CONTENTS 



page 



INTRODUCTION ........... .......... 1 



BACKGROUND 1 



INSPECTION AND RETRIEVAL. .................... 2 



RESULTS AND DISCUSSION ...................... 8 



Concrete Strength Gain ..................... 8 



Short-Term Loading of Spheres .................. 15 



Long-Term Loading of Spheres .................. 26 



Permeability ................. = 30 



Durability .. ........................ . 32 



FINDINGS 33 



SUMMARY. ............................. 3^ 



ACKNOWLEDGMENTS 3^^ 



REFERENCES ....................=. 34 



APPENDICES 



A - Effect of Drilling Cores on Compressive Strength ........ 37 



B - Early Compressive Strength Data of Spheres. 39 



C - Moisture Content of Concrete Samples '^l 



D - Cement Paste Samples Placed in the Ocean 45 



E - Microstructure Examination of Concrete 47 



