Endre søk
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Impacts of Using Crushed Rocks in Concrete.
KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik, Teknisk geologi och geofysik.
2011 (engelsk)Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
Abstract [en]

Concrete in Sweden has traditionally been manufactured with natural aggregate from glaciofluvial eskers. There is a need to preserve the remaining eskers because of their cultural value and importance for water filtration, thus natural aggregate has to be replaced. The most realistic alternative is to use crushed rocks. The major problem with crushed rocks in concrete production is the workability. This is because crushed rocks have less favorable properties. The fragments are flakier and have a rougher surface than natural aggregates that have been rounded in water. Without any amelioration of the crushed rock, to reach a certain workability and strength, the amount of cement in the mix has to be increased. Cement production requires large amounts of energy and the decarbonation of limestone releases large amounts of CO2. Combined, the release of CO2, due to burning and decarbonation of limestone, accounts for about 5% of the global CO2 emissions. An increase in cement consumptions is less desirable. Thus to replace natural aggregates, the use of crushed rocks has to be optimized as regard cement consumption.

Several crushed aggregates, most from granitic rocks, from all over Sweden were analysed in this study. These crushed rocks were characterized according to their grading, specific surface, shape and petrography and compared to natural sand.

Rheological tests that reveals the workability in detail was performed on mortars. The tests showed that as regard workability the 0-2 mm fraction is the most important factor. Further, the maximum aggregate size was gradually increased up to 16 mm, to have a more realistic approach to the concrete produced by the building industry.

The results showed that with grading optimization and superplasticizer, some crushed rocks can be used for concrete production without increasing, and even decreasing, the cement consumption. This research also contemplated the use of filler. As a mineral admixture it can improve the compressive strength. It can also be used to replace cement; a replacement up to 20 kg/m3 of cement by filler can be done without significant effect on compressive strength.

sted, utgiver, år, opplag, sider
2011. , s. 37
Serie
TRITA-LWR Degree Project, ISSN 1651-064X ; LWR-EX-11-14
Emneord [en]
Crushed rocks, Mortar rheology, Fresh concrete workability, Cement content, Superplasticizer, Filler
HSV kategori
Identifikatorer
URN: urn:nbn:se:kth:diva-96093OAI: oai:DiVA.org:kth-96093DiVA, id: diva2:529528
Utdanningsprogram
Degree of Master - Environmental Engineering and Sustainable Infrastructure
Uppsök
Technology
Veileder
Examiner
Tilgjengelig fra: 2012-05-30 Laget: 2012-05-30 Sist oppdatert: 2012-05-30bibliografisk kontrollert

Open Access i DiVA

fulltext(2631 kB)9265 nedlastinger
Filinformasjon
Fil FULLTEXT01.pdfFilstørrelse 2631 kBChecksum SHA-512
06defefb14cbdd20541e40f900a4528cae7e684145ccc45526a50e36e1fd17c089ed65ec1df87253967a935f2ed69ade4a9a62061e5d1fe0227221602a1860c1
Type fulltextMimetype application/pdf

Av organisasjonen

Søk utenfor DiVA

GoogleGoogle Scholar
Totalt: 9265 nedlastinger
Antall nedlastinger er summen av alle nedlastinger av alle fulltekster. Det kan for eksempel være tidligere versjoner som er ikke lenger tilgjengelige

urn-nbn

Altmetric

urn-nbn
Totalt: 436 treff
RefereraExporteraLink to record
Permanent link

Direct link
Referera
Referensformat
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annet format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annet språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf