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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Sustainable mass handling : Modelling quantities of excavated soil and rock in residential construction projects

Israelsson, Filip January 2014 (has links)
An efficient handling process of aggregates and excavated soil and rock will be of increasing importance in expanding urban regions. The construction of residences, infrastructure and commercial areas generate significant amounts of soil and rock that can be re-used more efficiently as construction material, minimizing transportation and environmental impact. A key element is the implementation of central intermediate storage sites for re-use purposes and cooperation between several construction projects in a region. The evaluation of storage capacities and optimal site locations is in turn dependent on comprehensive knowledge about what quantities of aggregates and excavated soil and rock that will be generated and utilized in the region. The calculation model presented in this thesis provides a way of estimating the amount of excavated soil and rock generated during the construction of new residential areas at an initial stage of the planning process. The excavated volume is expressed as a function of the number of residents and the number of floors in the buildings of the planned area, allowing for an early estimation that may effectively influence the logistical planning of the mass handling process. The simplified calculation model applied to a case study of the existing residential area Annedal in Stockholm produces an estimated amount of 577 500 ton excavated soil and rock, approximately 3.8 % lower than the reference value of 600 000 ton. Regional storage sites are advantageous as different construction projects generate and utilize different types of soil, rock and aggregates, resulting in a higher possible re-use share than in individual projects. When regarding the energy usage in transportation, it is shown that intermediate storage sites located within 10 km of the construction site may allow for more than 15 % energy reduction if re-using 25 % of the excavated amount of soil and rock. A distance of 5 km may yield more than 20 % reduction of transportation energy for the same share of re-use.
2

Vägprojekt ur ett klimatpåverkansperspektiv : - En fallstudie om potentiella klimatåtgärder

Ejekrans, Ida, Hjertbro, Alexandra January 2021 (has links)
Uppdragsgivare för examensarbetet är Skanska Sverige AB, Region Mellansverige väg- och anläggning. Examensarbetets centrala del handlar om klimatpåverkan, en fallstudie görs mot ett pågående väg- och anläggningsprojekt för att studera projektets växthusgasutsläpp. Syftet är att analysera stora klimatbelastande faktorer i projektet samt diskutera och lyfta fram potentiella åtgärder för klimatbesparing. Författarna har tagit del av Skanskas interna klimatkalkyl som kartlägger miljöutsläpp hos projektet. Utifrån klimatkalkylens poster granskades de stora, relevanta och påverkbara utsläppen. Grävmaskiner och dumper har en sammanlagd andel på 30 % av projektets totala andel växthusgasutsläpp. Dessa maskiner drivs idag med fossil diesel och låginblandad RME. Att byta drivmedel till HVO100 medför en reducering av växthusgasutsläpp med 71 % för maskinerna och sänker projektets totala utsläpp med 20 % vilket är den åtgärd som ger bäst resultat. Även ett drivmedelsskifte till 100 % RME ger en 48 % reducering av maskinernas utsläpp och sänker hela projektets utsläpp med 13 %. Examensarbetet lyfter problematiken angående den bristande tillgången till hållbara råvaror för biodrivmedelsproduktion och presenterar forskning för framtida råvarupotentialer. Hur massor hanteras i ett vägprojekt har stor betydelse för byggskedets klimatpåverkan. Skanska har i projektet återanvänt en del av schaktmassorna och gamla betonggrunder som utfyllnadsmaterial samt fräst upp asfalt och återanvänt det som bärlager i uppbyggnaden för ny väg. Den sammanlagda besparingen för dessa tre åtgärder är cirka 4 % av projektets totala växthusgasutsläpp. Hade återstående mängd fall A-massor återanvänts hade besparingen ökat med cirka 10 % av projektets totala växthusgasutsläpp. Slutsatsen är att det finns potential att reducera utsläppen i projektet tack vare byte av drivmedel samt återanvändning av schaktmassor. / The client for the degree project is Skanska Sweden AB, Region Central Sweden Road and Construction. The central part of the thesis is about climate impact, a case study is carried out against an ongoing road and construction project to study the project's greenhouse gas emissions. The aim is to analyze major climate-burdening factors in the project and to discuss and highlight potential measures for climate saving. The authors have taken note of Skanska’s internal climate calculation that map environmental emissions at the project. Based on the items of the climate calculation, the large, relevant, and avoidable emissions were examined.  Excavators and dump trucks have a total share of 30 % of the project's total share of greenhouse gas emissions. The machines are currently powered by fossil diesel and low-mix RME. Changing fuel to HVO100 results in a reduction of greenhouse gas emissions by 71% for the machines and reduces the project's total emissions by 20%, which is the measure that gives the best results. Even a fuel shift to 100% RME provides a 48% reduction of the machines emissions and lowers the entire project's emissions by 13%. The degree project lifts the problem regarding the lack of access to sustainable raw materials for biofuel production and presents research for future commodity potentials.  How masses are handled in a road project is of great importance for the climate impact of the construction phase. In the project, Skanska has reused some of the excavation rubble and old concrete foundations as fillers and milled up asphalt and reused it as a bearing in the construction for a new road. The total saving for these three measures is approximately 4 % of the project's total greenhouse gas emissions. Had the remaining amount of case A-masses been reused, the savings would have increased by about 10 % of the project's total greenhouse gas emissions.  The conclusion is that there is potential to reduce emissions in the project thanks to the change of fuel and reuse of excavation rubble.

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