Water-soluble sulfonated phenolic resins. III. Effects of degree of sulfonation and molecular weight on concrete workability

The effects of the degree of sulfonation (DS) and molecular weight (MW) of sulfonated phenolic resins (SPF) on the flow properties of cementitious mat erials were investigated. SPF resin was prepared from phenol, formaldehyde, and sodium bisulfite through a four-step reaction. It was found that an in crease in either DS or MW would enhance the dispersion effects in the syste m. The results indicate that the fluidity of cement pastes and the workabil ity of concrete increased with higher DS until the resin was fully sulfonat ed, For resins with sufficient sulfonation, the performance of cementitious materials would increase with increasing MW. Apparently, resins with MW of about 3 x 10(4) are most effective in promoting concrete properties in ter ms of workability and compressive strength. (C) 2000 John Wiley & Sons, Inc .