Investigation of the variability of the structure of centrifuged and vibrocentrifuged concretes on activated Portland cement

Abstract

 In this work, a study of the variability of the structure of centrifuged and vibrocentrifuged concretes on activated Portland cement was carried out. The study of the variability of the structure of centrifuged and vibrocentrifuged concretes on activated Portland cement consisted in determining the values ​​of the densities of various layers of the sample. Also, a method was proposed for activating Portland cement in a planetary ball mill "Activator-4M". The optimal grinding mode for Portland cement has been selected. For proper fabrication of centrifuged and vibrocentrifuged samples, an experimental laboratory centrifuge TsSRL-1 with a DC electric motor and thyristor power supplies was used, and the form vibrations were carried out due to additional dowels (protrusions) put on the shafts. All samples were made from concrete of the same composition. In total, four basic samples of annular cross-section were manufactured and tested with the following dimensions: outer diameter D = 450 mm; inner hole diameter d = 150 mm; total height H = 1200 mm. The optimal values of technological parameters of centrifugation and vibrocentrifugation are given. A scheme for obtaining small-sized samples is proposed, where their production to determine the values of the densities of various layers of the sample was carried out by cutting them out of a common annular section. According to the results of the study, it was found that the activation of Portland cement at its rational values is a way to enhance variatropy.