| 摘要 |
<p>Compositions and methods relating to cementitious compositions are provided. The use of a blend of a rosin and a tannin to entrain air into cementitious compositions is provided. A blend of a rosin and a tannin in a weight ratio of 10:1 to 1:10 are added to a wet cementitious composition at levels of less than 1 percent by weight based on the weight of the cement and air is mixed into the cement. The resulting cement will contain, e.g. 5 percent to 10 percent by volume air which improves the resistance of the set cement to freeze damage. Also provided is a method of entraining air into a cementitious composition which employs such a blend.</p> |
