. . . "Early stage of hydration of cement paste has been studied both theoretically and also experimentally. Within the framework of nonstationary nucleation theory, a model allowing to determine temporal dependence\u00A0 of electrical resistance of hardening cement"@en . "Physical properties of the hardened cement paste exhibiting a great impact in the practise are basically influenced by the nature of this porous structure. Origin of the pores is closely connected with the early stage of hydration process during whichthe calcium silicate hydrate (CSH) clusters are formed via nucleation and subsequent growth (solidification). The present team combines physicists and civil engineers to study early stage of the cement paste hydration experimentally and theoretically. Inthis project we focus on the influence of the water to cement ratio both on the induction time of CSH nucleation and on the evolution of porosity in cement gels. Electrical properties of cement solutions of various concentrations will be measured and thestrength of hardened cement paste will be determined. Changes in electrical conductivity of cement solutions of different concentrations will be correlated with the induction period of calcium silicate hydrates nucleation. This quantity characterising"@en . . "GA106/03/0028" . "1"^^ . . . "1"^^ . . "Study of early ageing of hardened cement paste"@en . "Studium ran\u00E9ho st\u00E1dia hydratace ztvrdl\u00E9 cementov\u00E9 pasty" . . . . . . . "Fyzik\u00E1ln\u00ED vlastnosti zatvrdl\u00E9 cementov\u00E9 pasty jsou siln\u011B ovlivn\u011Bny jej\u00ED por\u00F3zn\u00ED strukturou. P\u016Fvod samotn\u00FDch p\u00F3r\u016F je p\u0159itom sv\u00E1z\u00E1n s ran\u00FDm v\u00FDvojov\u00FDm st\u00E1diem hydrata\u010Dn\u00EDho procesu, kdy nukleuj\u00ED a pak rostou z\u00E1rodky hydr\u00E1tu kalciumsilik\u00E1tu. V \u0159e\u0161itelsk\u00E9mt\u00FDmu jsou zastoupeni fyzici, chemici a stavebn\u00ED in\u017Een\u00FD\u0159i (v\u010Detn\u011B doktorand\u016F) aby se zab\u00FDvali pr\u00E1v\u011B t\u00EDmto ran\u00FDm stupn\u011Bm (f\u00E1z\u00ED) hydratace experiment\u00E1ln\u011B i teoreticky. Zam\u011B\u0159\u00EDme se hlavn\u011B na vliv tzv. vodn\u00EDho sou\u010Dinitele na \u010Dasovou prodlevu nukleace a nav\u00FDvoj por\u00F3zn\u00ED struktury cementov\u00E9 pasty. Budou m\u011B\u0159eny elektrick\u00E9 vlastnosti cementov\u00FDch roztok\u016F a nap\u011Bt\u00ED zatuhl\u00E9 cementov\u00E9 pasty. Zm\u011Bny elektrick\u00E9 vodivosti cementov\u00FDch roztok\u016F r\u016Fzn\u00FDch koncentrac\u00ED budeme korelovat s \u010Dasovou prodlevou nukleace z\u00E1rodk\u016Fhydr\u00E1tu kalciumsilik\u00E1tu. Tato veli\u010Dina charakterizuje tzv. latentn\u00ED periodu hydrata\u010Dn\u00EDho procesu (v pr\u016Fb\u011Bhu kter\u00E9 je pasta stale plastick\u00E1), kter\u00E1 hraje d\u016Fle\u017Eitou \u00FAlohu ve stavebn\u00ED praxi - materi\u00E1l, je mo\u017Eno bez podstatn\u00E9 zm\u011Bny jeho vlastnosti dopravit" . "http://www.isvav.cz/projectDetail.do?rowId=GA106/03/0028"^^ . . . "0"^^ . . . "Neuvedeno."@en . . "2009-01-15+01:00"^^ . "15"^^ . . "15"^^ . . "Ran\u00E9 st\u00E1dium hydratace cementov\u00E9 pasty bylo studov\u00E1no teoreticky i experiment\u00E1ln\u011B.\u00A0 V r\u00E1mci\u00A0 nestacion\u00E1rn\u00ED nuklea\u010Dn\u00ED teorie byl vytvo\u0159en model umo\u017E\u0148uj\u00EDc\u00ED ur\u010Dit z\u00E1vislost elektrick\u00E9ho odporu\u00A0 tuhnouc\u00ED cementov\u00E9 pasty na \u010Dase. Bylo vyvinuto\u00A0 za\u0159\u00EDzen\u00ED umo\u017E\u0148"@cs . .