AMENDING MEMORANDUM ORDER NO. 299 DATED JUNE 4, 1990 AUTHORIZING AGENCIES OF GOVERNMENT IMPLEMENTING INFRASTRUCTURE PROJECTS TO ADOPT PRE-PAYMENT BASIS IN THE PROCUREMENT OF THEIR CEMENT REQUIREMENT TO EXTEND THE EFFECTIVITY THEREOF FOR ANOTHER PERIOD OF SIX (6) MONTHS AND TO INCLUDE THEREIN REINFORCING STEEL BARS AND ASPHALT MATERIALS.