The influence of waste concrete addition on specific electrical conductivity of cement paste : bachelor thesis

U ovom radu provedeno je određivanje specifične električne provodnosti cementnih pasti, bez dodatka i uz dodatak 5-30 mas. % otpadnog betona. Mjerenja su provedena u termostatu pri temperaturi od 20 ℃ i pri vodocementnom, V/C = 0,5 i voda/kruto omjeru V/K = 0,5. Sve dobivene krivulje ovisnosti specifične električne provodnosti o vremenu hidratacije cementnih pasti imaju sličan grafički oblik s naglašenim vrhom maksimalne provodnosti. Vrijeme početka vezivanja za pojedini tip cementa odgovara vremenu pojave maksimalne specifične provodnosti. Iz rezultata se može zaključiti da dodatak otpadnog betona uzrokuje pad vrijednosti specifične električne provodnosti te su maksimumi pomaknuti prema kasnijim vremenima hidratacije. Također je uočena velika razlika u rezultatima specifične električne provodnosti između uzoraka portland cementa CEM I 42,5 R ULTIMO i TECNOCEM-a.In this paper, the determination of the specific electrical conductivity of the cement pastes was carried out without the addition and with addition 5-30 wt.% of waste concrete. The measurements were carried out in a thermostat at 20 °C and at the water/cement ratio, W/C=0,5 and water/solid ratio, W/S=0.5. All obtained curves of specific electrical conductivity dependence on the hydration time of the cement paste have a similar graphical shape with a pronounced peak of maximum conductivity. The start of binding time for a particular type of cement corresponds to the time of occurrence of maximum specific conductivity. From the results it can be concluded that the addition of waste concrete decreases specific electrical conductivity values. Also, a large difference in specific electrical conductivity results was observed between the Portland cement samples CEM I 42,5 R ULTIMO and TECNOCEM