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Publikācija: Investigation of Relationships: Microstructure

Publication Type Publications in RTU scientific journal
Funding for basic activity Unknown
Defending: ,
Publication language Latvian (lv)
Title in original language Augstas izturības betona mikrostruktūras, mehānisko īpašību un ķīmiskās izturības likumsakarības
Title in English Investigation of Relationships: Microstructure, Mechanical Properties and Chemical Resistance of HPC
Field of research 2. Engineering and technology
Sub-field of research 2.5 Materials engineering
Authors Janīna Sētiņa
Jūlija Petrova
Aļona Gabrene
Jānis Baroniņš
Keywords high resistance concrete, superplastificator, corrosion of concrete, absorption of salt, mineralogical composition
Abstract 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.
Abstract in English In this study, the influence of the polycarboxylates based on superplasticizer (SP) “Semflow MC” at dosages 1.0%, 1.5%, 2.5% by weight of cement on microstructure and properties of concrete was investigated. After 12 months of exposure to water, the compressive strength of concrete increased to 154.04 MPa, corresponding to the HPC. The capillary absorption of water and sulphate containing solutions of HPC depends on amount of SP; absorption of HPC 2.5 does not exceed 0.34%. The depth of penetration of solution in the samples decreases consistently by increasing amount of SP. Analysing the formation of crystalline phase during maturation, the following relationship was found: by increasing testing time from 7 to 28 days the amount of portlandite decreased and calcium hydrosilicate formed. After 12 months of exposure of HPC to sulphate containing solutions (H2SO4, Na2SO4, MgSO4), the following crystalline phases were detected: quartz, plagioclase, calcium silicates (hartrurite and tobermorite), small amount of portlandite and carbonate. The corresponding salt (from solution) compounds were not identified in the samples of concrete. It can be considered that the investigated concrete has high chemical resistance to solutions containing sulphate ions. The porosity of HPC samples varies linearly depending on the added amount of SP. After exposure to the solutions, the amount of micropore (6.10-3…10-2 m) increased for all concrete samples, but the pore distribution in a range of 500 to 1000 m did not change. The obtained results have indicated that workability of HPC increases significantly with the addition of SP. The concrete samples with low W/C ratio and SP content up to 2.5 % are characterized by high chemical resistance in sulphate containing solutions.
Reference Sētiņa, J., Petrova, J., Gabrene, A., Baroniņš, J. Investigation of Relationships: Microstructure, Mechanical Properties and Chemical Resistance of HPC. Materials Sciences and Applied Chemistry. Vol.27, 2013, pp.43-49. ISSN 14077353.
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