Electrode preparation and conductometric measurements in cement paste with the addition of ground brick : bachelor thesis

Za provedbu konduktometrijskih mjerenja u cementnim pastama potrebno je izraditi elektrodu otpornu na visoke pH vrijednosti te dobrih mehaničkih svojstava. Cementna pasta nakon početka vezanja otvrdnjava i prelazi u cementni kamen iz kojeg treba osloboditi neoštećenu elektrodu. Prikladan materijal je elektroda s pločicama od nehrđajućeg čelika s tvrdim polimernim tijelom ispunjenim epoksidnom smolom. Izrađenoj elektrodi potrebno je odrediti konstantu. Izvršeno je kontinuirano mjerenje specifične električne provodnosti cementnih pasti pripravljenih od CEM I uz dodatak 0 - 30 mas.% mljevene građevinske opeke. Mjerenja su provedena pri 20 °C i V/K = 0,5, a vrijednosti specifične električne provodnosti digitalno su očitavani i pohranjivani u memoriju računala svakih 5 minuta do pojave maksimalne provodnosti. Utvrđeno je da povećani dodatak mljevene opeke smanjuje vrijednosti specifične električne provodnosti te odgađa početak vezanja cementnih pasti jer se maksimalna električna provodnost događa kasnije.For execution of conductometric measurements in cement paste, it is necessary to produce an electrode resistant to high pH values and good mechanical properties. The cement paste hardens after the beginning of binding and passes into the cement stone from which the undamaged electrode is to be released. A suitable material is a stainless steel tile electrode with a rigid polymer body filled with epoxy resin. It is necessary to determine a constant for the fabricated electrode. Continuous measurement of the specific electrical conductivity of cement paste prepared by CEM was carried out with the addition of 0 - 30 wt.% of ground brick. Measurements were taken at 20 °C and V/S = 0.5, and the values of the specific electrical conductivity were digitally read and stored in the computer's memory every 5 minutes until enhanced maximum conductances. Increasing the addition of ground brick has been found to reduce the values of specific electrical conductivity and delay the beginning of cement paste bonding since the maximum electrical conductivity occurs later