Structural element and method of making

Claim 1

A COMPOSITE PRESTRESSED STRUCTURE WHICH COMPRISES A PREFORMED POROUS BODY OF RELATIVELY HIGH COMPRESSIVE STRENGTH AND RELATIVELY LOW TENSILE STRENGTH, AND AN INTEGRALLY BONDED REINFORCED PLASTIC COMPOSITION LAYER, AND HAVING AS A COMPONENT OF SAID COMBINATION, A HIGH IMPACT RESISTANT SET POLYMERIC RESIN COMPOSITION PROVIDING FORCE SYSTEMS, SAID FORCE SYSTEMS PROVIDING A STATE OF INTERNAL STRESS, SAID REINFORCED PLASTIC COMPOSITION LAYER BEING BONDED IN AND TO SAID POROUS BODY AT ITS SURFACE INTERFACE BY PORTIONS OF SAID SET POLYMERIC RESIN COMPOSITION IN A STATE OF INTERNAL STRESS, AND SAID REINFORCED PLASTIC COMPOSITION BEING ADDITIONALLY BONDED BY PROJECTING PORTION OF SAID SET POLYMERIC RESIN COMPOSITION EXTENDING INTO PORTIONS OF SAID POROUS BODY AND INTEGRALLY PERMEATED, PENETRATED, ANCHORED, AND BONDED IN A STATE OF INTERNAL STRESS INTO PORES AND INTERSTICES OF SAID POROUS BODY STRUCTURE OF A DEPTH OF AT LEAST 1/32 OF AN INCH, AND REACHING AROUND AND GRIPPING THE GRAINS AND PARTICLES OF SAID POROUS BODY MATERIAL IN COMPRESSIVE STRESS, LIKE FINGERS, SUBSTANTIALLY INCREASING THE IMPACT STRENGTH OF THE POROUS BODY MATERIAL, SAID POLYMERIC RESIN COMPOSITION HAVING A HIGH STIFFNESS, TOUGHNESS, AND TENSILE STRENGTH IN ITS CURED STATE AND HAVING A LOW ORDER OF SHRINKAGE DURING SET, AND IN WHICH SAID POROUS BODY HAS AN INDUCED COMPRESSIVE PRESTRESSED PROLOAD PROVIDED BY MECHANICAL MEANS PRIOR TO COMBINATION WITH THE SAID POLYMERIC RESIN COMPOSITION, SAID POLYMERIC RESIN COMPOSITION AND SAID REINFORCED PLASTIC COMPOSITION LAYER PROVIDING TENSILE STRENGTH REINFORCEMENT AT LEAST IN EXCESS OF THE COMPRESSIVE STRENGTH OF THE POROUS BODY AND SAID INDUCED COMPRESSIVE PRESTRESSED PRELOAD PROVIDED BY MECHANICAL MEANS PRIOR TO COMBINATION WITH SAID REINFORCED PLASTIC COMPOSITION LYAER IS SUBSTANTIALLY HELD IN THE BODY OF SAID COMPOSITE STRUCTURE BY SAID SET HIGH TENSILE STRENGTH POLYMERIC RESIN COMPOSITION AFTER THE REMOVAL OF SAID MECHANICAL MEANS, WHEREBY SAID COMBINATION OF MATERIALS AND FORCE SYSTEMS PROVIDES SAID COMPOSITE PRESTRESSED STRUCTURE.