The strength of modified silicate sand was examined. The results reveal that sequence of initial strength value of silicate sand is as follows: modified resin silicate sand containing -CONH2 polarity higher than modified resin silicate sand containing -COONa polarity higher than common silicate sand higher than modified resin silicate sand containing HO-O-CH2OH polarity
while the increasing sequence of final strength value is as follows: modified resin silicate sand containing -COONa polarity more than modified resin silicate sand containing HO-O-CH2OH polarity more than modified resin silicate sand containing -CONH2 polarity more than common silicate sand under the condition of the same binder addition and blowing. Comprehensive properties of modified resin silicate sand containing -COONa polarity is acceptable. In addition
with increasing in blowing time
the initial strengths of all mold sands are increased while the final strengths are decreased gradually. With increasing in blowing volume
the initial strength is declined while final strength is increased.