THE EFFECT OF AIR ENTRAINING ADMIXTURES AND CEMENT TYPES ON THE PROPERTIES OF FRESH MORTAR

A b s t r a c t In order to explain the effect of air entraining admixture (AEA) and the type of cement on the properties of fresh mortar, the following tests were carried: bulk density, flow and air content of 10 air entrained mortars and 10 non air entrained mortars made of ordinary Portland cement (OPC) and blended Portland cements: blast furnace slag (BSF) – limestone powder (LP), fly ash- limestone, fly ash (FA) and (BFS) cement. It has been found that the modern anionic AEAs from the group of alkyl sulfates are much more efficient and active than traditional ones i.e. sodium abietate. It is difficult to entrain air into mortars with cement of various types to the same content of air. This requires to carry out a number of tests to determine the appropriate amounts of AEA. The air entrainment of LP cement mortar does not significantly change its flow. The air entrainment of BSF and FA cement mortars increases their workability. The lowest content of air was stated in non-air-entrained mortars with FA cement, the highest air content was observed in BFS cement mortars. According to the results the bulk density of mortars is inversely proportional to the amount of air entrained.