Consolidation of aggregate material

A method for consolidating superficial aggregate material comprising the steps of:

• (a) contacting the top surface of said aggregate with a fluid agent consisting essentially of a water-insoluble, moisture-curable NCO-terminated prepolymer and an organic solvent therefor, said prepolymer, after curing in the presence of moisture, having a tear strength of at least 75 pounds per lineal inch, an elongation of at least 100%, a tensile strength of at least 400 psi at 25% elongation, a tensile strength of at least 500 psi at 50% elongation, an ultimate tensile strength of at least 1000 psi, a dry compression strength characteristic of at least 400 psi, and a wet compression strength characteristic of at least 50 psi, and
• (b) curing said prepolymer in the presence of sufficient moisture to form a substantially nonfoamed polymer binding said aggregate together in a water-permeable mass.