A problem with the construction line of business versus the environment is that there are not that much knowledge and rules around the carbon dioxide emissions that several construction projects releases. A lot of companies that we contacted didn´t have the knowledge about the carbon dioxide that releases from the construction projects that they´ve built. This is understandable because it is a very difficult calculation to do, it requires very advanced tools and knowledge around the subject to make detailed calculations. With this master thesis, we want to compare prefabricated buildings with different materials from an environmental perspective with a focus on the carbon dioxide. The different materials we are comparing are steel and tree.   The purpose with this master thesis is to create a basis for Riki AB so that they will have a better sight on the environmental impact from their steel prefabrications which is shipped from China and this will be done with a comparison between a Swedish traditional half prefabricated apartment building.   The first step for the thesis has been a literature study and interviews about the subject. The obtained literature study consists of rapports, relatable thesis, analysis and digital internet sources. The interviews were implemented with companies which were knowledgeable of prefabrication and materials, this was done to get a deeper understanding of the materials effects of the environment.   The result of this examination results that the prefabricated apartment buildings made of steel from China has a larger carbon dioxide emission compared to the Swedish half prefabricated apartment buildings made of tree.

The semiarid region between the North African Savanna and Sahara Desert, known as the Sahel, experienced dramatic multidecadal precipitation variability in the 20th century that was unparalleled in the rest of the world, including devastating droughts and famine in the early 1970s and 80s. Accurate predictions of this region’s hydroclimate future are essential to avoid future disasters of this kind, yet simulations from state of the art general circulation models (GCMs) do a poor job of simulating past Sahel rainfall variability, and don’t even agree on whether future precipitation will increase or decrease under global warming. Furthermore, climate scientists are still not in agreement about whether anthropogenic emissions played an important role relative to natural variability in dictating past Sahel rainfall change. Because the climate system is complex and coupled, it is difficult to determine which processes should be considered causal drivers of circulation changes and which should be considered part of the climate response, and therefore many theories for monsoon rainfall variability coexist in the literature. It is difficult to evaluate these competing theories because observational studies generally cannot be interpreted causally, but simulated experiments may not represent the dynamics of the real world. The Coupled Model Intercomparison Project (CMIP) provides a wealth of data in which GCMs maintained at research institutions worldwide perform similar experiments, allowing the researcher to reach conclusions that are robust to differences in parameterization between GCMs. The scientific community has been using a wide range of statistical techniques to analyze this data, and each has notable limitations. This dissertation explores two statistical techniques for leveraging CMIP to explore the drivers and mechanisms of historical Sahel rainfall variability: analysis of ensemble-mean responses to prescribed variables, and causal inference. In ‎Chapter 1, we give an overview of the climatology and variability of Sahel rainfall and present relevant physical theory. In ‎Chapter 2, we examine the roles of various types of anthropogenic forcing in observations and coupled simulations, using a 3-tiered multi-model mean (MMM) to extract robust climate signals from CMIP phase 5 (CMIP5). We examine “20th century” historical and single-forcing simulations—which separate the influence of anthropogenic aerosols, greenhouse gases (GHG), and natural radiative forcing on global coupled ocean-atmosphere system, and were specifically designed for attribution studies—as well as pre-Industrial control simulations, which only contain unforced internal climate variability, to investigate the drivers of simulated Sahel precipitation variability. The comparison of single-forcing and historical simulations highlights the importance of anthropogenic and volcanic aerosols over GHG in generating forced Sahel rainfall variability that reinforces the observed pattern, with anthropogenic aerosols alone responsible for the low-frequency component of simulated variability. However, the forced MMM only accounts for a small fraction of observed variance. A residual consistency test shows that simulated internal variability cannot explain the residual observed multidecadal variability, and points to model deficiency in simulating multidecadal variability in the forced response, internal variability, or both. In ‎Chapter 3, we investigate the causes for discrepancies in low-frequency Sahel precipitation variability between these ensembles and for model deficiency in reproducing observations. In the most recent version of CMIP – phase 6 of the Coupled Model Intercomparison Project (CMIP6) – the differences between observed and simulated variability are amplified rather than reduced: CMIP6 still grossly underestimates the magnitude of low-frequency variability in Sahel rainfall, but unlike CMIP5, historical mean precipitation in CMIP6 does not even correlate with observed multi-decadal variability. We continue to use a MMM to extract robust climate signals from simulations, but now additionally include sea surface temperature (SST) as a mediating variable in order to test the proposed physical processes. This partitions all influences on Sahel precipitation variability into five components: (1) teleconnections to SST; (2) atmospheric and (3) oceanic variability internal to the climate system; (4) the SST response to external radiative forcing; and (5) the “fast” (not mediated by SST) precipitation response to forcing. Though the coupled simulations perform quite poorly, in a vast improvement from previous ensembles, the CMIP6 atmosphere-only ensemble is able to reproduce the full magnitude of observed low-frequency Sahel precipitation variance when observed SST is prescribed. The high performance is due entirely to the atmospheric response to observed global SST – the fast response to forcing has a relatively small impact on Sahel rainfall, and only lowers the performance of the ensemble when it is included. Using the previously-established North Atlantic Relative Index (NARI) to approximate the role of global SST, we estimate that the strength of simulated teleconnections is consistent with observations. Applying the lessons of the atmosphere-only ensemble to coupled settings, we infer that both coupled CMIP ensembles fail to explain low-frequency historical Sahel rainfall variability mostly because they cannot explain the observed combination of forced and internal variability in SST. Though the fast response is small relative to the simulated response to observed SST variability, it is influential relative to simulated SST variability, and differences between CMIP5 and CMIP6 in the simulation of Sahel precipitation and its correlation with observations can be traced to differences in the simulated fast response to forcing or the role of other unexamined SST patterns. In this chapter, we use NARI to approximate the role of global SST because it is considered by some to be the best single index for estimating teleconnections to the Sahel. However, we show that NARI is only able to explain half of the high-performing simulated low-frequency Sahel precipitation variability in the atmospheric simulations with prescribed global SST. Statistical techniques commonly applied in the literature cannot distinguish between correlation and causality, so we cannot analyze the response of Sahel rainfall to global SST in more depth without atmospheric CMIP simulations targeted at every ocean basin of interest or a new method. In ‎Chapter 4, we turn to a novel technique called causal inference to qualify the notion that NARI can adequately represent the role of global SST in determining Sahel rainfall. We apply a causal discovery algorithm to CMIP6 pre-Industrial control simulations to determine which ocean basins influence Sahel rainfall in individual GCMs. Though we find that state of the art causal discovery algorithms for time series still struggle with data that isn’t generated specifically for algorithm evaluation, we robustly find that NARI does not mediate the full effect of global SST variability on Sahel rainfall in any of the climate simulations. This chapter lays the foundation for future work to fully-characterize the dependence of Sahel precipitation on individual ocean basins using the non-targeted simulations already available in CMIP – an approach which can be validated by comparing the composite results to the interventional historical simulations that are available. Furthermore, we hope this chapter will guide algorithm improvement efforts that are needed to increase the performance and usefulness of time series causal discovery algorithms on climate data.

Coastal ecosystems comprise a relatively small area of the ocean, yet they play a disproportionate role in greenhouse gas (carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O)) and nutrient cycling. Vegetated coastal ecosystems (e.g., mangroves, salt marshes, and seagrasses) are key drivers of coastal greenhouse gas and nutrient cycling because of their environmental characteristics (e.g., shallow depths, organic matter rich sediments, etc.). My dissertation addresses the role of vegetated coastal ecosystems in greenhouse gas budgets and biogeochemical cycling. In Chapter 1, I conducted a meta-analysis to quantify the global emissions of CH4 from mangrove, salt marsh, and seagrass ecosystems. Here I show that mangrove ecosystems contribute the most CH4 out of these vegetated areas to the global marine CH4 budget. Further, while a well-known negative relationship between salinity and CH4 fluxes exists for salt marshes globally, this relationship does not hold for mangrove or seagrass meadows, suggesting that other environmental drivers are more important for predicting CH4 fluxes in these ecosystems. In Chapter 2, I present in situ fluxes of CH4 and N2O across the sediment-water interface as well as air-sea fluxes in seagrass meadows and adjacent non-vegetated sediments in two temperate coastal lagoons. Here I demonstrate that seagrass meadows can be sources or sinks of CH4 and that N2O uptake can enhance carbon sequestration in seagrass meadows by ~10%. In Chapter 3, I quantify fluxes of dissolved inorganic carbon, nitrogen, and phosphorous across the sediment-water interface in seagrass meadows and adjacent non-vegetated sediments in the same two coastal lagoons. I found that both seagrass and non-vegetated sediments exhibited dissolved inorganic carbon emission and denitrification, and that dissolved inorganic phosphorous fluxes varied by site and not with vegetation presence. This dissertation highlights the dynamic role coastal ecosystems play in biogeochemical cycling and the importance of vegetated coastal ecosystems in coastal greenhouse gas budgets. / 2024-10-03T00:00:00Z

Traffic signal cycle lengths are traditionally optimized to minimize vehicle delay at intersections using the Webster formulation. This thesis includes two studies that develop new formulations to compute the optimum cycle length of isolated intersections, considering measures of effectiveness such as vehicle delay, fuel consumption and tailpipe emissions. Additionally, both studies validate the Webster model against simulated data. The microscopic simulation software, INTEGRATION, was used to simulate two-phase and four-phase isolated intersections over a range of cycle lengths, traffic demand levels, and signal timing lost times. Intersection delay, fuel consumption levels, and emissions of hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NOx), and carbon dioxide (CO2) were derived from the simulation software. The cycle lengths that minimized the various measures of effectiveness were then used to develop the proposed formulations. The first research effort entailed recalibrating the Webster model to the simulated data to develop a new delay, fuel consumption, and emissions formulation. However, an additional intercept was incorporated to the new formulations to enhance the Webster model. The second research effort entailed updating the proposed model against four study intersections. To account for the stochastic and random nature of traffic, the simulations were then run with twenty random seeds per scenario. Both efforts noted its estimated cycle lengths to minimize fuel consumption and emissions were longer than cycle lengths optimized for vehicle delay only. Secondly, the simulation results manifested an overestimation in optimum cycle lengths derived from the Webster model for high vehicle demands. / Master of Science

Yes / The increasing concentration of carbon dioxide (CO2) in the atmosphere is a primary global environmental concern due to its detrimental impacts on climate change. A significant reduction in CO2 generation together with its capture and storage is an imperative need of the time. CO2 can be captured from power plants and other industries through various methods such as absorption, adsorption, membranes, physical and biological separation techniques. The most widely used systems are solvent based CO2 absorption method. The aim of this study was to analyze the effect of various random and structured packing materials in absorption column on CO2 removing efficiency. Aspen plus was used to develop the CO2 capture model for different packing materials with Monoethanolamine (MEA) solvent in order to optimize the system. It was found that the lowest re-boiler duty of 3,444 kJ/KgCO2 yield the highest rich CO2 loading of 0.475 (mole CO2/mole MEA) by using the BX type of structured packing having the highest surface area. The surface area of the different packing materials were inversely proportional to the temperature profiles along the column. Furthermore, the packing materials with higher surface areas yielded higher CO2 loading profiles and vice versa. The findings of this study and recommendation would help further research on optimization of solvent-based CO2 capturing technologies.

Yes / It has been globally recognized as necessary to reduce greenhouse gas (GHG) emissions for mitigating the adverse effects of global warming on earth. Carbon dioxide (CO2) capture and storage (CCS) technologies can play a critical role to achieve these reductions. Current CCS technologies use several different approaches including adsorption, membrane separation, physical and chemical absorption to separate CO2from flue gases. This study aims to evaluate the performance and energy savings of CO2capture system based on chemical absorption by installing an intercooler in the system. Monoethanolamine (MEA) was used as the absorption solvent and Aspen HYSYS (ver. 9) was used to simulate the CO2capturing model. The positioning of the intercooler was studied in 10 different cases and compared with the base case 0 without intercooling. It was found that the installation of the intercooler improved the overall efficiency of CO2recovery in the designed system for all 1-10 cases. Intercooler case 9 was found to be the best case in providing the highest recovery of CO2(92.68%), together with MEA solvent savings of 2.51%. Furthermore, energy savings of 16 GJ/h was estimated from the absorber column alone, that would increase many folds for the entire CO2capture plant. The intercooling system, thus showed improved CO2recovery performance and potential of significant savings in MEA solvent loading and energy requirements, essential for the development of economical and optimized CO2capturing technology.

Carbon (C) biogeochemical cycling studies in northern peatlands, in particular the production, consumption, storage and emission of C gases (CO2 and CH4) over space and time between different peatland landforms can help in understanding their current and future role in the global C cycle. In some peatlands, a distinct surface patterning of vegetation, interspersed with open water pools, controls the spatial and temporal variability in CO 2 and CH4 exchange to atmosphere. These open water pools initially develop from shallow, flooded hollows to deeper water bodies and at some point reach a limit in their depth. Observations link pool size to age and spatial location on the peatland surface and over time the proportional cover of pools increases, playing an important role in the long-term peatland C balance. / The processes responsible for the production of CO2 and CH 4 in pools remain unexplored. In particular, the contribution of pools to the peatland C balance over the timeframe of the development of a pool complex is not explained and pools are not incorporated into current peatland models. A field study was carried out to examine the exchange of CO2 and CH4 from pools to atmosphere and to explore the spatial and temporal dynamics in CO2, CH4 and DOC storage in pools of different size and spatial location. This was undertaken to improve the understanding of the processes responsible for the generation of CO 2 and CH4 over the timescale of pool development. The empirical study was carried out during spring, summer and fall over two years in an ombrotrophic, raised bog, Quebec, Canada. A modelling component was carried out to examine the contribution of pools to the long-term peatland C balance. / Measurements of dissolved concentrations and emissions of CO2 and CH4 from pool surfaces to atmosphere were different among pools of different sizes and spatial location. Shallow pools had consistently higher emissions of both CO2 and CH4 and higher water column dissolved CO2 and DOC concentrations. Deeper pools had greater concentrations of sediment CH4. Dissolved organic carbon in pools was allochthonous, with a greater concentrations and proportion from higher plant materials in shallow pools, likely contributing to the observed water column CO2 concentrations and greater CO2 emissions. / All pools were supersaturated with dissolved CO2 and CH 4 at the time of sampling, with shallow pools up to eight times atmospheric equilibrium concentrations for CO2 and concentrations were up to one hundred times greater than CH4, comparable to findings in other global freshwater systems. Results suggest that greater decomposition is occurring in shallow pools due to warmer water and basal sediment temperatures and increased light penetration and dissolved oxygen (00) and that greater CH4 production and oxidation accounts for some of the differences reaching a limit at 0.7 m deep. Even though this range of pools are not as deep as pools found on other northern peatlands, the results provide evidence for the potential processes responsible for the generation of CO2 and CH4 emissions to atmosphere and demonstrate that pools have a significant role in the short and long-term peatland C balance. Modelling the hypothesised processes responsible for the generation of CO2 and CH4 shows that if sediment decomposition is the major source of these gases then the dynamical link between pool sediments, C gas production and pool growth has been demonstrated. Ultimately their role as source or sink is largely determined by their size (depth), the proportional cover on the landscape and their rates of C storage in sediments versus rates of C uptake and exchange.

No description available.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Carbon dioxide (CO2) is seen as one of the main contributors to global warming. The use of fossil fuels for power production leads to large quantities of carbon dioxide being released into the atmosphere. The released CO2 can, however, be captured by retrofitting capture units downstream from the power plant called Post Combustion Carbon Dioxide Capturing. Post combustion CO2 capture can involve the reactive absorption of CO2 from the power plant flue gas steam. Reactive solvents, such as monoethanolamine (MEA), are used for capturing the CO2 and the solvent is regenerated in a desorber unit where the addition of heat drives the reverse reaction, releasing the captured CO2. However, the large energy requirement for solvent regeneration reduces the viability of employing CO2 capture on an industrial scale. This study focused on establishing a facility for CO2 capture studies – the main aim being the construction and validation of the results produced by the pilot plant facility. A secondary aim of this study was developing an Aspen Plus® Simulation method that would simplify simulating the complex CO2 capture process. Results from the simulation were to be compared to that of the pilot plant experiments. A pilot plant facility with a closed gas system, allowing gas recycling from both the absorber and the stripping columns, was set up. The absorber column (internal diameter = 0.2 m) was set up to allow one to obtain information regarding gas- and liquid temperatures and compositions at various column heights. Online gas analysers are used for analysing the gas composition at various locations in the absorber column. The pilot plant was initially commissioned with 20 weight % MEA in aqueous solution; however the main validation experiments were conducted with 30 weight % MEA in aqueous solution. 30 weight % MEA (aq) is generally used as the reference solvent for pilot plant studies. Pilot plant results with regards to the carbon dioxide concentration profiles for the absorber column as well as the regeneration energy requirement and capture rates compared well to literature data. The Aspen Plus® simulation was also set up and validated using published pilot plant data. The comparison of the pilot plant results from this study, to the results from the Aspen Plus® Simulation, showed good agreement between the two. The Aspen Plus® Simulation could further be used to validate pilot plant data that has been gathered outside the range of reported CO2 capture efficiencies. The Aspen Plus®model was evaluated at liquid-to-gas ratios of 1.7 and regeneration energies matching the pilot plant results. It was found that the model under predicts the capture efficiency of CO2 with an average of 4.0%. The model was corrected for this error at liquid-to-gas ratios of 2 and the fit of the model to pilot plant results improved considerably (R2-value = 0.965). Pilot plant repeatability was investigated with both 20 weight %- and 30 weight % MEA in aqueous solution. Temperature- and gas concentration profiles from the absorber column showed good repeatability. The maximum deviation of the regeneration energy and the capture efficiency from the calculation means were ±0.72% and ±1.40% respectively. The aims of this study have been met by establishing, and validating the results of a pilot plant facility for carbon dioxide capture studies. It has been shown that the pilot plant produces repeatable results. Results from the Aspen Plus® Simulation were validated and also match results from the established pilot plant setup. The simulation may prove to provide valuable information regarding the optimal operating conditions for the pilot plant and may aid in performing a full parametric study on the CO2 capture process. / AFRIKAANSE OPSOMMING: Koolstofdioksied (CO2) word geklassifiseer as een van die bekendste kweekhuisgasse wat ʼn groot bydra lewer tot aardverwarming. Die gebruik van fossielbrandstowwe om na die energiebehoeftes van die mens om te sien lei daartoe dat groot hoeveelhede koolstofdioksied, hoofsaaklik vanaf kragstasies, vrygestel word in die atmosfeer. Daar is verskeie maniere hoe die CO2 uit die uitlaatgas van kragstasies verwyder kan word – die vernaamste hiervan is bekend as die Na-verbranding opvangs metode. Die opvangs van CO2 na verbranding van fossielbrandstowwe vir kragproduksie kan vermag word deur van reaktiewe absorpsie tegnieke gebruik te maak. Mono-etanol-amien (MEA) kan vir hierdie doeleindes aangewend word deur dit, in ʼn absorpsiekolom, in kontak te bring met die CO2. Die gereageerde oplosmiddel word geregenereer deur die oplosmiddel te verhit in ʼn stropingskolom. ʼn Bykans suiwer CO2 stroom word vrygestel. Die implementering van hierdie opvangtegniek op industriële skaal lei egter tot groot energieverliese vir die kragstasies. Die hoofrede hiervoor is die hoeveelheid energie wat benodig word om die oplosmiddel te regenereer vir hergebruik. Die hoofdoel van hierdie studie was gemik op die oprigting en inwerkstelling van 'n navorsingsfasiliteit vir studies aangaande die na-verbranding opvangs van CO2. Dit het behels die ontwerp, konstruksie en stawing van gelewerde resultate met resultate in die literatuur. 'n Sekondêre doel van hierdie studie was die metode-ontwikkeling vir die opstel van 'n Aspen Plus® Model wat die simulasie van die CO2 opvangsproses met ʼn reaktiewe oplosmiddel, MEA, vereenvoudig. Gesimuleerde resultate is vergelyk met resultate uit die literatuur. Die toetsaanleg, met 'n geslote gas stelsel, maak voorsiening vir die hersirkulering van gas wat vir eksperimentele doeleindes gebruik word. Die absorpsie kolom (interne diameter van 0,2 m) is opgestel sodat informasie aangaande die gas- en vloeistof temperature, sowel as gas- en vloeistof komposisies vanaf verskillende kolomhoogtes, bekom kan word. ʼn Aanlyn CO2 analiseerder word gebruik om vir CO2 in die prosesgas te analiseer. Die toetsaanleg is aanvanklik in bedryf gestel met ʼn 20 massa % MEA in waterige oplossing; die hoof eksperimente is egter uitgevoer deur van 30 massa % MEA in waterige oplossing gebruik te maak. Die laasgenoemde oplosmiddel word algemeen gebruik in die CO2 opvangs verwante navorsingsveld. Die resultate van die toetsaanleg, vergelyk goed met resultate in die literatuur. Die gesimuleerde Aspen Plus® resultate is ook vergelyk met resultate in die literatuur en die gevolgtrekking is gemaak dat die simulasie gebruik kan word om redelike akkurate voorspellings van die werklike prosesresultate te gee. Die simulasie is verder ook gebruik om resultate, verkry vanaf die opgerigte toetsaanleg, te verifieer en ʼn goeie ooreenstemming tussen die gesimuleerde en die eksperimentele resultate is waargeneem. ʼn Verder gevolgtrekking aangaan die Aspen Plus® simulasie metode was dat dit in die toekoms ʼn groot doel kan dien in die optimeringsproses van toetsaanlegte waar navorsing aangaande die na-verbranding opvang van CO2 gedoen word. Die Aspen Plus® model is geëvalueer by ‘n vloeistof-tot-gas-verhouding van 1,7 en ooreenstemmende toetsaanleg resultate, aangaande die hoeveelheid energie wat ingesit is vir die regenerasie van die oplosmiddel. Die onakkuraathede in die model, met betrekking tot die voorspelling van die hoeveelheid CO2 wat vasgevang sal word, is hierdeur bepaal en die model is daarvoor aangepas. Resultate van die verbeterde model vergelyk baie goed met die toetsaanleg resultate – ʼn R2-waarde van 0.965. Die herhaalbaarheid van die toetsaanleg resultate is ondersoek en ʼn goeie herhaalbaarheid van die temperatuur- en CO2 konsentrasieprofiele is verkry. Die toetsaanleg dui ook goeie herhaalbaarheid met betrekking tot die effektiwiteit waarmee die CO2 uit ʼn gasstroom verwyder word (± 1,40%), sowel as die hoeveelheid energie wat benodig word vir regenerering van die oplosmiddel (± 0,72%). Die doelwitte van hierdie studie is bereik deur die oprigting en verifiëring van resultate gelewer deur 'n toetsaanleg vir studies aangaande die na-verbrandingsopvang van CO2. Die herhaalbaarheid van toetaanleg resultate is bewys. Resultate van die Aspen Plus® simulasie stem ooreen met resultate in die literatuur sowel as resultate van die toetsaanleg wat opgerig is in hierdie studie.

Thesis (MScEng)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: The UNFCCC (United Nations Framework Convention on Climate Change), enabled by the Kyoto Protocol, set enforced responsibilities on industrialised countries to reduce the amount of emissions (greenhouse gases) produced. This global call for the reduction of greenhouse gas emissions ensured that the manufacturing sector commit to emission reduction. The asphalt industry has embarked on a quest to find alternative methods of producing and constructing asphalt mixes which will release less greenhouse gasses into the atmosphere. These new methods include the reduction in production and construction temperatures which in turn will reduce the amount of greenhouse emissions produced. These new methods introduced the concept of warm mix asphalt (WMA) to the alternative hot mix asphalt (HMA). To produce a WMA mix at lower temperatures the binder needs to be in a workable state so to effectively coat the aggregate and produce a good quality mix. WMA technologies have been developed to enable production of mixes at lower temperatures (effectively reducing emissions) whilst retaining the required binder viscosity and properties needed to produce a quality mix. The question which needs to be answered is whether the performance of these WMA mixes can compare with that of HMA mixes. In this study several WMA mixes (with different WMA technologies) are evaluated against their equivalent HMA mixes in terms of fatigue life and flexural stiffness. Phase angle results were also considered. Flexural stiffness is a mix property which is dependent on loading time and temperature. It is used to measure the load spread ability of a mix and also influences fatigue behaviour. Fatigue cracking occurs in the material as a result of repeated cyclic loading. The evaluation and analysis conducted in this study show that WMA mixes can compare favourably and even exceed that of HMA mixes in certain cases, although some WMA mixes resulted in lower fatigue life or flexural stiffness than its corresponding HMA mixes, which could be attributed to differences in mix components and variables. In this study a literature study, methodology, laboratory test results, a comparison of mix results and conclusions and recommendations are made. / AFRIKAANSE OPSOMMING: Die UNFCCC (United Nations Framework Convention on Climate Change) was in staat gestel deur die Kyoto Protocol om verantwoordelikhede op geïndustrialiseerde lande te forseer om die hoeveelheid van nadelige kweekhuisgasse wat geproduseer word te verminder. Hierdie globale oproep tot die vermindering van kweekhuisgasse verseker dat die vervaardigingsektor hulself verbind tot emissie vermindering. Die asfalt industrie het begin met 'n soektog na alternatiewe metodes van vervaardiging en die bou van asfaltmengsels wat minder kweekhuisgasse sal vrystel in die atmosfeer. Hierdie nuwe metodes sluit die vermindering in produksie en konstruksie temperature in wat op sy beurt die hoeveelheid kweekhuisgasse geproduseer verminder. Hierdie nuwe metodes het die konsep van warm mengsel asfalt (WMA) bekendgestel teenoor die alternatiewe ‘hot’ mengsel asfalt (HMA). Om ‘n WMA mengsel te produseer by laer temperature, moet die bindmiddel in 'n werkbare toestand wees om die aggregaat heeltemal te bedek en 'n goeie gehalte mengsel te produseer. WMA tegnologie is ontwikkel om die produksie van mengsels teen laer temperature te realiseer (vermindering die uitlaatgasse), terwyl die vereiste bindmiddel viskositeit en eienskappe wat nodig is om 'n kwaliteit mengsel te produseer behou word. Die vraag wat beantwoord moet word, is of die prestasie van hierdie WMA mengsel kan vergelyk word met dié van HMA mengsel. In hierdie studie is 'n paar WMA mengsels (met verskillende WMA tegnologie) geëvalueer teen hul ekwivalent HMA mengsels in terme van vermoeiing en buig styfheid. Fase hoek resultate is ook in ag geneem. Buig styfheid is 'n mengsel eienskap wat afhanklik is van die laai tyd en temperatuur. Dit word gebruik om die las verspreiding vermoë van 'n mengsel te meet en beïnvloed ook vermoeiing gedrag. Vermoeidheid krake kom voor in die materiaal as gevolg van herhaalde sikliese laai. Die evaluering en ontleding in hierdie studie toon dat WMA mengsels goed vergelyk en selfs in sekere gevalle meer as dié van HMA mengsels, hoewel sommige WMA mengsels laer vermoeidheid lewe of buig styfheid as die ooreenstemmende HMA mengsels gewys het, wat toegeskryf kan word tot verskille in mengsel komponente en veranderlikes. In hierdie studie word 'n literatuurstudie, metodiek, laboratorium toets resultate, 'n vergelyking van die mengsel resultate en gevolgtrekkings en aanbevelings gemaak.