Klimatförbättrad betong för fabriksbetong och prefabindustrin med krav på tidig hållfasthet.
(2024) In LUTVDG/TVBB VBMM01 20241Division of Building Materials
- Abstract
- This thesis addresses the effect of slag as a replacement material for Portland cement and its impact on strength development, with focus on early strength requirements. The aim of this study is to explore the possibility of improving concrete in terms of its environmental impact by using more eco-friendly material.
In the experimental part of this work, various mixtures with different slag amounts and additives (accelerators) are tested. Slag content is set to 0%, 50%, 60%, 70%, and 100%. Two additives are tested, and the strength development of these mixtures is systematically compared. Different types of cement are included in this work, with cement content varying between 0% and 100%. The curing temperature and casting temperature are... (More) - This thesis addresses the effect of slag as a replacement material for Portland cement and its impact on strength development, with focus on early strength requirements. The aim of this study is to explore the possibility of improving concrete in terms of its environmental impact by using more eco-friendly material.
In the experimental part of this work, various mixtures with different slag amounts and additives (accelerators) are tested. Slag content is set to 0%, 50%, 60%, 70%, and 100%. Two additives are tested, and the strength development of these mixtures is systematically compared. Different types of cement are included in this work, with cement content varying between 0% and 100%. The curing temperature and casting temperature are set to 15 °C to simulate winter conditions in Sweden. Curing takes place under relative humidity of 40%. Strength testing is carried out at two different curing ages, 16 hours, and 28 days. The two additives are based on nano-silica hydrate and calcium silica aluminate.
An increase in slag content generally results in slower strength development. The higher the slag content, the lower the strength achieved. Additives based on nano-silica hydrates had a greater impact on early strength in absence of slag, while their effect on the 28-day strength increased significantly with increasing slag content up to 70% slag content. The other additive, which is based on calcium silicate aluminate, exhibited similar behaviour with and without slag content. However, it negatively affected strength at 100% slag content. Compared to the additive based on nano-silica hydrates, it can be noted that the impact of calcium silicate aluminate is lower compared with nano-calcium silica hydrate.
An investigation of temperature development during the curing process showed that the temperature is affected by slag content and the type of additive. The results show that the maximum temperature achieved after the acceleration phase is inversely proportional to slag content. Additionally, the maximum temperature is reached earlier with lower slag content in the mixture. The addition of accelerators caused a shortening of the induction period and an increase in the maximum temperature. (Less) - Abstract (Swedish)
- Detta examensarbete behandlar effekten av slagg som ersättningsmaterial till Portlandcement och dess påverkan på hållfasthetsutvecklingen, med krav på den tidiga hållfastheten. Syftet med denna studie är att undersöka möjligheten att förbättra betong med hänsyn till dess klimatpåverkan genom att ersätta en del av Portlandcement med ett mindre miljöbelastande bindemedel.
I den experimentella delen till detta arbete undersöktes påverkan av att ersätta Portlandcement med masugnsslagg. Ett antal recept provades med olika slaggmängder samt olika tillsatsmedel i form av acceleratorer. Slagginnehållet bestämdes till 0 %, 50%, 60%, 70% och 100%. Två olika tillsatsmedel provades och hållfasthetutvecklingen för dessa recept jämfördes systematiskt.... (More) - Detta examensarbete behandlar effekten av slagg som ersättningsmaterial till Portlandcement och dess påverkan på hållfasthetsutvecklingen, med krav på den tidiga hållfastheten. Syftet med denna studie är att undersöka möjligheten att förbättra betong med hänsyn till dess klimatpåverkan genom att ersätta en del av Portlandcement med ett mindre miljöbelastande bindemedel.
I den experimentella delen till detta arbete undersöktes påverkan av att ersätta Portlandcement med masugnsslagg. Ett antal recept provades med olika slaggmängder samt olika tillsatsmedel i form av acceleratorer. Slagginnehållet bestämdes till 0 %, 50%, 60%, 70% och 100%. Två olika tillsatsmedel provades och hållfasthetutvecklingen för dessa recept jämfördes systematiskt. Olika bindemedelsammansättningar ingår i detta arbete då cementinnehållet varierar mellan 0% och 100%. Härdningstemperaturen och gjuttemperaturen var 15 °C för att simulera vinterförhållande i en betongelementfabrik i Sverige. Härdning sker under relativ fuktighet på 40%. Hållfasthensprovning utförs vid två olika härdningsåldrar, 16 timmar och 28 dygn.
Ökning i slagginnehållet resulterades generellt i långsammare hållfasthetsutveckling. Ju högre slagginnehåll, desto lägre hållfasthet erhölls. Acceleratorn som är baserat på nano-silikathydrater hade större påverkan på den tidiga hållfastheten vid frånvaro av slagg, medan dess påverkan minskade med ökande slagginnehåll. Den andra acceleratorn som är baserad på kalciumsilikataluminat hade likvärdig effekt på hållfasthetutvecklingen oavsett slaggmängden. Däremot påverkades hållfastheten negativt vid 100% slagginnehåll jämfört med motsvarande recept utan accelerator.
I denna studie undersöktes hur temperaturutvecklingen under härdningsprocessen påverkades av slagginnehåll och typ av tillsatsmedel. Resultatet visade att maxtemperaturen som uppnåddes under härdningsförloppet är omvänd proportionell mot slagginnehåll. Vidare uppnåddes maxtemperaturen tidigare ju lägre slagginnehåll ett recept innehöll. (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/9170269
- author
- Alkhalaf, Elia LU
- supervisor
- organization
- course
- VBMM01 20241
- year
- 2024
- type
- H3 - Professional qualifications (4 Years - )
- subject
- keywords
- Betong, Portlandcement, slagg, masugnsslagg, hållfasthetutvecklig, värmeutveckling, klimat, tillsatsmedel, accelerator, nano-silikathydrater, Kalciumsilikathydrat, klimatanpassad betong, klimatförbättrad betong
- publication/series
- LUTVDG/TVBB
- report number
- 5138
- other publication id
- LUTVDG/TVBB-5138-se
- language
- Swedish
- id
- 9170269
- date added to LUP
- 2024-11-26 13:16:58
- date last changed
- 2024-11-26 13:16:58
@misc{9170269,
abstract = {{This thesis addresses the effect of slag as a replacement material for Portland cement and its impact on strength development, with focus on early strength requirements. The aim of this study is to explore the possibility of improving concrete in terms of its environmental impact by using more eco-friendly material.
In the experimental part of this work, various mixtures with different slag amounts and additives (accelerators) are tested. Slag content is set to 0%, 50%, 60%, 70%, and 100%. Two additives are tested, and the strength development of these mixtures is systematically compared. Different types of cement are included in this work, with cement content varying between 0% and 100%. The curing temperature and casting temperature are set to 15 °C to simulate winter conditions in Sweden. Curing takes place under relative humidity of 40%. Strength testing is carried out at two different curing ages, 16 hours, and 28 days. The two additives are based on nano-silica hydrate and calcium silica aluminate.
An increase in slag content generally results in slower strength development. The higher the slag content, the lower the strength achieved. Additives based on nano-silica hydrates had a greater impact on early strength in absence of slag, while their effect on the 28-day strength increased significantly with increasing slag content up to 70% slag content. The other additive, which is based on calcium silicate aluminate, exhibited similar behaviour with and without slag content. However, it negatively affected strength at 100% slag content. Compared to the additive based on nano-silica hydrates, it can be noted that the impact of calcium silicate aluminate is lower compared with nano-calcium silica hydrate.
An investigation of temperature development during the curing process showed that the temperature is affected by slag content and the type of additive. The results show that the maximum temperature achieved after the acceleration phase is inversely proportional to slag content. Additionally, the maximum temperature is reached earlier with lower slag content in the mixture. The addition of accelerators caused a shortening of the induction period and an increase in the maximum temperature.}},
author = {{Alkhalaf, Elia}},
language = {{swe}},
note = {{Student Paper}},
series = {{LUTVDG/TVBB}},
title = {{Klimatförbättrad betong för fabriksbetong och prefabindustrin med krav på tidig hållfasthet.}},
year = {{2024}},
}