<p>Research on freeze-thaw resistance of concrete in general and on curing and moisture conditions in particular is motivated from an economic and product sustainability point of view. Specifically, it is argued for the importance of considering the effect of curing and test exposure conditions on the moisture uptake and performance during freeze-thaw. Due to the demonstrated importance of moisture conditions on performance, they should be related to those of field service conditions when choosing a test procedure in a particular case. This is vital for adequate testing of new</p><p>and more sustainable concrete materials.</p>

<p>Kostnaderna för fuktskador i Sverige uppskattas årligen uppgå till mångmiljard belopp.</p><p>Fuktskador i byggnader medför också en ökad risk för ohälsa hos brukarna. Kunskapen för</p><p>att producera fuktsäkra byggnader finns men utnyttjas inte i den omfattning den borde.</p><p>Den 1 juli 2007 träder en ny upplaga av Boverkets byggregler i kraft. Förtydliganden har</p><p>gjorts i avsnittet gällande fukt, vilka underlättar verifieringen av entreprenadens</p><p>fuktsäkerhet. Reglerna innefattar också krav på kritiska fukttillstånd i material. Denna studie</p><p>syftar till att kartlägga brister i produktionsskedet och hur produktionen kan utvecklas för att</p><p>motsvara de i Boverkets byggregler ställda krav på fuktsäkerhet.</p><p>Intervjuer har förts med olika representanter i byggbranschen för att ge en helhetssyn av</p><p>fuktproblematiken. Göran Hedenblad vid Boverket menar att tillsynen och kontrollen av</p><p>fukt kan och måste bli bättre på byggarbetsplatsen. Fuktkonsulten Tord Nilsson hävdar att</p><p>de nya kraven innebär ett paradigmskifte som medför stora förändringar på dagens sätt att</p><p>producera byggnader. De intervjuer som gjordes med beställare och entreprenör visar dock</p><p>på både bristande fuktkunskap och bristande strategi för att nå ett fuktsäkert byggande.</p><p>Vid fältstudien påvisades brister i produktionen med avseende på skydd av material och</p><p>konstruktion, uttorkning och utförandet av fuktkvotsmätningar. Många av dessa brister</p><p>härrör från att fuktproblematiken inte har en central roll vare sig i program-, projekteringseller</p><p>produktionsskedet. Vidare konstateras att kunskapsnivån för att hantera fukt kan</p><p>utvecklas hos all personal och i alla delar av byggprocessen.</p><p>Av de observationer som gjorts under fältstudien har åtgärdsförslag till en ökad fuktsäkerhet</p><p>sammanställts i rapporten. Vidare har ett informationsblad utarbetats för att informera om</p><p>fukt och dess skadeverkningar samt att ge några förslag till åtgärder som kan förbättra</p><p>fukthanteringen ute på byggarbetsplatsen. Informationsbladet bör placeras på</p><p>byggarbetsplatsen för att stödja entreprenören i sitt fuktsäkringsarbete.</p><p>Eftersom ramverket för projektet är fastslaget då produktionsfasen tar vid innebär detta</p><p>begränsningar för fuktsäkerhetsarbetet. För att skapa bättre förutsättningar för en fuktsäkrare</p><p>produktion anser vi att en fuktsakkunnig skall anlitas så tidigt som möjligt i projektet.</p> / <p>The costs regarding moisture damages in buildings in Sweden are expected to reach several</p><p>billions SEK each year. These moisture damages also result in an increased risk regarding</p><p>health issues among the users. The knowledge of how to produce moisture secure buildings</p><p>exists, but it is not beeing used to the extent it could be.</p><p>The first of July 2007 a new edition of Boverket´s regulations regarding buildings takes</p><p>effect. Boverket is the Swedish board of housing, building and planning. Clarifications have</p><p>been made concerning moisture issues which facilitate the verifications of moisture security</p><p>in the chain of building production. The regulations also contain demands according to</p><p>critical levels of moisture in building materials. This study is meant to survey errors in the</p><p>production phase and how the production can develop to correspond to the regulations stated</p><p>by Boverket regarding moisture safety.</p><p>We interviewed different representatives in the building sector to give a general impression</p><p>of the moisture issues. Göran Hedenblad at Boverket states that the supervision and control</p><p>regarding moisture on the construction site can and must be improved. The moisture</p><p>consultant Tord Nilsson believes that the new demands will result in huge changes</p><p>concerning the way buildings are produced. The interviews carried out with the future</p><p>proprietor and the contractor displayed a lack of knowledge and strategy concerning how to</p><p>produce moisture secure structures.</p><p>The field study pointed out incongruities concerning how building materials and the</p><p>constructions were protected from moisture influence, evaporation and the control of the</p><p>moisture levels in the structure. Many of these flaws originate from the fact that moisture</p><p>issues are not a central matter, neither in the phase of planning nor production. Further it can</p><p>be established that the level of knowledge regarding how to deal with moisture problems can</p><p>be developed among all personnel and sectors in the building process.</p><p>The observations implemented during the field study have resulted in several preventive</p><p>measures which are compiled in this thesis. Further has an information sheet been put</p><p>together with the purpose to inform about these preventive measures and the damages</p><p>moisture inflicts upon structures and human beings. The information sheet should be placed on the construction site to support the contractors in their work for a more moisture safe</p><p>production.</p>

Based on the determination of the zero-flux plane, a water balance procedure for large-scale experimental databases was automated to estimate the soil water balance based on soil water content distribution with depth through time. The automated procedure was verified using data from the BOREAS project obtained in three Intensive Field Campaigns during the spring and summer of 1994. The data used correspond to four tower sites measuring atmospheric fluxes above the forest canopy from the Northern and Southern Study Areas and are designated according to the predominant vegetation in the area as Old Jack Pine and Young Jack Pine. The total hydraulic head through time at these sites is determined to identify the position of the zero-flux plane, which separates that part of the soil profile in which water flow is upward from the region in which the water flow is downward. In conjunction with precipitation and soil water content data, the procedure allows estimation of the actual soil water balance, the water used from the region above the zero-flux plane being evapotranspiration, and the change in soil water content below the mean zero-flux plane being drainage. Prior to this study, no published attempt had been made to automate a water balance procedure for large-scale experimental databases based on the position of the zero-flux plane and soil water content distribution through time. / Graduation date: 1997

Dry land agriculture using summer fallow is a common crop production practice in the Columbia Plateau region of eastern Oregon. Farmed-over level terraces are used to control surface water runoff and soil erosion. More than 70 percent of the average annual precipitation around Pendleton, Oregon (350 - 400 mm) falls as low intensity, long duration rainfall from September to March. Wetter soil zones typically occur above and below the terrace. These areas have a higher potential for crop production as well as for movement of chemicals to ground water and to surface water where seepage occurs. The extra nitrogen or water that could accumulate in these areas needs to be considered in managing these areas. The first objective of this study was to measure the distribution of nitrate nitrogen (NO���-N) and water in relation to farmed-over level terraces, and infer potential solute flow patterns from changes in the measured distributions over time. The second objective was to make recommendations regarding management practices required for specific field locations to maximize crop production and minimize negative impacts on groundwater quality. Results indicate NO������ concentrations following harvest were < 4 mg kg����� of soil. Equivalent to soil solution concentrations between 27 and 20 mg L����� at 15 and 20 percent volumetric water content, respectively. Limited deep percolation of NO������ occurred below the root zone between harvest and planting. The NO������ concentrations below the root zone were < 1 to 15 mg kg����� following the summer fallow period. In August 1993, evidence exists that shows N applied fertilizer moved out of the surface 0.3 m and deeper into the profile. The redistribution of NO������ in the terrace channels of transects 1 and 2 strongly support this. Soil profiles that contain high residual concentrations of NO���-N during the fallow period increase the potential for NO���-N leaching below the root zone. Unusually heavy precipitation during normally dry periods or above normal winter precipitation increases the potential for NO���-N leaching below the root zone. / Graduation date: 1995

Surface mining is a major industry in eastern Tennessee that removes much of the native forest. To restore the forest, reclamation practices are used. These include planting a ground cover species with native hardwoods. Competition between the ground cover and tree species for soil resources could hinder growth and decrease survival of the trees. Northern red oak (Quercus rubra) was used for this study to examine the possible effects of this competition and the relationships between root growth and soil moisture through a field and a greenhouse experiment. A field experiment was designed using four different ground cover treatments (Soldiago nemoralis, Medicago sativa, Panicum virgatum, and bare ground) with four different hardwood species. Northern red oak was measured for this study. The results showed that the site physical factors (slope position, soil temperature, and soil moisture) were not related to each other. Soil moisture varied by depth with the lower depths (46 cm to 76 cm) was much higher than the upper depths (0 to 46 cm). Root growth did not differ by treatment or percent cover. Both soil temperature and ground cover percentage increased over the growing season. Root growth showed a relationship with depth with the upper depths of soil having more roots than the lower depths. Annual rye was used as well as switchgrass, alfalfa, and bare ground treatments for a green house study. Two-year-old Northern red oak seedlings were first planted in pots and then ground covers were established and grown for 9 weeks. Then water stress was imposed over two dry down periods during which transpiration and soil moisture were measured. Root growth was measured after harvest. The results showed a relationship between transpiration and soil moisture. Soil moisture was highest in the bare ground treatment and lowest in the annual rye treatment. Fine root development of trees was greatest in the bare and alfalfa and lowest in the annual rye. Switchgrass had the second highest soil moisture and third highest fine root development. Root growth was related to both soil moisture and transpiration.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 113-121).

Soil moisture is a key state variable that controls runoff formation, infiltration and partitioning of radiation into latent and sensible heat. However, the experimental characterisation of near surface soil moisture patterns and their controls on runoff formation remains a challenge. This subject was one aspect of the BMBF-funded OPAQUE project (operational discharge and flooding predictions in head catchments). As part of that project the focus of this dissertation is on: (1) testing the methodology and feasibility of the Spatial TDR technology in producing soil moisture profiles along TDR probes, including an inversion technique of the recorded signal in heterogeneous field soils, (2) the analysis of spatial variability and temporal dynamics of soil moisture at the field scale including field experiments and hydrological modelling, (3) the application of models of different complexity for understanding soil moisture dynamics and its importance for runoff generation as well as for improving the prediction of runoff volumes. To fulfil objective 1, several laboratory experiments were conducted to understand the influence of probe rod geometry and heterogeneities in the sampling volume under different wetness conditions. This includes a detailed analysis on how these error sources affect retrieval of soil moisture profiles in soils. Concerning objective 2 a sampling strategy of two TDR clusters installed in the head water of the Wilde Weißeritz catchment (Eastern Ore Mountains, Germany) was used to investigate how well “the catchment state” can be characterised by means of distributed soil moisture data observed at the field scale. A grassland site and a forested site both located on gentle slopes were instrumented with two Spatial TDR clusters that consist of up to 39 TDR probes. Process understanding was gained by modelling the interaction of evapotranspiration and soil moisture with the hydrological process model CATFLOW. A field scale irrigation experiment was carried out to investigate near subsurface processes at the hillslope scale. The interactions of soil moisture and runoff formation were analysed using discharge data from three nested catchments: the Becherbach with a size of 2 km², the Rehefeld catchment (17 km²) and the superordinate Ammelsdorf catchment (49 km²). Statistical analyses including observations of pre-event runoff, soil moisture and different rainfall characteristics were employed to predict stream flow volume. On the different scales a strong correlation between the average soil moisture and the runoff coefficients of rainfall-runoff events could be found, which almost explains equivalent variability as the pre-event runoff. Furthermore, there was a strong correlation between surface soil moisture and subsurface wetness with a hysteretic behaviour between runoff soil moisture. To fulfil objective 3 these findings were used in a generalised linear model (GLM) analysis which combines state variables describing the catchments antecedent wetness and variables describing the meteorological forcing in order to predict event runoff coefficients. GLM results were compared to simulations with the catchment model WaSiM ETH. Hereby were the model results of the GLMs always better than the simulations with WaSiM ETH. The GLM analysis indicated that the proposed sampling strategy of clustering TDR probes in typical functional units is a promising technique to explore soil moisture controls on runoff generation and can be an important link between the scales. Long term monitoring of such sites could yield valuable information for flood warning and forecasting by identifying critical soil moisture conditions for the former and providing a better representation of the initial moisture conditions for the latter. / Abflussentwicklung, Infiltration und die Umverteilung von Strahlung in latenten und sensiblen Wärmestrom werden maßgeblich durch die Bodenfeuchte der vadosen Zone gesteuert. Trotz allem, gibt s wenig Arbeiten die sich mit der experimentellen Charakterisierung der Bodenfeuchteverteilung und ihre Auswirkung auf die Abflussbildung beschäftigen. Der Fokus dieser Dissertation wurde darauf ausgerichtet: (1) die Methode des Spatial TDR und deren Anwendbarkeit einschließlich der Inversion des TDR Signals in heterogenen Böden zu prüfen, (2) die Analyse der räumlichen und zeitlichen Dynamik der Bodenfeuchte auf der Feldskala einschließlich Feldexperimenten und hydrologischer Modellierung, (3) der Aufbau verschiedener Modellanwendungen unterschiedlicher Komplexität um die Bodenfeuchtedynamiken und die Abflussentwicklung zu verstehen und die Vorhersage des Abflussvolumens zu verbessern. Um die Zielsetzung 1 zu erreichen, wurden verschiedene Laborversuche durchgeführt. Hierbei wurde der Einfluss der Sondenstabgeometrie und verschiedener Heterogenitäten im Messvolumen bei verschiedenen Feuchtegehalten untersucht. Dies beinhaltete eine detaillierte Analyse wie diese Fehlerquellen die Inversion des Bodenfeuchteprofils beeinflussen. Betreffend der Zielsetzung 2, wurden 2 TDR-Cluster in den Quellgebieten der Wilden Weißeritz installiert (Osterzgebirge) und untersucht, wie gut der Gebietszustand mit räumlich hochaufgelösten Bodenfeuchtedaten der Feldskala charakterisiert werden kann. Um die Interaktion zwischen Evapotranspiration und Bodenfeuchte zu untersuchen wurde das hydrologische Prozessmodell CATFLOW angewendet. Ein Beregnungsversuch wurde durchgeführt um die Zwischenabflussprozesse auf der Hangskala zu verstehen. Die Interaktion zwischen Bodenfeuchte und Abflussentwicklung wurde anhand von drei einander zugeordneten Einzugsgebieten analysiert. Statistische Analysen unter Berücksichtigung von Basisabfluss, Bodenvorfeuchte und verschiedenen Niederschlagscharakteristika wurden verwendet, um auf das Abflussvolumen zu schließen. Auf den verschiedenen Skalen konnte eine hohe Korrelation zwischen der mittleren Bodenfeuchte und dem Abflussbeiwert der Einzelereignisse festgestellt werden. Hierbei konnte die Bodenfeuchte genauso viel Variabilität erklären wie der Basisabfluss. Im Hinblick auf Zielsetzung 3 wurden “Generalised liner models” (GLM) genutzt. Dabei wurden Prädiktorvariablen die den Gebietszustand beschreiben und solche die die Meteorologische Randbedingungen beschreiben genutzt um den Abflussbeiwert zu schätzen. Die Ergebnisse der GLMs wurden mit Simulationsergebnissen des hydrologischen Gebietsmodells WaSiM ETH verglichen. Hierbei haben die GLMs eindeutig bessere Ergebnisse geliefert gegenüber den WaSiM Simulationen. Die GLM Analysen haben aufgezeigt, dass die verwendete Messstrategie mehrerer TDR-Cluster in typischen funktionalen Einheiten eine viel versprechende Methode ist, um den Einfluss der Bodenfeuchte auf die Abflussentwicklung zu verstehen und ein Bindeglied zwischen den Skalen darstellen zu können. Langzeitbeobachtungen solcher Standorte sind in der Lage wichtige Zusatzinformationen bei der Hochwasserwarnung und -vorhersage zu liefern durch die Identifizierung kritischer Gebietszustände für erstere und eine bessere Repräsentation der Vorfeuchte für letztere.

Soil conditions under vegetation cover and their spatial and temporal variations from point to catchment scale are crucial for understanding hydrological processes within the vadose zone, for managing irrigation and consequently maximizing yield by precision farming. Soil moisture and soil roughness are the key parameters that characterize the soil status. In order to monitor their spatial and temporal variability on large scales, remote sensing techniques are required. Therefore the determination of soil parameters under vegetation cover was approached in this thesis by means of (multi-angular) polarimetric SAR acquisitions at a longer wavelength (L-band, lambda=23cm). In this thesis, the penetration capabilities of L-band are combined with newly developed (multi-angular) polarimetric decomposition techniques to separate the different scattering contributions, which are occurring in vegetation and on ground. Subsequently the ground components are inverted to estimate the soil characteristics. The novel (multi-angular) polarimetric decomposition techniques for soil parameter retrieval are physically-based, computationally inexpensive and can be solved analytically without any a priori knowledge. Therefore they can be applied without test site calibration directly to agricultural areas. The developed algorithms are validated with fully polarimetric SAR data acquired by the airborne E-SAR sensor of the German Aerospace Center (DLR) for three different study areas in Germany. The achieved results reveal inversion rates up to 99% for the soil moisture and soil roughness retrieval in agricultural areas. However, in forested areas the inversion rate drops significantly for most of the algorithms, because the inversion in forests is invalid for the applied scattering models at L-band. The validation against simultaneously acquired field measurements indicates an estimation accuracy (root mean square error) of 5-10vol.% for the soil moisture (range of in situ values: 1-46vol.%) and of 0.37-0.45cm for the soil roughness (range of in situ values: 0.5-4.0cm) within the catchment. Hence, a continuous monitoring of soil parameters with the obtained precision, excluding frozen and snow covered conditions, is possible. Especially future, fully polarimetric, space-borne, long wavelength SAR missions can profit distinctively from the developed polarimetric decomposition techniques for separation of ground and volume contributions as well as for soil parameter retrieval on large spatial scales. / Zur Verbesserung der hydrologischen Abflussmodellierung, der Flutvorhersage, der gezielten Bewässerung von landwirtschaftlichen Nutzflächen und zum Schutz vor Ernteausfällen ist die Bestimmung der Bodenfeuchte und der Bodenrauhigkeit von grosser Bedeutung. Aufgrund der hohen zeitlichen sowie räumlichen Dynamik dieser Bodenparameter ist eine flächenhafte Erfassung mit hoher Auflösung und in kurzen zeitlichen Abständen notwendig. In situ Messtechniken stellen eine sehr zeit- und personalaufwändige Alternative dar, deshalb werden innovative Fernerkundungsverfahren mit aktivem Radar erprobt. Diese Aufnahmetechniken sind von Wetter- und Beleuchtungsverhältnissen unabhängig und besitzen zudem die Möglichkeit, abhängig von der Wellenlänge, in Medien einzudringen. Mit dem in dieser Arbeit verwendeten polarimetrischen Radar mit synthetischer Apertur (PolSAR) werden die Veränderungen der Polarisationen ausgewertet, da diese aufgrund der physikalischen Eigenschaften der reflektierenden Medien objektspezifisch verändert und gestreut werden. Es kann dadurch ein Bezug zwischen der empfangenen Radarwelle und den dielektrischen Eigenschaften (Feuchtegehalt) sowie der Oberflächengeometrie (Rauhigkeit) des Bodens hergestellt werden. Da vor allem in den gemässigten Klimazonen die landwirtschaftlichen Nutzflächen die meiste Zeit des Jahres mit Vegetation bestanden sind, wurden in dieser Dissertation Verfahren entwickelt, um die Bodenfeuchte und die Bodenrauhigkeit unter der Vegetation erfassen zu können. Um die einzelnen Rückstreubeiträge der Vegetation und des Bodens voneinander zu trennen, wurde die Eindringfähigkeit von längeren Wellenlängen (L-band, lambda=23cm) mit neu entwickelten (multi-angularen) polarimetrischen Dekompositionstechniken kombiniert, um die Komponente des Bodens zu extrahieren und auszuwerten. Für die Auswertung wurden polarimetrische Streumodelle benutzt, um die Bodenkomponente zu modellieren und dann mit der extrahierten Bodenkomponente der aufgenommenen Daten zu vergleichen. Die beste Übereinstimmung von Modell und Daten wurde als die gegebene Bodencharakteristik gewertet und dementsprechend invertiert. Die neu entwickelten, polarimetrischen Dekompositionstechniken für langwelliges polarimetrisches SAR basieren auf physikalischen Prinzipien, benötigen wenig Rechenzeit, erfordern keine Kalibrierung und sind ohne Verwendung von a priori Wissen analytisch lösbar. Um die entwickelten Algorithmen zu testen, wurden in drei verschiedenen Untersuchungsgebieten in Deutschland mit dem flugzeuggetragenen E-SAR Sensor des Deutschen Zentrums für Luft- und Raumfahrt (DLR) polarimetrische SAR Daten aufgenommen. Die Auswertungen der PolSAR Daten haben bestätigt, dass die besten Invertierungsergebnisse mit langen Wellenlängen erzielt werden können (L-Band). Des Weiteren konnten bei der Bestimmung der Bodenfeuchte und der Bodenrauhigkeit hohe Inversionsraten erreicht werden (bis zu 99% der Untersuchungsfläche). Es hat sich gezeigt, dass die polarimetrischen Streumodelle bei der gegebenen Wellenlänge nicht für bewaldete Gebiete geeignet sind, was die Anwendbarkeit des Verfahrens auf landwirtschaftliche Nutzflächen einschränkt. Die Validierung mit Bodenmessungen in den Untersuchungsgebieten, die zeitgleich zu den PolSAR Aufnahmen durchgeführt wurden, hat ergeben, dass eine kontinuierliche Beobachtung des Bodenzustandes (ausgenommen in Zeiten mit gefrorenem oder Schnee bedecktem Boden) mit einer Genauigkeit (Wurzel des mittleren quadratischen Fehlers) von 5-10vol.% für die Bodenfeuchte (in situ Messbereich: 1-46vol.%) und von 0.37-0.45cm für die Bodenrauhigkeit (in situ Messbereich: 0.5-4.0cm) möglich ist. Besonders künftige Fernerkundungsmissionen mit langwelligem, voll polarimetrischem SAR können von den entwickelten Dekompositionstechniken profitieren, um die Vegetationskomponente von der Bodenkomponente zu trennen und die Charakteristik des Oberbodens flächenhaft zu bestimmen.

The temporal dynamics of hydrological model performance gives insights into errors that cannot be obtained from global performance measures assigning a single number to the fit of a simulated time series to an observed reference series. These errors can include errors in data, model parameters, or model structure. Dealing with a set of performance measures evaluated at a high temporal resolution implies analyzing and interpreting a high dimensional data set. This paper presents a method for such a hydrological model performance assessment with a high temporal resolution and illustrates its application for two very different rainfall-runoff modeling case studies. The first is the Wilde Weisseritz case study, a headwater catchment in the eastern Ore Mountains, simulated with the conceptual model WaSiM-ETH. The second is the Malalcahuello case study, a headwater catchment in the Chilean Andes, simulated with the physicsbased model Catflow. The proposed time-resolved performance assessment starts with the computation of a large set of classically used performance measures for a moving window. The key of the developed approach is a data-reduction method based on self-organizing maps (SOMs) and cluster analysis to classify the high-dimensional performance matrix. Synthetic peak errors are used to interpret the resulting error classes. The final outcome of the proposed method is a time series of the occurrence of dominant error types. For the two case studies analyzed here, 6 such error types have been identified. They show clear temporal patterns, which can lead to the identification of model structural errors.

Biobased materials made from renewable resources, such as wood, play an important role in the sustainable development of society. One main challenge of biobased building materials is their inherent moisture sensitivity, a major cause for fungal decay, mold growth and dimensional instability, resulting in decreased service life as well as costly maintenance. A new building material known as wood-plastic composites (WPCs) has emerged. WPCs are a combination of a thermoplastic matrix and a wood component, the former is usually recycled polyethylene or polypropylene, and the latter a wood processing residual, e.g. sawdust and wood shavings. The objective of this thesis was to gain more insight about characteristics of WPCs containing a modified wood component. The hypothesis was that a modified wood component in WPCs would increase the moisture resistance and durability in outdoor applications. The study comprises both injection molded and extruded WPC samples made with an unmodified, acetylated, thermally modified or furfurylated wood component in a polypropylene (PP), high density polyethylene (HDPE), cellulose ester (CAP, a cellulose ester containing both acetate and propionate substituents) or polylactate (PLA) matrix. The WPCs were prepared with 50-70 weight-% wood. The emphasis was on studying the moisture sorption, fungal resistance and micromorphological features of these new types of composites. Water sorption in both liquid and vapor phases was studied, and the biological performance was studied both in laboratory and in long term outdoor field tests. Micromorphological features were assessed by analyzing of the wood component prior to and after processing, and by studying the composite microstructure by means of a new sample preparation technique based on UV excimer laser ablation combined with scanning electron microscopy (SEM). Results showed that the WPCs with a modified wood component had a distinctly lower hygroscopicity than the WPCs with unmodified wood, which resulted in less wood-plastic interfacial cracks when subjected to a moisture soaking-drying cycle. Durability assessments in field and marine tests showed that WPCs with PP or CAP as a matrix and 70 weight-% unmodified wood degraded severely within a few years, whereas the corresponding WPCs with a modified wood component were sound after 7 years in field tests and 6 years in marine tests. Accelerated durability tests of WPCs with PLA as a matrix showed only low mass losses due to decay. However, strength losses due to moisture sorption suggest that the compatibility between the PLA and the different wood components must be improved. The micromorphological studies showed that WPC processing distinctly reduces the size and changes the shape of the wood component. The change was most pronounced in the thermally modified wood component which became significantly reduced in size. The disintegration of the modified wood components during processing also creates a more homogeneous micromorphology of the WPCs, which may be beneficial from a mechanical performance perspective. Future studies are suggested to include analyses of the surface composition, the surface energy and the surface energy heterogeneity of both wood and polymer components in order to tailor new compatible wood-polymer combinations in WPCs and biocomposites. / <p>QC 20121119</p>