Augstas izturības betona mikrostruktūras, mehānisko īpašību un ķīmiskās izturības likumsakarības

Rakstā apkopota informācija par augstas izturības betonu, tā īpašībām un izmantotām izejvielām, pamata un speciālām ķīmiskām piedevām. Apskatīti betona korozijas iemesli un notiekošie procesi. Eksperimentālajā daļā pētīti betona paraugi ar dažādu superplastifikatora daudzumu. Noteikta betona paraugu ūdens un sulfāta sāļu šķīdumu uzsūce, mineraloģiskais sastāvs, mehāniskās īpašības atkarībā no pieliktā superplastifikatora daudzuma. Pēc eksponēšanas sulfātu sāļu šķīdumos betona paraugiem veikta vizuālā novērtēšana, šķīduma pH, svara izmaiņu, mineraloģiskā sastāva izmaiņas izvērtēšana, porozitātes un spiedes stiprības noteikšana

Influence of Cenospheres on Properties of Cement Paste

The influence two composition of CS containing as crystalline phase mullite or quartz for production concrete was studied. The pozzolanic activity of CS (Q) significantly depend on dispersion and treatment time in Ca(OH)2 solution. Due to high content of amorphous SiO2, the specific character of crystalline structure of mullite and structural collapse (increase amounts of reactive Al2O3) after 14 days treatment of M specimens, a sharp increase in activity of spheres exceeded an activity of fine-grained particles. On the surface of CS (M) and broken areas, formation of amorphous white deposits and crystalline phase - calcium aluminate has been observed. CS (Q) pattern remains without significant changes on the surface of the sphere. Investigation behaviour of CS in cement paste showed pozzolanic activity of mullite containing CS and inactive character of crystalline quartz containing CS. Investigated CS dependent on chemical composition can be recommended both as reinforcing filler (crystalline quartz containing) and pozzolanic additive (mullite containing) in cement paste structure

Activity of Mullite and Quartz Containing Fly Ashes

Pozzolanic activity of two kinds of ashes with different dispersion (100-0.5 mkm) were determined during the period from 3h to 28 days. Pozzolanic activity increased up to 7.7% for crystalline quartz containing ashes (Q) and for crystalline mullite containing ashes (M) up to 9.6 by decreasing the size of particles till 0.3-12 mkm. Investigated fly ashes dependent on chemical composition can be recommended both as reinforcing filler (crystalline quartz containing) and pozzolanic additive (mullite containing) in cement paste structure