Studies on Preparation of Concrete Water Reducer from Xylitol Residue of Corn Cob

Xylitol residue from corn cob was modified by alkaline sulfonation to produce lignosulfonate with good properties for concrete water reducing agent. Results showed that the optimum condition for lignin sulfonation was: total alkaline charge (calculated by Na2O) 16%, cooking temperature 170°C, holding time 3h, degree of sulfitation 80%. The yield of lignosulfonate at this condition was 68.1%. The fluidity of cement paste could reach 124mm when lignosulfonate dosage was 0.35% (on the base of solids). The surface tension of 1% lignosulfonate solution was 46.1 mN/m, and the content of sulfonic group was 2.16 mmol/g.