCL掺量为0.5%时，水泥净浆减水率达到15.7%，3 d、7 d和28 d硬化水泥浆体的抗压强度比分别为119.7%、126.7%和121.0%，抗折强度比分别为109.5%、126.7%和123.4%。

Abstract:

      Calcium lignosulfonate was oxidized by H₂O₂ first. Then the oxidized product was copolymerized with acrylamide using ammonium persulfate as the initiator. A modified calcium lignosulfonate super plasticizer admixture named AMCL was synthesized. Fourier transform infrared spectroscopy was used to indicate the oxidation and grafting process, and the influence of AMCL on the performance of cement paste was investigated. The results showed that AMCL improved the character of retardation and air entrainment of calcium lignosulfonate greatly. The structure of cement hydration products was tighter. When the intermingled quantity of AMCL was 0.5% based on cement mass, water cement ratio was 0.35, the fluidity of cement paste reached 245 mm. And under condition of normal consistency and 0.5% intermingled quantity, the water-reducing rate was 15.7%. The compression strength ratios of hardened cement paste in 3 d, 7 d and 28 d were 119.7%、126.7% and 121.0%, and the flexural strength ratios were 109.5%, 126.7% and 123.4%, respectively.