INTRODUCTION 



Penetration of water into reinforced portland cement concrete 

 structures through shrinkage cracks necessitates expensive installation 

 of membranes and maintenance coatings. In addition, air infiltration 

 through these cracks increases the heating/cooling energy load. In 

 exterior walls and roofs, especially in areas where wind-driven rain is 

 a problem, attempts to bridge working cracks with flexible and expandable 

 coatings have met with only qualified success. Expansive cements were 

 developed to (1) overcome the effects of shrinkage and (2) provide 

 significant compressive prestressing for strength improvement (Ref 1). 

 Detailed recommendations for use of shrinkage-compensating expansive 

 cements were published in 1977 (Ref 2). 



Commensurate with the demands for energy conservation, sandwich- 

 type expansive concrete wall and roof panels containing insulation at 

 •mid-thickness should reduce life-cycle and energy costs of new structures 

 by up to 30%, based on contractors' cost estimates. This saving results 

 from use of concrete wall panels combining insulation and reinforcement. 

 Two of the sandwich walls include "W" Panels made by CS&M Inc. , Chino, 

 Calif., and "Impac Panel" made by Covington Brothers Building Systems, 

 Riverside, Calif. The objective of this study is to determine (1) the 

 practicability of using expansive cement mortars to prevent shrinkage 

 cracking and (2) the effective aged thermal resistance of the sandwiched 

 urethane foam, originally in contact with wet mortar (plaster) on both 

 sides . 



Research directed toward development of sandwich-type walls and 

 roofs began in FY 1976 at the Civil Engineering Laboratory, Port Hueneme, 

 Calif., but demands for research funds for other studies resulted in 

 drastically reduced support for the work in FY-TQ, -77, and -78. The 

 study was terminated in FY-78. 



In the first year of research (FY-76) , the only expansive cement 

 commercially available was Type K shrinkage-compensating cement. The 

 one chosen for experimentation that year was Type K, ChemComp patented 

 by Chemically Prestressed Concrete Corporation, Hacienda Heights, Calif. 



Wall and roof panels of the type desired for the experiments were 

 obtained from CS&M Incorporated, Chino, Calif., which makes and markets 

 the panels under the trade name "W-Panel." These panels have been used 

 in construction of houses, barns, and other structures for several 

 years; their greatest use has been outside the continental United States. 

 CS&M states that W-Panels have been used extensively on the island of 

 Guam in U.S. Government housing and that houses made with these panels 

 have successfully withstood severe typhoons. Authorities at Naval 

 Station, Guam have verified use of these panels in housing but were 

 unable to pinpoint locations. Use of W-Panels within the continental 

 U.S. has been impeded by inertia in changing current building codes. 

 The International Conference of Building Officials (ICBO) Uniform Code 

 has approved the use of the panel under their research committee recom- 

 mendation, Report No. 2440 (Ref 3). 



