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It is known that one of the methods to prevent the cracks of cement mortar for apartment housing floors are the drying shrinkage compensation with expansion admixture. In this paper, physical, mechanical and drying shrinkage properties of cement mortar for housing floor are investigated under various material and construction condition using expansion admixture. Kinds and dosage of AE water reducing agent, fly ash contents, grain shape and grading of aggregates used, contents of Na2So4, mixing temperature and delivery times are varied. According to test results, as for the effects of the kinds of AE water reducing agent on drying shrinkage, it increase in order for melamin, lignin and naphtalene type. As dosages of AE water reducing agent increase, it reduces slightly. Drying shrinkage shows decline tendency with increase of fly ash contents. Both river sand and continuous distribution of grading make drying shrinkage reduce and, also, Large dosage of Na2So4 reduce does it. In construction factors, it shows decline tendency with low temperature, and delay of casting time of specimens. However, when mixing water is over added to compensate loss of fluidity caused by delivery time, it is increased remarkably.