Minerals can be incorporated in concrete to promote self-healing. Encapsulation of minerals is needed for avoiding undesired reactions before concrete cracks. Therefore, this study designed a novel ...capsule. The core materials of the capsules were either cement or a combination of cement and superabsorbent polymers (SAPs), which were granulated by poly (ethylene glycol) followed by a waterproof layer (i.e., epoxy resin and sand). The structure and hydration process of capsules, self-healing efficiency of cracked mortars and healing product were characterized. Results showed that core materials in capsules could react with water with dissolution of PEG and swelling of SAP swelled in cracks. Moreover, specimens incorporated capsules showed high sealing ratio for cracks below 400 μm and even inside cracks wider than 200 μm could be bridged due to capsules with SAP. Recovery of water tightness, flexural and compressive strength were obtained. The healing products were C-S-H and CaCO3.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Detailed knowledge on expected infiltration percentages through various exterior cladding surfaces is of importance when conducting hygrothermal simulations to evaluate the long-term performance of ...wall assemblies. Due to the stochastic nature of rainwater infiltration through wall assemblies, it is not possible to precisely predict the amount of rainwater that will infiltrate. However, laboratory and field tests may provide insight into the range of infiltration rates that can be expected for a given cladding and insight into the impact of deficiencies and the parameters affecting infiltration. Therefore, quantitative studies concerning infiltration rates, which were mostly laboratory studies, were reviewed. Based on the reviewed studies, the driving forces for infiltration were determined and the impact of the applied test method, pressure difference and water deposition rate on the infiltration rates was analysed. A methodology to obtain information on infiltration percentages without performing additional laboratory tests was proposed and a categorization of cladding materials was developed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract
Windows are important in buildings intended for human activities as they let in daylight and provide views. However, they may also be vulnerable in terms of heat loss, air leaks, rain ...tightness, and durability. In Nordic climates featuring severe driving rain exposure, water tightness is of outmost importance. SINTEF has for many decades been testing windows as part of the Norwegian yearly product control. Air permeability and water tightness are tested according to NS-EN 1026 and NS-EN 1027, respectively. The windows are then classified as described in NS-EN 12207 and NS-EN 12208. This paper summarises experiences from the last two decades of testing, presenting the results of 1130 tests of windows’ air permeability and rain tightness. The overall trend is that air and rain tightness performance of the windows have improved over time. Certain hinge configurations are clearly better than others, with tilt and turn windows performing the best and top hung casement windows the poorest. There is a clear trend that highly rainproof windows also exhibit lower air permeability. Multiple-window screens fail the test more often since they feature longer perimeters of opening. The contribution of weather sweep seals to the water tightness is significant as it makes an extra rain barrier to the joint between casement and frame. In general, leakage between the frames of double windows and in the joints of the frame occurs at lower air pressures than leakages between casement and frame. The lessons learned from the survey may guide future development of weatherproof windows.
We introduce Coverage Axis++, a novel and efficient approach to 3D shape skeletonization. The current state‐of‐the‐art approaches for this task often rely on the watertightness of the input LWS*15; ...PWG*19; PWG*19 or suffer from substantial computational costs DLX*22; CD23, thereby limiting their practicality. To address this challenge, Coverage Axis++ proposes a heuristic algorithm to select skeletal points, offering a high‐accuracy approximation of the Medial Axis Transform (MAT) while significantly mitigating computational intensity for various shape representations. We introduce a simple yet effective strategy that considers shape coverage, uniformity, and centrality to derive skeletal points. The selection procedure enforces consistency with the shape structure while favoring the dominant medial balls, which thus introduces a compact underlying shape representation in terms of MAT. As a result, Coverage Axis++ allows for skeletonization for various shape representations (e.g., water‐tight meshes, triangle soups, point clouds), specification of the number of skeletal points, few hyperparameters, and highly efficient computation with improved reconstruction accuracy. Extensive experiments across a wide range of 3D shapes validate the efficiency and effectiveness of Coverage Axis++. Our codes are available at https://github.com/Frank-ZY-Dou/Coverage_Axis.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
•Rice husk is thermally treated into different forms of ash (RHA) and biochar (RHB).•RHA from uncontrolled burning shows features of a controlled low strength material.•Addition of RHB significantly ...improves strength due to internal curing effect.•Combination of RHA and RHB eliminates autogenous shrinkage for a reasonable period.•Processed industrial grade RHA shows a better overall performance than other forms.
Rice husk ash, an industrial by-product from boilers for energy generation and furnace for parboiling rice, has been explored as admixture to replace part of cement in structural mortar. However, due to uncontrolled burning process, the produced rice husk ash (iRHA) has low amorphous silica and contain unburnt husk particles, which affects durability of mortar containing iRHA. This study investigates thermal treatment of iRHA (TRHA) to produce ash with improved physical and chemical properties, which can then be used to reduce cement content in mortar by 20% (by weight). Furthermore, combination of rice husk biochar (RHB) and iRHA, where RHB is used to replace 10% and 40% by weight of iRHA, is used to improve mechanical and durability properties of iRHA-RHB mortar. The performance was compared with control (without RHA) and mortar containing RHA produced under controlled laboratory condition (LabRHA). Experimental results showed that addition of TRHA increased the strength of mortar by 20% and 34% at early stage (after 7 days) and matured age (after 120 days) compared to mortar with iRHA respectively. Although strength development was similar to control, TRHA-mortar showed lower autogenous shrinkage and water permeability, indicative of its improved durability as building material. Addition of RHB, as 40% replacement of iRHA, offers improvement in long-term (120-day) compressive strength and water tightness by 17% and 23% respectively compared to iRHA; it also has 12% more water-tightness than the control. Strength afforded by the carbon content of RHB particles and its reservoir effect eliminated autogenous shrinkage over the 6-week monitoring period. Among the tested admixtures, LabRHA offered maximum improvement in water-tightness, leading to 23% lower capillary absorption compared to control. Findings from this study suggest that thermal treatment and application of RHB can valorise industrial grade RHA as admixture in cementitious building materials, which will also reduce the need for landfilling and sequester carbon in the built environment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Flood water can affect vehicles significantly, which in turn can increase the negative effects of floods as vehicles are washed away by the flow and become a form of debris. In cities, most ...fatalities during floods occur inside vehicles. Consequently, it is necessary to establish thresholds for vehicle stability during this type of event to provide information necessary for flood risk management. This article analyses the available stability models developed over recent years to determine such thresholds. The stability models were grouped according to the way in which they approached car watertightness and the stability thresholds proposed by each of them were compared. It was found that these thresholds vary over a relatively wide range. Additionally, the experimental data were compared with the results provided by these studies leading to the conclusion that several of the stability models analysed do not fit measured data well. New research is required to overcome the simplifications made by the state‐of‐the‐art models and to try to standardise the decision criteria which should be adopted to define stability thresholds for vehicles of different characteristics.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
This paper presents an approach for isogeometric analysis of 3D objects using rational Bézier tetrahedral elements. In this approach, both the geometry and the physical field are represented by ...trivariate splines in Bernstein Bézier form over the tetrahedrangulation of a 3D geometry. Given a NURBS represented geometry, either untrimmed or trimmed, we first convert it to a watertight geometry represented by rational triangular Bézier splines (rTBS). For trimmed geometries, a compatible subdivision scheme is developed to guarantee the watertightness. The rTBS geometry preserves exactly the original NURBS surfaces except for an interface layer between trimmed surfaces where controlled approximation occurs. From the watertight rTBS geometry, a Bézier tetrahedral partition is generated automatically. By imposing continuity constraints on Bézier ordinates of the elements, we obtain a set of global Cr smooth basis functions and use it as the basis for analysis. Numerical examples demonstrate that our method achieves optimal convergence in Cr spaces and can handle complicated geometries.
•Use Cr rational trivariate Bézier–Bernstein polynomials as basis in isogeometric analysis.•Convert NURBS models into watertight geometry represented by rational triangular Bézier splines (rTBS). A compatible subdivision scheme is developed to guarantee the watertightness of trimmed NURBS models.•Bézier tetrahedral partition from the watertight rTBS geometry automatically.•Construct Cr smooth basis functions by imposing continuity constraints on Bézier ordinates of the elements.•Demonstrate optimal convergence rates in Cr space using a smooth-refine-smooth scheme.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Abstract
The joints around heavy terrace doors are considered a weak point in rain-exposed façades, as it is vulnerable to defects in design and construction. The insertion process of heavy sliding ...doors is a notable challenge. Design recommendations from manufacturers as well as national advisory agencies are currently lacking. This paper presents a full-scale laboratory study on the water tightness of heavy sliding doors with joints waterproofed according to five different solutions. The door assembly is mounted in a pressurized cabinet with water spray nozzles to simulate wind-driven rain. The interior side of the joint around the door is monitored for moisture leaks at steadily increasing pressure levels. It was found that leaks most often occur in the corners of the frame. Sealant mounted before the door itself was hoisted in place tended to be twisted or distorted as the door was adjusted in the frame, spoiling the waterproofing. A common feature of the most watertight solutions was that the sealant was mounted after the door itself was fastened to the frame. The sealant should be continuous, flexible, mounted in a single plane, and preferably be accessible during the assembly process. Waterproofing recommendations for the design and insertion of sliding doors should account for practical challenges brought on by the heavy weight.
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