This study investigates relationships between concrete containing pozzolanic additive and mineralogical composition, porosity and chemical durability to sulphate ion containing solution. As pozzolanic admixtures micro and nano size silica and biomass ashes were used. The investigation was carried out by X-ray diffraction, Hg absorption porosimetry and optical microscopy. The pozzolanic additives activate the process of mineralization and are acting both as the cementitious admixture as well as the fine filler. The crystalline phases in all depths of the specimen, mass change, porosity were investigated after the exposure of concrete in sulphate ions containing solution for 1-6 months under static conditions. The way of sulphate attack depends on a pozzolanic additives and kind of sulphate solution. X-ray phase analysis of concrete in different depth after exposure in solution identified gypsum for concrete with additives only up to10 mm. The addition of fine dispersed additives decreases the number of pores in all range, especially in 1…10 3 μm. Cementitious properties of pozzolanic materials and crystallization of sulphate salt in pores decrease number of pores in range 0.5…10 -3 μm. Studies have shown that the pozzolanic additives reduce porosity, increase density and as a consequence increase the chemical durability of concrete to sulphate ion containing solution.

− In this work sol-gel dip-coating technique was used to synthesize ZnO and ZnO/Al films. The influence of annealing regime and dopant concentration on the structural properties of ZnO and aluminum doped ZnO (ZnO/Al) films was investigated. The surface morphology and crystallinity of ZnO films were determined using atomic force microscopy and X ray diffraction, respectively. The experimental results show that ZnO and ZnO/Al films prepared using "shock" conditions have smooth surfaces and uniform grains. Increase of aluminum concentration led to grain size reduction and denser film.

The paper describes two methods of syntheses of iron oxides, microstructure and morphology of magnetite nanoparticles. Nanocomposite thin films of SiO2/Fe3O4 have been prepared with sol-gel dip coating technique: dip-coating from SiO2/Fe3O4 sol and encapsulation magnetite between two SiO2 layers. Structural and morphological characteristics of iron oxides particles and prepared film were analyzed by X-Ray Diffraction, SEM, FTIR, DTA, AFM. AFM topography of surface and measurements of roughness has shown that using iron oxide encapsulation between two SiO2 layers to provide the even distribution of iron oxide, results as high quality films with low Rq values 1.5 2.7 nm.

Kopsavilkums. Pētītas Latvija devona (Bāles atradne) un juras perioda (Skudras atradne) kvarca smiltis kā dispersās pucolāna piedevas betonam. Veikta abu atradņu smilšu smalcināšana ūdens vidē, noteikts mineraloģiskais, granulometriskais sastāvs un morfoloģija pirms un pēc smilšu smalcināšanas. Analizēta un izvērtēta dažāda granulometriskā sastāva smilšu pucolānu reakcijas aktivitāte, nosakot to kā brīvā kalcija hidroksīda daudzumu šķīdumā. Analizēts cementa pastas hidratācijas process atkarībā no Skudras un Bāles atradņu kvarca smilšu dispersitātes un apstrādes laika. Konstatēts, ka augstas dispersitātes Latvijas kvarca smiltīm piemīt pucolāna īpašības, tās veicina cementa pastas hidratācijas procesu un kristālisko kalcija hidrosilikātu veidošanos.

Kopsavilkums. Organisko un neorganisko nanokompozītu materiālu klase ir ātri augoša pētniecības nozare. Pašlaik nemitīgi tiek meklētas jaunas iespējas uzlabot un kontrolēt to nanomēroga struktūras ar inovatīvām sintēzes metodēm. Metālu oksīdu kompozītu pielietojumu nosaka to fotokatalītiskās, magnētiskās un fotoluminiscentās īpašības.Ar nogulsnēšanas metodi iegūti Fe x O y -ZnO kompozīti ar dažādu Zn 2+ :Fe 3+ attiecību, kuru raksturošanai izmantota rentgenstaru difrakcijas analīze, Furjē-IS spektroskopija, gaismas absorbcijas un fotoluminiscences spektroskopija, kā arī veikti gāzes jutības mērījumi.Atslēgas vārdi: metālu oksīdu kompozīti, dzelzs oksīdi, cinka oksīds, nogulsnēšana, sāls šķīdumi.