Q.: Is there any general guide or rule of thumb about how much more strength you get from Type III than Type I cement at various ages?

A.: At ordinary temperatures of about 70 degrees F you can expect about 190 percent of the Type I strength at 1 day, 150 percent at 3 days, 120 percent at 7 days, and 110 percent at 28 days. At 3 months the strength of Type I and Type III would be about the same. At 40 degrees F the advantage of Type III over Type I is more pronounced and the advantage lasts for a longer time.