Effect of Chemical Characteristics of Alcell Lignin-Based Methyl-Sulphonates on Their Performance as Water-Reducing Admixtures

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Title: Effect of Chemical Characteristics of Alcell Lignin-Based Methyl-Sulphonates on Their Performance as Water-Reducing Admixtures

Author(s): J. Zhor and T. W. Bremner

Publication: Special Publication

Volume: 148

Issue:

Appears on pages(s): 333-352

Keywords: admixtures; air entrainment; cements; chemical analysis; chromatography; emission spectroscopy; lignin and derivatives; mortars (material); plasticizers; rheological properties; setting (hardening); sulfur; sulphonates; tests; water-reducing agents; Mater

Date: 9/1/1994

Abstract:
High-purity lignin-based methylsulfonates were prepared by sulfomethylolation of different lignin fractions obtained in an organosolv pulp mill. These methylsulfonates were characterized and their performance in cement slurries and mortars was studied. The chemical analysis focused on determining the degree of sulfonation and molecular weight distribution. Then the 12 samples were tested as possible water-reducing admixtures for concrete. The fluidifying influence of these lignin-based methylsulfonates on cement slurries was evaluated by measuring the torque resistance in a specially developed mixing chamber. Each test involved adding the methylsulfonate in four steps of 0.2 percent by weight of cement to a portland cement slurry of water-cement ratio of 0.45. The decrease of torque resistance indicated there lative effectiveness of the various lignin samples. This test also provided a simple indication of the change in time of set caused by a particular admixture. The sulfomethylolated lignin samples were tested in cement mortars as well. The mortars were prepared with graded silica sand and normal portland cement. The plasticizing effect was determined using the flow table. The increase of flow caused by the addition of different samples in the range of 1.0 and 2.0 percent by weight of cement was tested. The air-entraining effect of these samples was determined from the unit weight measurement of fresh cement mortar. The results of this testing indicated the importance of the chemical characteristics of sulfomethylolated lignin-based water-reducing admixtures on their effectiveness in cement mortar and concrete.