各種混和剤を用いたコンクリートの振動締固めによる材料分離現象

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In this report, one type of air entraining agent, two types of air entraining and water reducing agents and one type of superplasticizer were used as admixtures. The concretes with these admixtures were called A, B, C and D concrete, respectively. In order to compare the segregation properties of these concretes and a plain one P, the bleeding ratio and variation of unit weight of constituent materials in the vertical direction of prismatic test pieces due to compaction by an internal vibrator were measured. The conclusions were as follows; (1) The vibrating compaction time required for the concretes with admixtures was shorter than that of plain concrete on the condition of a given slump and water cement ratio, that is, P, A, B, D1 and C concrete in the order of its magnitude, and the time for D_2 concrete with the same slump and lower water cement ratio was the shortest. (2) The degree of air loss due to vibrating compaction was C, B and A in the order of its magnitude. The larger the magnitude of air loss, the smaller the degree of segregation. (3) The bleeding ratios of A, B, C and D_1 concretes were nearly equal, and that of P concrete was larger than those up to 90 seconds of vibrating time, but decreased to the same value with prolonged vibrating time. The bleeding ratio of D_2 was equal to zero regardless of change of vibrating time. (4) The ratio of the subtraction of absolute volume of coarse aggregate in No.1 layer from that in No.4 layer concrete to that in the specified mix, (g4-g1)/g0, may be regarded as the segregation characteristic factor. The change of this factor due to vibrating compaction was closely related to the variation of mechanical properties.
1983-02-15

各種混和剤を用いたコンクリートの振動締固めによる材料分離現象

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