CARBONATION OF PORTLAND BLAST-FURNACE SLAG CEMENT CONCRETE BY 40-YEAR NATURAL AGING AND PREVENTIVE EFFECT OF FINISHING MATERIALS

摘要

This research was conducted for the purpose of elucidating the rate of carbonation of concrete specimens that were prepared separately using types A, B and C of Portland blast-furnace slag cement, and Normal Portland cement, and which have the same degree of compressive strength, on the 28th day of age and also for studying carbonation-preventive effects of different finishing materials, such as paint, mortar and tiles. The concrete specimens which were prepared by mixing concrete materials on march 27 and April 6, 1961, and subsequently compacting with considerable care, were subjected to through initial curing, and then were exposed to the indoor and outdoor atmosphere under quite common weathering conditions for 40 long-time aging does not differ with types of cement if the concrete is prepared to have the same degree of compressive strength on the 28th day of age, and is subjected to careful compaction and initial curing at the time of placing. In addition, the factor in the carbonation-rate equation that has already proposed by the author was corrected by taking the carbonated thickness measured this time into consideration. It was also quantitatively proved that finishing materials such as paint, mortar, tiles have substantial carbonation-preventive effects on the structure concrete.