This?
You can change the plot range using col.lim variable, with the min and max as a vector i.e. =c(min, max).
col.lim
=c(min, max)
corrplot(col.lim=c(0,1),correlation_matrix, method="circle", col = rep(rev(brewer.pal(n=8, name="RdYlBu")), 2))