Ispitivanje trajnosti mlaznih betona

master's thesis

• Title (english): Testing durability of shotcrete
• Author: Milan Bijelić
• Mentor: Nevenka Vrbos (mentor)
• Committee member: Nevenka Vrbos (predsjednik povjerenstva)
• Committee member: Mirela Leskovac (član povjerenstva)
• Committee member: Neven Ukrainczyk (član povjerenstva)
• Granter: University of Zagreb; Faculty of Chemical Engineering and Technology; Zagreb
• Defense date and country: 2014-10-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Basic Technical Sciences; Materials

Abstract

Mlazni betoni su kompozitni materijali sa vrlo kratkim vremenom vezanja, od svega nekoliko minuta, te se u praksi koriste za sprječavanje prodora vode i stabilizaciju stijena pri izradi tunela. Od uobičajenih cementnih veziva razlikuju se po vrlo kratkom vremena vezanja i nanošenjem na površinu prskanjem u mlazu, tzv. torkretiranjem. U ovome radu istraživana je hidratacija Portland cementa (PC) i Portland cementa uz različite masene dodatke titanil sulfata (TiOSO4) odnosno komercijalnog proizvoda AS 301 kao aditiva za pripravu materijala (mlaznog betona) vrlo kratkog vremena vezanja. Utjecaj aditiva na kinetiku hidratacije praćen je in situ kalorimetrijski, te naknadnom analizom materijala rendgenskom difrakcijom. Pripravljeni materijali s dodatkom aditiva su volumno postojani (nisu skloni pojavi pukotina i pretjeranoj ekspanziji), a vrlo kratko vrijeme vezanja zadovoljava uvjet za ugradnju kompozita direktnim špricanjem. Najbolje tlačne čvrstoće postižu se s dodatkom 2% TiOSO4.

Abstract (english)

Shotcrete are composite materials with very short setting time of only a few minutes, and are used in practice to prevent water penetration and stabilization of rock in the preparation of the tunnel. A further peculiarity of this material, except for a very short time setting, is it's application to the surface by jet spraying, so-called concrete-gunning. In this work, hydration of Portland cement (PC) and Portland cement with various mass additions of titanyl sulfate (TiOSO4) or a comercial product AS 301 as an additive for the preparation of materials (shotcrete) with very short cure times has been investigated. The effect of additives on hydration kinetics was investigated in situ by calorimetry and powder X-ray diffraction of extracted material. The prepared materials have stable volumen evolution (no affinity towards cracking and expansive reactions), and very short setting times and thus satisfies the requirement for composite placement by jet spraying. Best compressive strengths are obtained with 2% of TiOSO4.

• Keywords: portland cement; ubrzivač vezanja; mlazni beton; geliranje; titanil-sulfat
• Keywords (english): portland cement; accelerators; shotcrete; gelation; titanyl sulfate
• Language: croatian
• URN:NBN: urn:nbn:hr:149:416356
• Study programme: Title: Materials Science and Engineering - Graduate study; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka kemijskog inženjerstva (magistar/magistra inženjer/inženjerka kemijskog inženjerstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2016-12-15 14:28:12