Rate of placement discussion for the validation of experimental models of fresh concrete lateral pressure in columns

An analysis of experimental models for predicting fresh concrete lateral pressure in columns was carried, raising the issue of a fundamental parameter like the rate of placement.Experimental data obtained from different authors were utilised for comparing the adequacy of the different theories making a division into three zones: rates of placement under 3 m/h, between 3 m/h and 10 m/h and over 10 m/h.The results were established not only in the different zones but also taking into account safety and adequacy. To determine the most suitable model according to rate of placement, level of control, vigilance, planning and inspection of the construction, eight models proposed under different standards or by different authors were compared with respect to the hydrostatic pressure produced by a liquid with concrete density.The influence of concrete yield stress, evaluated from slump test is also analyzed; the study shows a low correlation between concrete yield stress and the maximum pressure vs. hydrostatic pressure ratio.