CORRELATION BETWEEN TECHNOLOGICAL FACTORS AND BASIC PROPERTIES OF MECHANICALLY ACTIVATED FINE CONCRETES

Purpose. The article highlights research of the influence of fine concrete composition based on blast-furnace slag on general material properties. Time of the concrete treatment in the mixer activator is included to the influence research. Methodology. There was realized full factor experiment of 22 type with following variables: cement versus blast-furnace granulose slag ratio (X1) and time of the treatment in the mixer-activator (X2). Controlled properties are: early concrete strength (Y1=f7 day), normal concrete strength (Y2=f28 day) and average density of the concrete (Y3=ρ), hardened in normal conditions. Findings. Regress model analysis showed that decrease of the aggregate volume in concrete and increase of the mixing time grows up the strength and density of concrete. Different composition of the concrete also significantly affects concrete properties. Thus, for the same treatment time normal concrete strength at 28-day-old reduces by about 30% for compositions proportions 1:3 and 1:4, by 22% between a 1:4 and 1:5 and by 13% for 1:5 and 1:6 cases. The same behavior is obtained for early concrete strength. Density of concrete is not influenced and influence curve is almost flat. The difference between density values for different composition proportions 1:3 and 1:9 is 7.6% at equal mixture time. The increment of mixture processing time of 6 s increase normal concrete strength at 28-day-old about 7-8 % for all compositions in the studied range. Early strength values differ by 12-14 % between treatment time 30 and 36 seconds respectively. Every next six second increase step in treatment time reduce this difference by 1% for every mix compositions. There is practically no change of concrete density during the mixture time varying. Total change is 1-2% for 6 s in the entire research range for all compositions. Originality. For the first time the regression equations were determined, linking the duration of the activation of fine-grained concrete mix and its composition with the basic properties of concrete. Practical value. Regression equations and graphical surface can provide required concrete composition for the established early and normal concrete strength as well as concrete density