CONTINUOUS MEMBRANES TO SUPPLEMENT AND IMPROVE CEMENT LININGS FOR PIPE

SO LONG AS THEY REMAIN UNDAMAGED, CEMENT LININGS ARE A SATISFACTORY, LOW-COST METHOD OF PROTECTING PIPES AGAINST CORROSION. TO TEST THE EFFECT OF DAMAGING THE LINING, LABORATORY TESTS WERE CONDUCTED WITH A CLEANED STEEL SURFACE COATED WITH A MEMBRANE MATERIAL. MORTAR MIX WAS APPLIED OVER THE MEMBRANE AND CURED, THE EDGES WERE SEALED WITH EPOXY, THE CEMENT WAS CRACKED, AND THE SPECIMEN WAS IMMERSED IN AERATED 5% BRINE FOR PERIODS RANGING FROM 21 DAYS TO A YEAR. THE RESULTS SHOW THAT CORROSION TAKES PLACES IN VARYING DEGREES BENEATH CRACKED CEMENT LININGS AND CAN BE PREVENTED THROUGH USE OF A MOISTURE BARRIER BETWEEN CEMENT AND STEEL. THE MOISTURE BARRIER MEMBRANE IS HIGHLY DESIRABLE WHEN IT IS NECESSARY TO USE CORROSION- SUSCEPTIBLE, ELECTRICALLY RESISTANT WELD PIPE WITH CEMENT LININGS.