XYPEX NOTE: The briefing described on the cover page is a written transcript of an oral briefing and slide presentation given by a Bechtel Corporation engineer on the benefits achieved with Xypex for the Washington D.C. Metro System. Excerpts from the transcript are presented below. Complete copies are available on request.

Page 1 -- "Waterproofing of concrete and shotcrete by crystallization process was used in lieu of other waterproofing methods which were not fully effective in particular applications. These were chemical grouting, epoxy grouting, liquid applied water repellents, cementitious waterproofing, metallic waterproofing, metal panning, etc. Several waterproofing methods were employed to resolve the problems. For example, on the shady Grove Route, the grout technique was used while the tunnel was under construction. It would have probably worked over the long run, but the cost was prohibitive for results achieved. The effort was abandoned. It was replaced by XYPEX, which waterproofs concrete by crystallization. This technique has produced the desired results ... "

Page 2 -- "The purpose of this presentation is to acquaint the Washington Metropolitan Area Transit Authority (WMATA) board of Engineering Consultants with a concrete waterproofing product and system that is being successfully used in solving some of WMATA's concrete waterproofing problems in both tunnel and station areas during construction. . . .  Due to rehealing capability, the entire mass of the treated concrete becomes also permanently sealed against the penetration of water. If a minor crack re-opens in the concrete previously treated, regardless how long ago, it will close again as soon as water reaches the 'dormant' chemical in the crack."

Page 3 -- "Concrete waterproofing by crystallization has been used in shotcrete surfaces at Bethesda Station, on several tunnel sections of the Red Line, and in various applications in Tenleytown, Friendship, Woodley Park-Zoo, Cleveland and Van Ness stations."

Page 5 -- "Slide #6 shows the surface after treatment, the marked difference is obvious. The running leaks have disappeared."

Page 6 -- "Slide #7 is a closeup of the same surface after treatment. It can be clearly seen the process is effective. The crystallization process becomes fully effective in a matter of days. New leaks through a re-opened crack will reactivate crystalline growth, and again stop the leak. . . . Slide #10 is the same area after the crystalline product has been applied. The surface is entirely 'dry,' more than is required by the specification."

Page 8 -- "Slide #19 shows the same area as the previous slide, but one day after the remedial work was finished using Xypex Dry-Pac and slurry (incidentally it was taken on the opening day of the three station - Phase V Route). The happy man pointing to the vertical joint between two precast panels is the superintendent of our ancillary contractor, who subcontracted the work to XYPEX."

CERTIFIED CORRECT EXCERPTS
XYPEX CHEMICAL CORPORATION

January 29, 1985