Historic buildings and monuments are a precious finite asset and powerful reminders for future generations of the work and way of life of earlier cultures and civilisations. The stone cleaning and restoration of historic buildings is a crucial element in keeping the good look, integrity and quality of the fine art, method of construction and architecture of previous civilisations. Stone cleaning is one of the most noticeable changes a building can be subjected to, which changes its appearance, persona and environmental context. In this study, a series of physical and chemical tests were conducted to further investigate, evaluate and improve the efficiency of building cleaning. Seven different abrasives were adopted for air abrasive cleaning, including copper slag (fine, medium and coarse), recycled glass (fine, medium and coarse) and hazelnut/almond shell (natural abrasive), on a total of eight masonry stones and clay bricks, including yellow sandstone, red sandstone, limestone, marble, granite, white clay brick, yellow clay brick and red clay brick. Physical investigations included sieve tests and impact tests on the abrasives, greyscale image analysis, thickness reduction measurements, Vickers surface hardness tests, Charpy impact tests and water absorption tests. Chemical investigations included Scanning Electron Microscope (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDX) analyses. Sieve tests and impact tests confirmed that the abrasives utilised were fairly reliable, and the abrasives with high bulk densities were stronger and tougher than those with low bulk density. Greyscale digital image analysis indicated a lower greyscale value corresponded to a dirtier masonry surface. In general, the greyscale continuously increased with the increasing cleaning time and tended to be stable when the surface became fully cleaned. The cleanness was also introduced for assessing the effectiveness of the building cleaning. Similar trends could be observed. Both parameters proved to be significantly useful. For most of the samples, monotonic increase trends were observed between the greyscale and thickness reduction. The image analysis on greyscale and the thickness measurement were two useful methods for assessing the cleaning degree of a masonry stone or clay brick. Based on the analysis on all the testing data, it is possible to recommend a more suitable abrasive for each masonry stone or brick. For granite and red clay brick, medium glass produced the best performance, while for limestone, marble and red sandstone, fine glass was promising. For yellow clay brick, fine slag could be the best option, while for yellow sandstone the natural abrasive was found to be the most suitable. vi The Vickers hardness test results indicated that a larger hardness corresponded to a harder masonry surface. Also the surface hardness continuously increased with the increasing cleaning time but at a decrease rate. Most of the increasing trends of the surface hardness could be approximately expressed using parabolic relationships. Granite was found to be the hardest, and followed by marble and limestone. However, there were no big differences in the surface hardness between yellow clay brick, yellow sandstone, red sandstone and white clay brick. The impact resistances of seven masonry stones and bricks were obtained by conducting the Charpy impact resistance tests. Granite showed the highest impact resistance among all the stones and bricks and was followed by marble, limestone, clay bricks and sandstones. The stones and bricks with higher impact resistances also had higher hardness values but lower water absorptions. The water absorbing capacity of the seven masonry stones and bricks was quantitatively determined. Two types of clay bricks showed the highest water absorptions, and the water absorptions for limestone, yellow sandstone and red sandstone were also quite high. However, the water absorption of marble and granite was found to be very low. Larger water absorption corresponded to a softer stone or brick, while smaller water absorption corresponded to a harder stone or brick. The chemical investigations by using the SEM and EDX techniques showed that the chemical substances on the masonry surface varied largely for different types of stones and bricks. This study showed the way to detect such soiling using chemical analysis by monitor the changes in chemical elements and compounds during the building cleaning. Finally, comprehensive conclusions were presented, together with useful suggestions for future work.

The recycling of demolished masonry rubble as the coarse aggregate in new concrete represents an interesting possibility at a time when the cost of dumping such material is on the increase. With growing concerns over the environmental impact of aggregate extraction and the continued rise in aggregate demand in the UK, it is clear that the market is now there for recycled and secondary aggregates. The present investigation consists of experimental and theoretical studies into the effects of using recycled aggregates to produce concrete instead of virgin aggregates. The aggregates used have been recycled from construction and demolition waste. The recycled aggregates were predominately made up of crushed bricks but the aggregates did contain impurities such as timber and mortar. New bricks were crushed to form an aggregate in order to investigate the properties of brick as a material without impurities. The physical properties of the various aggregates were firstly examined and compared with granite aggregate, an aggregate proven in the production of good quality concrete. Concrete was then produced with the aggregates and all the physical and mechanical properties of the concretes were examined in some detail. The results showed that recycled masonry aggregates can be used successfully to produce· concrete of an acceptable standard. New test methods were presented in this investigation to determine brick porosity and water absorption. This involved the testing of broken brick fragments under vacuum, rather than the testing of whole brick units by 5hrs boiling or 24hrs submersion in cold water. The new test methods proved to be easy to perform and provided accurate results. A new test method for estimating the strength of bricks was presented. This involved point-loading of masonry specimens to obtain strength index values. From the pointload results, equations were presented relating the strength index values of brick fragments to the compressive strength of whole brick units. This involved the development of shape factors for different masonry specimens. The point-load test is easy to perform, presents a cheaper alternative to heavy compression machines and can be used on site to determine the suitability of recycled bricks as the aggregate in new concrete.

The need for improved timber grading is key to improving Scottish forestry: the majority (80%) of the sustainable softwood population in Scotland is Sitka spruce of variable quality. Current visual assessment of strength and stiffness is inaccurate, and machine stress grading in sawmills is little better due to incorrect assumptions regarding consistency within softwood species and between trees of the same stand. The author develops and evaluates non-destructive test (NOT) methods for Scottish Sitka spruce based upon impact-e9ho testing across a range of scales from plank, to log, to standing tree. Correlations between harmonic wave propagation velocity and elastic modulus of 0.62 ::; R2 ::; 0.71 were possible in Sitka spruce under a range of conditions including: genotype progeny, variable height and radial position in stem, and variable knot content. In achieving this correlation, the research also investigated acoustic parameters such as: time of flight velocity, damping ratio, and resonant peak behaviour with regard to their influence on dynamically derived moduli of elasticity. Examination of variation in wood properties (including static elastic modulus, knot content, simulated decay, density, and grain alignment) on these acoustic parameters was conducted on semi-controlled specimens of differing homogeneities. The consequences of these results should influence the development of timber NOT tools. In addition to the development of an NOT method, the author has provided the first large-scale derivation of reference values for dynamic stiffness and other acoustic properties for 35 year old logs and beams of Sitka spruce in Scotland.

Water ingress, usually by wind-driven rain, is the main cause of premature deterioration in masonry structures. Water acts as a transport mechanism for aggressive chemicals and can also undergo freeze/thaw cycles leading to bursting of the masonry microstructure. Factors such as the absorption rates of brick, water/cement ratio of the mortar, workmanship of the mason and poor design detail have all been identified as influencing the amount of water likely to penetrate a structure. It is also recognized that the majority of water ingress occurs at the brick unit/mortar joint interface, where interstices are present that allow access to the masonry interior. The size, extent and influence that the brick/mortar interface has in governing water ingress is likely to be controlled by both the applied stress level and bed orientation of the main mortar beds relative to the direction of loading. Very little research has investigated these parameters in detail. By using a new ingress measurement technique, the effect of the applied stress level and bed orientation was quantified. The main mortar beds of concentrically loaded masonry panels were found to deteriorate in their resistance to water ingress as they were orientated from perpendicular to parallel relative to the direction of loading. Poisson's ratio effects, which generated differential expansion between brick and mortar were believed to control water ingress at mortarjoints orthogonal to the main beds. Water ingress at these mortarjoints was also found greatly influenced by both applied stress level and bed orientation. Factors such as the applied pressure head of water impinging onto the panel, the variability of the brick type used, eccentricity of applied loads and the pre-wetting of panels were also found to have some controlling influence on the water ingress characteristics of masonry. Empirical modelling of water ingress dependent upon time, stress level, bed orientation and pressure head of water, was also undertaken. This enabled the volume of water ingress to be mathematically generated, with these models exhibiting good agreement with experimental data. Suggestions for future work include assessing the effect of higher applied stress levels on water ingress, verification of the laboratory work with on-site tests and the introduction of freeze/thaw testing on loaded panels to simulate an abrasive external environment. Numerical analysis using finite element modelling was also identified.

Direct electric curing is the method by which the hydration reactions within concrete are thermally accelerated by passing an alternating electric current through the sample. This use of electricity as a means of supplying heat to young concrete and mortar has become recognised as a more effective and energy efficient form of accelerating the curing process than traditional steam curing. The present investigation involves studying the affects of thermally accelerated curing of cementitious materials in comparison to normally non-heated curing. Prior to mixing, tests are performed on the constituents of the cementitious mixes. Results of these tests are used in the creation of mix designs for mortar and concrete samples. A range of concrete mixes are designed with and without additives and admixtures are used to make cubes, slabs and beams. From the testing results, the factors affecting the short and long term properties of electrically cured cementitious materials are investigated and heating regimes are presented to achieve specific properties of both strength and durability at specific ages. A substantial section of reinforced concrete is required to gain representative results in electrically curing reinforced concrete slabs. Compressive strength is difficult to measure due to the electrical distortion affects of inserts and the damage caused by coring so that at present, basic maturity concepts are used as a compressive strength guide which limits the validity of results obtained. This research looks at refining these concepts to include early age heating effects induced by direct electric curing. The microstructural development of concrete when subjected to accelerated curing is also considered. The affect of delay periods and maximum temperature is studied using a scanning electron microscope and the results presented.

No description available.

The secondary energy use and GHG emissions have noticeably increased during recent decades in Canada; the residential sector accounted for the third largest portion of total energy use. The government and market turned to building highly efficient residential buildings for energy savings. However, premature technologies and designs brought countless issues from conception to operation stages resulting in performance discrepancies between the modelled results and field performance. This thesis looked into ten LEED Gold certified social houses in Victoria and Vancouver, BC to reveal their performance gaps, to investigate possible causes, to seek practical solutions and to summarize proper recommendations for the green building industry. It was accomplished by collecting LEED energy model and utility data for two years of each building, comparing their predicted and actual energy consumption, examining each site, discussing with facility managers and analyzing performance gaps. In addition, occupancy and building staff surveys served as robust support to the research. The assessment shows only two buildings realized their preliminary high-performance goals. Other buildings sustained an offset of energy consumption from the minimum of 22.1\% to the maximum of 281.7\% compared to their proposed models. The reasons for the discrepancy covered all the phases of a building’s life from design to construction, to commissioning and to post-occupancy. The most common concerns were the unexpected inefficiency of air source heat pumps and unpredictable occupancy behaviours such as leaving windows open in winter. In consideration of these, the calibration of energy models according to refined performance curves of heat pumps and particular inputs for social housings would provide a more accurate prediction. Together with improved designs, adequate commissioning and appropriate operation, performance gaps can be narrowed to a greater extent. / Graduate

The concrete impact on the environment is mainly on cement production, which accounts for 7 percent of total global carbon dioxide emissions. The amount of Carbon dioxide emissions is estimated to 700-800 kilo of carbon dioxide per 1000 kilo of cement produced. About 60 percent of emissions comes from the calcination of limestone, and the remaining 40 percent comes from the burning of fossil fuels due to the heat that must be added during the calcination [2]. Every year it produced around 2 million tonnes of cement in Sweden, which in turn results in the emission of approximately 1.5 million tonnes of carbon dioxide [5]. A suitable solution has been found in the use of supplementary cementitious materials, also known as mineral admixtures[3]. These materials can be used to replace cement in concrete  as they possess pozzolanic and cementitious properties. The most common industrial by-products used in Sweden at the moment are fly ash and granulated blast furnace slag. To find out how big of an amounts of carbon dioxide emission can be reduced by replacing the parts of the cement with by-products, you have to conciderate the whole concrete life cycle beacuse concrete also ties up carbon dioxide. When carbon dioxide  comes in contact with water in the pore solution of the concrete  bicarbonate plus a hydrogen ion is formed. Bicarbonate  is then dissolved to form carbonate  plus a hydrogen ion. When carbonate  comes in contact with calcium, calcium carbonate is formed. This process is called carbonation and continues throughout the life of the concrete. Calcium hydroxide has a very low solubility compared to other hydroxides and will be the first to dissolve and release calcium ions in the pore solution. Calcium silicate stabilized by high pH - value and Ca ions in the pore solution. Calcium Hydroxides releaseing of  lowers the pH content in the pore solution which results in calcium silicate hydrate also begins to dissolve and release ions. However, changing the release of structural reconstruction of Calcium Silicate Hydrate results in a lower Ca / Si - ratio. When this ratio falls to less than 1 and the pH of the pore solution is around 10,  silica gel is formed. Mineral admixtures in form of bee products such as fly ash and granulated blast furnace slag will reduce the amount of calcium hydrate in the cement paste and increase the amount of calcium silicate hydrate. Simplification of Fick's second law developed by the CBI has been used in numerical calculations for the concrete's carbon uptake over time. 3 different types of cement, Portland cement, fly ash cement and slag cement has been set against each other from a carbon dioxide perspective.Portland cement: 1 m^3 concrete of type CEM I with strength C30/37 contribute with 263 kg of carbon emissions during production. Over time, this 1 m^3 of concrete have tied up a total of 134 kg of carbon dioxide through carbonation. The total carbon emissions for 1 m^3 concrete of type CEM I with strength C30/37 remains 129 kg. Flygaskecement: 1 m^3 concrete of type CEM II / B-V (35% F) with strength C30/37 is contributing with a total of 75 kg of carbon dioxide emissions. Slag Cement: 1 m^3 concrete of type CEM II / B-S (35% F) with strength C30/37 is contributing with a total of 41 kg of carbon dioxide emissions.

No description available.

The design of a structure should be regarded as the design of a system. In this licentiate thesis a method (concurrent engineering) for the design of systems is studied parallel with the development of the system itself. The purpose of the work is twofold: To study the application of concurrent engineering (CE) as a method to manage the design work for the design of a glulam truss. To develop a glulam truss and investigate if it can be made competitive on the Swedish market. The qualitative study started with the formation of a CE team consisting of an architect, a contractor and a manufacturer of glulam with the researcher as the project manager. The idea in CE is to let members from different parts of the design work (design, production and manufacturing) solve the problem together. Through the concurrent work of these members a proposal of a glulam truss was posed. The proposal was then verified and refined by the CE team through several iterations between resistance considerations and production issues. The qualitative study showed that the members of the CE team are equally important for the success of the development project. The project manager needs to be independent and have a wide knowledge base. Furthermore, the production issues were investigated early in the design process, which is an advantage for the manufacturer of the truss. The quantitative study focused heavily on the solution for the joint in the glulam truss. A connection type new to the Swedish market was proposed; nails with slotted-in steel plates. The joint consists of steel plates placed in internal slots in the glulam member which is assembled by shooting the nails through the glulam and the steel plates with a nailer. Medium-sized joints were tested in tension parallel to the grain and the resistance was found to be on average 8.35 kN/nail and two steel plates. Production considerations for the joint type revealed that sawing the slots to accommodate the steel plates could be a problem and this was further investigated in laboratory tests on full-scale joints. The full-scale tests were performed using the theory of statistical experimental design aiming to show tendencies in the behaviour rather than performing a parameter study. The specimens were designed without eccentricities in the joint. The results showed that buckling tendencies of the steel plates must be suppressed and therefore the design of the full-scale joint was adjusted to counteract this. Tension perpendicular to the grain in the joint was qualitatively studied. The results showed that the occurrence of a compressive force close to the tensile force does not affect the resistance in tension perpendicular to the grain for this joint design and this failure mode will not set any demands on the resistance of the truss. The glulam truss was optimised with respect to material cost to investigate the competitiveness on the Swedish market. First order theory was used assuming linearly elastic material behaviour. The rotational capacity of the joints was included in the analysis. Together with estimates for the production cost of a joint, the results showed that a glulam truss using this connection type would have a production cost of approximately 19,200 SEK/truss. The competitiveness of this cost must be judged by the market, but steel trusses have a production cost of about 15,600 SEK/truss while other glulam structural elements range from 18,300-31,000 SEK/element. / <p>Godkänd; 2001; 20070316 (ysko)</p>