Reološke lastnosti past za samozgoščevalne betone

diplomsko delo

Marko Tučič (Author), Lucija Hanžič (Mentor), Alan Mautinger (Co-mentor), Bernardka Jurič (Co-mentor)

Abstract

Z gradnjo vse zahtevnejših objektov se je pojavila tudi potreba po betonih, ki omogočajo izdelavo vitkih konstrukcij z veliko nosilnostjo. Novi kemični dodatki omogočajo projektiranje samozgoščevalnih betonskih mešanic, ki jih pri vgrajevanju ni potrebno vibrirati saj prehajajo med armaturo in se v opažu konsolidirajo pod vplivom lastne teže. Takšni betoni dosegajo višjo kvaliteto zaradi homogene strukture in so tudi bolj ekonomični. V okviru diplomskega dela sem raziskoval reološke lastnosti cementne paste, ki je tekoča faza svežega samozgoščevalnega betona. Cementna pasta odločilno vpliva na reološke lastnosti samozgoščevalnih betonov, zato lahko na osnovi lastnosti paste sklepamo na lastnosti betona. Na ta način bistveno zmanjšamo potrebne količine materialov potrebnih za preiskave. Izvedel sem dva tipa preizkusov in sicer merjenje časa pretoka 0.9 l paste skozi standardni lijak in čas padanja kovinske kroglice skozi stolpec paste. Uporabil sem paste z različnimi deleži kamene moke glede na maso cementa in sicer od 20 do 200 %. Paste sem pripravili z različnimi vodocementnimi faktorji v območju od 0.45 do 0.70 in z maksimalno priporočeno dozo superplastifikatorja 1 % glede na maso cementa. Ugotovil sem, da se z večanjem vodocementnega razmerja povečuje fluidnost paste, saj se čas iztoka paste skozi lijak zmanjša za 92 %. Po drugi strani pa se zaradi večanja deleža polnila povečujejo notranje sile v pasti, s tem pa se povečuje kohezivnost paste in manjša njena fluidnost. Pri primerjavi časov obeh preizkusov sem ugotovil, da se pri vodocementnih faktorjih od 0.45 do 0.70 enakomerno povečuje razmerje v času pretoka skozi lijak in času potovanja kroglice skozi pasto, ki ima obliko linearne funkcije z smernim koeficientom 0.325 in napako 0,035.

Keywords

samozgoščevalni beton;cementna pasta;reološke lastnosti;

Data

Language:	Slovenian
Year of publishing:	2009
Source:	Maribor
Typology:	2.11 - Undergraduate Thesis
Organization:	UM FGPA - Faculty of Civil Engineering, Transportation Engineering and Architecture
Publisher:	[M. Tučič]
UDC:	691.34:665.7.935.6(043.2)
COBISS:	13732886
Views:	3112
Downloads:	194
Average score:	0 (0 votes)
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Other data

Secondary language:	English
Secondary title:	Rheological properties of pastes for self-compacting concretes
Secondary abstract:	Development of more complicated buildings in modern society led to progress of high quality materials also. Evolution of chemical admixtures provided modern high performance concrete and first Self-Compacting Concrete (SCC) appeared on the market. Advantage of SCC is that it can reach better quality than normal concrete, its production and casting is easier and cheaper, because SCC consolidate by itself and vibration is not required,. This research studies rheological properties of SCC pastes. Two different tests were carried out on pastes with six water-cement ratio between 0.45 and 0.70 and filler content ranging from 20 to 200 %. Superplasticizer dosage was 1 % of the mass of cement. Fluidity of pastes measured with standard funnel, where time of flow of 0.9 l of paste was measured. Cohesiveness of pastes was determined by measuring the time needed for a metal sphere to sink through a column of paste. It was found that by increasing water-cement ratio fluidity of paste also increases,thus the times of outflow have 92 % decreased. With higher filler ratio, the inner forces of paste increase which leads to higher cohesiveness, whereas the fluidity decreases. Comparison of times measured in both tests shows linear correlation between fluidity and cohesiveness, where incline of lines were found out to be 0.325 with deviation of 0.035.
Secondary keywords:	self compacting concrete;cement paste;rheological properties;
URN:	URN:SI:UM:
Type (COBISS):	Undergraduate thesis
Thesis comment:	Univ. v Mariboru, Fak. za gradbeništvo
Pages:	XI, 19 f.
Keywords (UDC):	applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;building (construction) trade;building materials;building practice and procedure;gradbeništvo;gradbeni materiali;gradbene obrti in dela;building materials;building components;gradiva;gradbeni [konstrukcijski] deli;applied sciences;medicine;technology;uporabne znanosti;medicina;tehnika;chemical technology;chemical and related industries;kemijska tehnologija;kemijske in sorodne industrije;oils;fats;waxes;adhesives;gums;resins;olja;maščobe;voski;adhezivi;gume;smole;products of the mineral oil industry;mineral oils and similar products;produkti industrije mineralnih olj;mineralna olja in podobni produkti;
ID:	986910