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1.	Al-Gburi, Majid, et al. (author) Reducing Thermal Crack Risks Caused by Restraint in Young Concrete - A Case Study on Walls of Water Tanks 2022 In: Nordic Concrete Research. - : Walter de Gruyter. - 0800-6377 .- 2545-2819. ; 66:1, s. 41-54 Journal article (peer-reviewed)abstract Concrete cracks in structures such as water tanks and nuclear power stations cause anxiety to owners, contractors and engineers. These cracks may significantly increase the structure’s permeability and thus increase leakage, reduce durability, and eventually lead to loss of structural functionality. Therefore it is important to minimize their occurrence and size. To identify effective ways of minimizing cracking in young concrete segments, a parametric study was conducted using the finite element method (FEM). Parameters considered include casting sequence, joint position, wall height, and cooling. The study examined continuous and jumped casting approaches to the casting of a cylindrical reinforced concrete tank for a sewage-treatment plant, with and without the application of the ‘kicker’ technique in which the lower part of the wall is cast with the slab. The main cause of cracking is thermal change and restraint imposed by adjacent older structures, and the FEM predictions agree well with experimental observations. Continuous casting is most effective at minimizing cracking because it creates only two contact edges between newly cast and existing structures producing the lowest level of restraint. The kicker technique is shown to be very effective for reducing restraint and consider rephasing.
2.	Andersson, Louise, et al. (author) Continuous Preventive Bridge Maintenance of Swedish Municipalities : A Survey on Common Practice 2018 In: Nordic Concrete Research. - Oslo : Walter de Gruyter GmbH. - 2545-2819 .- 0800-6377. ; 58 Journal article (peer-reviewed)abstract As part of a report [1] on continuous preventive bridge maintenance, a survey was conducted with Swedish municipalities. The survey’s focus was on bridges and preventive maintenance, as well as the demands and performance control stated by the municipalities. The preventive maintenance the survey focused on was the annual maintenance concerning washing, cleaning of drainage system and removal of vegetation. The survey showed both similarities and differences within the municipalities but also in comparison with Swedish Transport Agency (STA).
3.	Andersson, Louise, et al. (author) Effect of High-Pressure Washing on Chloride Ingress in Concrete : Development of an Accelerated Test Method 2022 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 67:2, s. 35-50 Journal article (peer-reviewed)abstract Bridges constitute an important part of the infrastructure. For bridges to have the longest possible service life with minimum repairs, the maintenance is of great importance. One type of bridge maintenance that is rarely researched is the continuous preventive maintenance. The continuous preventive maintenance consists of removal of vegetation, cleaning of bridge joints and drainage systems as well as high-pressure washing of the structure. The effect of washing is discussed but not properly researched. A study on the effectiveness of high-pressure washing on concrete is therefore being conducted. An accelerated test method is being developed to mimic field testing. The method has been developed through tests on small concrete specimens subjected to fluctuating temperature, fluctuating moisture, and repeatable exposure to de-icing salt during several cycles. The specimens are of two recipes where one represents an old concrete bridge with rather high water-cement ratio (0.6) and the other one represents a new concrete bridge with a low water-cement ratio (0.4). The first two versions of the method are described. The second version shows promising results, but the method needs further development to incorporate additional factors.
4.	Baba Ahmadi, Arezou, 1985, et al. (author) Utilization of Bio Ashes in Cement-based Materials: A Case Study in Cooperation with Pulp and Paper and Energy Production Industries in Sweden 2020 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 63:2, s. 63-78 Journal article (peer-reviewed)abstract Worldwide increased concern of the CO2 emissions has led to the replacement of coal by biomass in combustion-based power plants. However, this would cause the scarcity of fly ash, one of the most well-known rest products from coal combustion, which is used as supplementary cementitious materials (SCM) in construction sector to reduce the large environmental footprint of cement production. Seeking to find alternative SCMs, this article aims to demonstrate the viability of using bio ashes in Sweden as SCM, which, due to lack of studies validating their value, are landfilled today. According to the obtained results, bio ashes produced at pulp and paper industries have a considerably consistent chemical composition and exhibit a satisfactory pozzolanic behaviour. Nevertheless, according to the conclusions of this study, the pozzolanicity of these alternative binders is not reflected equally with respect to the most known reactivity tests for common SCMs. The results imply that although “R3” tests method infers the pozzolanic characteristics of the bio ashes in focus of this study, the “activity index test” as well as “calcium consumption test” indicate otherwise.
5.	Brodd, Elin, et al. (author) The Use of Slag in Accelerated Shotcrete for Rock Support : A Pilot Study on the Influence on the Early Compressive Strength 2023 In: Nordic Concrete Research. - : Walter de Gruyter. - 2545-2819. ; 69:2, s. 73-86 Journal article (peer-reviewed)abstract Today, the world is facing an enormous challenge where the emissions of greenhouse gases mustbe reduced significantly to stop the increasing mean temperature. For the construction industry,this challenge means that structures must be designed more carefully, and materials must be usedand produced more efficiently. Concrete is one of the most widely used materials, and cementproduction alone contributes to around 8 % of the world's total CO2 emissions. This paper presentsa pilot study in which part of the cement clinker content in accelerated shotcrete is replaced withground granulated blast furnace slag (GGBS). Shotcrete is widely used as part of the rock supportfor tunnels in hard rock and has a large cement content. Thus, the environmental impact must bereduced significantly to meet future demands. However, introducing GGBS will slow downstrength development, which is a crucial part of shotcrete. Thus, this paper aims to investigate theearly strength development, i.e., after one and seven days. The results show that an averagecompressive strength of 18 MPa can be reached after 24 hours when 35 % of the cement clinkercontent is replaced with GGBS. Finally, some important topics for further studies are pointed out.
6.	Cyron, Wojciech, et al. (author) Bonded Concrete Overlays: A Brief Discussion on Restrained Shrinkage Deformations and Their Prediction Models 2019 In: Nordic Concrete Research. - : Walter de Gruyter. - 0800-6377 .- 2545-2819. ; 61:2, s. 107-129 Journal article (peer-reviewed)abstract Bonded concrete overlays (BCO) on bridge decks are beneficial solutions due to their superior properties as compared to the typical asphalt pavement. A significant number of overlays suffer however, from occurrence of cracks and delamination due to poor bond, and restrained shrinkage and thermal dilation. Over the past years different appraisals for estimation of the restrained deformations have been developed, from micro-scale models, based on poromechanics, to empirical equations as given in B3 or B4 models suggested by Baiant. This paper provides a short overview of calculation models along with a brief theoretical explanation of shrinkage mechanism.
7.	During, Otto, et al. (author) Rice Husk Resource for Energy and Cementitious Products with Low CO2 contributions 2018 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 59:2, s. 45-58 Journal article (other academic/artistic)abstract Rice Husk Ash (RHA) is a well-known supplementary cementitious materials (SCMs) that can be used for concrete with reduced CO2 contributions. In 2016, only Nepal produced 5.2 million tonnes rice that gave about 1.14 million tonnes rice husk. The rice husk can also be used directly in a cement kiln as a fuel. This study analysis the potential CO2 reductions from three scenarios and emphasis strengths, weaknesses, opportunities and treats in the production systems for initiate a decision process with possibilities to get an industry project financed from the green climate found. The highest CO2 benefits were from rice husk used in a cement kiln were half of the yearly rice husk production in Nepal could reduce the climate impact with 808000 tonnes CO2.
8.	Döse, Magnus, et al. (author) Effect on Radon Exhalation Rate Due to Cracks in Concrete 2019 In: Nordic Concrete Research. - : NORDIC CONCRETE FEDERAT. - 0800-6377 .- 2545-2819. ; 61:2, s. 79-90 Journal article (peer-reviewed)abstract The second largest cause of lung cancer in the World is related to radon (Rn-222) and its progenies in our environment. Building materials, such as concrete, contribute to the production of radon gas through the natural decay of U-238 from its constituents. The Swedish Cement and Concrete Research Institute (CBI), part of RISE (Research Institute of Sweden AB), has examined the effects of cracks in concrete on two different concrete recipes where an Ordinary Portland Cement, OPC-CEM-I concrete (REF) and an OPC concrete including a hydrophobic additive (ADD) were addressed. Two concrete prisms from each concrete recipe were examined. The radon exhalation rate was measured in the pristine state and after concrete cracks had been induced into the concrete prisms. Measurements were performed with an ATMOS 33 ionizing pulsation chamber. The results indicate a strong influence of cracks on the radon exhalation rate. An increase in radon exhalation rate was calculated for every test prism. The increase in radon exhalation rate varied between 80 and 260 %. The crack apertures may play a significant role on the exhalation rate. The concrete prisms with the largest apertures (ADD) also generated the highest radon exhalation rates. The results imply that there could be a substantial variation in the exhalation rate, due to numerous factors, but nonetheless, the results should, raise the awareness of the impact cracks in concrete structures, may have on the final exhalation rate of radon. The exhalation rate of the recipe with an additive (ADD) also showed a lower exhalation rate than for the reference recipe (REF), when compared in a pristine state. This was in part expected. However, the effect of induced cracks and its aperture, seemingly trumps the effect that an additive may play on the radon exhalation rate, when cracks are induced.The hypothesis is in part verified in view of the results of the prism for the ordinary Portland recipe (REF-prisms), were an increase of approximately 100 % would be expected due to the total surface increase. The results also indicate this. The major increase in the radon exhalation rate of the ordinary Portland recipe including an additive, implies however other factors, such as minor internal cracks, that may substantially contribute to the final exhalation rate.
9.	Flansbjer, Mathias, et al. (author) Meso Mechanical Study of Cracking Process in Concrete Subjected toTensile Loading 2018 In: Nordic Concrete Research. - Oslo : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 59:2, s. 13-29 Journal article (other academic/artistic)abstract This project focused on how the cracking process in concrete is influenced by both the micro and meso structures of concrete. The aim was to increase knowledge pertaining to the effect of critical parameters on the cracking process and how this is related to the material's macroscopic properties. A methodology based on the combination of different experimental methods and measuring techniques at different scales was developed. Crack propagation during tensile loading of small-scale specimens in a tensile stage was monitored by means of Digital Image Correlation (DIC) and Acoustic Emission (AE). After testing, crack patterns were studied using fluorescence microscopy.
10.	Geiker, Mette Rica, et al. (author) Screening of Low Clinker Binders, Compressive Strength and Chloride Ingress 2017 In: Nordic Concrete Research. - : Nordic Concrete Federation. - 0800-6377 .- 2545-2819. ; 57:2, s. 23-38 Journal article (peer-reviewed)abstract This paper reports an initial screening of potential new binders for concrete with reduced CO2-emission. Mortars cured saturated for 90 days are compared with regard to a) compressive strength of mortars with similar water-to-binder ratio, and b) chloride ingress in similar design strength mortars exposed to seawater. The reference used was a binder composition typical for a Danish ready mixed concrete for aggressive environments and strength class C35/45. Based on the present investigation and assumptions up to around 15% reduction in CO2 emission from binder production might be obtained without compromising the 90 days compressive strength and resistance to chloride ingress in marine exposure by using selected alternative binders.
11.	Gram, Annika, et al. (author) Evaluation of Crushed Fine Materials 2022 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 67:2, s. 65-77 Journal article (peer-reviewed)abstract As natural resources of sand and fine material used in the concrete industry are becoming more scarce, crushed materials are being used to a greater extent. Shape and texture of machine crushed materials differ from aggregates naturally ground, layered and sorted under the course of millions of years. It is assumed that crushed aggregates are more angular and of less smooth texture than natural aggregates, which will affect the flow behaviour of a suspension containing crushed material. In the mix design process of cementitous suspensions, an adequate rheology of the micro mortar (all constituents in the concrete being able to pass a 0.125 mm sieve, including the cement) is crucial. In this paper, the shape of fine particles is linked to the micro mortar plastic viscosity of the filler suspension including cement. The plastic viscosity here serves as an important quality assessment of the filler, since the micro mortar workability features are vital for the final mix design quality of the concrete workability.
12.	Hasholt, Marianne Tange, et al. (author) Nordic Concrete Research workshop : "Accelerated freeze-thaw testing of concrete", Lyngby, 20th April 2022 2022 In: Nordic Concrete Research. - : SCIENDO. - 0800-6377 .- 2545-2819. ; 66:1, s. 113-133 Journal article (peer-reviewed)abstract A one-day Nordic Concrete Research workshop on "Accelerated freeze-thaw testing of concrete" attracted approx. 30 participants. The workshop included presentations on various aspects, such as observed frost damage in the field and the importance of the temperature curve during testing as well as other interactions with the surroundings of the concrete. The workshop also included examples of recent research, which can improve our knowledge about the frost damage mechanism and therefore provide input to improving the standardised test methods. The present paper is a summary of the nine presentations and the discussion arising from the presentations.
13.	Hernández Vargas, Jose, et al. (author) Grading Material Properties in 3D Printed Concrete Structures 2022 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 66:1, s. 73-89 Journal article (peer-reviewed)abstract Functionally graded materials (FGMs) describe composite materials with a gradual change in properties along one or several axes. A major advantage with this approach is the avoidance of discontinuities between different layers of material. 3D Printing offers the possibility to control the material composition and spatial placement along the printing process to create structures with graded properties. However, there are very few examples of the application of this approach to 3D concrete printing (3DCP). This paper presents a review of the current approaches of and methods to grade the material properties of a 3DCP structure, as well as a review of similar methods used in other 3D printing processes. Finally, the potential applicability of these principles into concrete are presented and discussed.
14.	Khouri Chalouhi, Elisa, et al. (author) Topological and Size Optimization of RC Beam Bridges : An Automated Design Approach for Cost Effective and Environmental Friendly Solutions 2019 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 61:2, s. 53-78 Journal article (peer-reviewed)abstract This work presents a procedure for the automated design and optimization of reinforced concrete beam bridges. The aim is to find solutions that minimize the investment cost and the environmental impact of the bridge. The complete structure is optimized including: number of spans, pier locations, pier-deck connections and deck dimensions. A detailed design of the deck reinforcement is included as well. Furthermore, constructability is considered and quantified within the investment cost to avoid a merely theoretical optimization. Genetic Algorithm (GA) and Pattern Search (PS) optimization algorithms are used. To reduce the computational time and make the procedure more user-friendly, a memory system is integrated and a modified version of GA is developed. In this paper, the proposed procedure is applied to re-design an existing bridge originally designed according to Eurocodes by an experienced engineer in 2013. Savings of 1015% for both investment cost and environmental impact have been obtained. Finally, the proposed procedure has been applied to several alternatives with different total bridge lengths to suggest the optimal number of spans for a given total bridge length.
15.	Lindh, Per, et al. (author) Resonant Frequency Ultrasonic P-Waves for Evaluating Uniaxial Compressive Strength of the Stabilized Slag–Cement Sediments 2021 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 65:2/2021, s. 39-62 Journal article (peer-reviewed)abstract Marina sediment kan stabiliseras med ultrahöghållfasta bindemedel: cement, Cement Kiln Dust (CKD) och slagg. Egenskaperna hos den stabiliserade jorden indikerar potential för återanvändning. Den här studien undersökte prestandan för den enaxiella tryckhållfastheten (UCS) i smarina sediment stabiliserade med bindemedel (cement, CKD, slagg), testade med ultraljuds P-vågor. Material omfattar 194 prover insamlade från Göteborgs hamn. Experimentet utfördes av Sveriges Geotekniska Institutet (SGI). Tryckhållfastheten hos prover stabiliseras med olika förhållande av bindemedel (cement, CKD, slagg) testades med resonansfrekvenser (P-vågor). Korrelationsprofilerna för lågt vatten/hög bindemedel (LW/HB) cement/slagg (40/60 %) kontrollerades genom härdningstid. Simplextesten för slagg-cement-CKD visade UCS av prover med låg/hög vattenhalt och olika bindemedelsförhållande av cement (kg/m3). Förhållandet mellan cementbindemedel och härdningstid spelar en avgörande roll för ökningen av UCS följt av mekaniska egenskaper hos prover och spänningsintensitet. De högsta värdena 1000 m/s i P-vågor. Resultaten visade hög förklaringsgrad (97 %) och beröringsfritt tillvägagångssätt för att testa tryckhållfasthet hos stabiliserade sediment. Seismiska metoder fungerar bra och kan användas för att testa det stabiliserades sediment i labb och fält via seismisk CPT, ytvågsseismik eller cross hole seismik.
16.	Malm, Richard, 1980- (author) Full-scale test of an unreinforced concrete dome plug for the spent nuclear fuel repository 2018 In: Nordic Concrete Research. - : The Nordic Concrete Federation. - 0800-6377 .- 2545-2819. ; 58:1, s. 55-75 Journal article (peer-reviewed)abstract In the planned Swedish repository for spent nuclear fuel, plugs are designed to close the deposition tunnels. The outer part of these plugs consists of a concrete dome made with selfcompacting-concrete, designed to have low pH to reduce negative effects on the bentonite clay buffer. A full-scale test has been performed to evaluate the performance of the plug, to test the installation and to verify underlying design assumptions. In this paper, the behaviour of the concrete dome is evaluated based on measurements, from casting the concrete until it was subjected to 4 MPa hydrostatic water pressure.
17.	Nilforoush, Rasoul (author) A Refined Model for Predicting Concrete-Related Failure Load of Tension Loaded Cast-in-Place Headed Anchors in Uncracked Concrete 2019 In: Nordic Concrete Research. - : Sciendo. - 0800-6377 .- 2545-2819. ; 60:1, s. 105-129 Journal article (peer-reviewed)abstract Current theoretical models for predicting the concrete cone breakout capacity of tension loaded headed anchors do not consider the influence of member thickness, size of anchor head, and orthogonal surface reinforcement. In the present study, the influence of the aforementioned parameters was studied both numerically and experimentally. Both the numerical and experimental results showed that the tensile resistance of headed anchors increases by increasing the member thickness or if orthogonal surface reinforcement is present. In addition, the anchorage capacity further increases with increase of the anchor head size.The current model for predicting the concrete cone failure load of tension loaded headed anchors were refined and extended by incorporating three modification factors to account for the influence of the member thickness, size of anchor head, and orthogonal surface reinforcement. The accuracy of the proposed model was verified based on the results of 124 tests on single headed anchors from literature.
18.	Oliva Rivera, Alexander, et al. (author) Accelerated Carbonation of Binders Containing SCM at High CO2 Concentration 2023 In: Nordic Concrete Research. - : Nordic Concrete Federation. - 0800-6377 .- 2545-2819. ; 69:2, s. 1-10 Journal article (peer-reviewed)abstract Accelerated carbonation of recycled concrete aggregates (RCA) could be an efficient way to reduce the carbon footprint. High CO2-concentration under optimal relative humidity could accelerate the CO2 binding capacity of the hydrated cement paste in the RCA. The latter is the topic of this paper. The study looks into the forced carbonation of crushed cement pastes as a basis to understand the CO2 uptake in relation to various binders containing supplementary cementitious materials (SCM) such as fly ash (FA) and ground granulated blast furnace slag (GGBS). Samples include three cement pastes: ordinary Portland cement, substitution rate of 30 % FA and 50 % GGBS respectively at a water/binder ratio of 0.45. All binders were graded to 0/2, 2/4 and 4/8 mm fraction sizes and preconditioned before exposed to CO2 concentration of 10 % under controlled temperature at 20 C-degrees and 65 % RH. All tested binders presented a high CO2 uptake within the first hours of exposure with clear differences concerning the fraction sizes and the composition. The phase content before and after carbonation was observed by X-ray diffraction and the portlandite and calcite were quantified by thermogravimetric analyses and their derivative curves for fraction size 4/8 mm.
19.	Peterson, Viktor, et al. (author) Static and Dynamic Four-Point Flexural Tests of Concrete Beams with Variation in Concrete Quality, Reinforcement Properties and Impact Velocity 2021 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 65:2, s. 19-38 Journal article (peer-reviewed)abstract This paper discusses the results from three experimental test series previously conducted. The tests consist of quasi-static monotonic and dynamic four-point flexural tests on reinforced concrete beams. The effect of varying material and load parameters on the plastic strain distribution and energy absorbed by the reinforcement is discussed. The main findings are the significant effect of the post-elastic region of the steel reinforcement and the impact velocity during dynamic loading. The results will be used to validate and construct numerical models in future work, where the findings presented can be investigated further.
20.	Rajczakowska, Magdalena, et al. (author) Is Cement Paste Modified with Carbon Nanomaterials Capable of Self-Repair after a Fire? 2022 In: Nordic Concrete Research. - : Walter de Gruyter. - 0800-6377 .- 2545-2819. ; 67:2, s. 79-97 Journal article (peer-reviewed)abstract This manuscript presents preliminary results on the cement paste potential, with and without carbon nanomaterials, to heal high-temperature cracks. Cement paste beams were subjected to thermal loading of 200 & DEG;C and 400 & DEG;C after 28 days of water curing. High temperature caused the formation of microcrack networks on the specimen's surface. Self-healing was achieved by exposing the cracked samples to cyclic water immersion. The efficiency of the process was evaluated based on the crack closure and mechanical properties recovery after 24 days. The results indicated a distinct dependence of the healing on the loading temperature. Carbon nanotubes had a positive effect on self-repair efficiency.
21.	Roy, Rahul, 1996-, et al. (author) Encapsulation Techniques and Test Methods of Evaluating the Bacteria-Based Self-Healing Efficiency of Concrete : A Literature Review 2020 In: Nordic Concrete Research. - : Nordic Concrete Federation. - 0800-6377 .- 2545-2819. ; :1/2020, s. 63-85 Journal article (peer-reviewed)abstract Crack formation in concrete structures due to various load and non-load factors leading todegradation of service life is very common. Repair and maintenance operations are, therefore,necessary to prevent cracks propagating and reducing the service life of the structures.Accessibility to affected areas can, however, be difficult as the reconstruction and maintenanceof concrete buildings are expensive in labour and capital. Autonomous healing by encapsulatedbacteria-based self-healing agents is a possible solution. During this process, the bacteria arereleased from a broken capsule or triggered by water and oxygen access. However, itsperformance and reliability depend on continuous water supply, protection against the harshenvironment, and densification of the cementitious matrix for the bacteria to act. There are vastmethods of encapsulating bacteria and the most common carriers used are: encapsulation inpolymeric materials, lightweight aggregates, cementitious materials, special minerals,nanomaterials, and waste-derived biomass. Self-healing efficiency of these encapsulatedtechnologies can be assessed through many experimental methodologies according to theliterature. These experimental evaluations are performed in terms of quantification of crackhealing,recovery of durability and mechanical properties (macro-level test) andcharacterization of precipitated crystals by healing agent (micro-level test). Until now,quantification of crack-healing by light microscopy revealed maximum crack width of 1.80mmhealed. All research methods available for assesing self-healing efficiency of bacteria-basedhealing agents are worth reviewing in order to include a coherent, if not standardizedframework testing system and a comparative evaluation for a novel incorporated bacteria-basedhealing agent.
22.	Saback de Freitas Bello, Vanessa, et al. (author) Asset Management of Existing Concrete Bridges Using Digital Twins and BIM: a State-of-the-Art Literature Review 2022 In: Nordic Concrete Research. - : Walter de Gruyter. - 0800-6377 .- 2545-2819. ; 66:1, s. 91-111 Research review (peer-reviewed)abstract The need to optimize investments in bridge maintenance has created a demand for improved bridge management systems (BMS). Outdated practices in bridge inspection and constant advances in information technology have also contributed to this demand. The use of Digital Twins (DT), although well established in other industries, is still incipient for asset management and structural analysis of bridges. There is a great deal of research on Building Information Modelling (BIM) for bridge inspection, but its post-construction potential is still under-explored. This study presents a state-of-the-art review of the literature on asset management for bridges using digital models such as BIM and digital twins. The review was conducting using a systematic approach. Despite the rapid increase in research on DT and the amount of existing research on BIM, several gaps remain to be addressed, such as the lack of consensus about the definition of digital twins, which has led to wrongful categorisation of digital models as DT. The complex data flow and software compatibility required to develop a functional DT have hindered the exploitation of their full potential so far. The integration of BIM post-construction to BMS and existing automation technologies can also significantly improve current practices of bridge management.
23.	Sadagopan, Madumita, 1987-, et al. (author) Effects of Slag Addition and Mechanical Pre-Processing on the Properties of Recycled Concrete in Terms of Compressive Strength and Workability 2021 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 64:1, s. 11-29 Journal article (peer-reviewed)abstract Concrete waste as crushed concrete aggregates (CCA) in structural concrete prolongs the technical life of the reference concrete accomplishing closed loop recycling. CCA concrete reaches the reference concrete compressive strength and workability by the densification of CCA and cement paste. Our previous study demonstrates CCA densification by mechanical pre-processing, aggregate quality improvements discerned by increased packing density giving reference concrete strength and workability. This study addresses paste densification with blast furnace slag (GGBS) to replace 30 (wt.%) of Portland cement at reference concrete w/b ratio 0.5 and a lower w/b 0.42. Two CCA replacements are investigated: fine aggregates, CCA50; overall aggregate replacement, CCA100. Compressive strength results show that both CCA50, CCA100 mixes achieve reference values at w/b 0.42, only CCA100 achieves reference value at w/b 0.5 as a climate-optimized concrete. The CCA50 mix-w/b 0.5 reaches reference strength when paste densification by GGBS is combined with CCA densification from mechanical pre-processing of aggregates. The 7-day strength of CCA100 with GGBS increases by 11% by mixing with pre-soaked GGBS. Statistical analysis of CCA100 strength results shows significant improvements with GGBS compared to mechanical pre-processing. Significant improvements are possible in CCA50 mix for a combination of mechanical pre-processed aggregates and GGBS replacement.
24.	Sayahi, Faez, et al. (author) Plastic Shrinkage Cracking of Self-compacting Concrete: Influence of Capillary Pressure and Dormant Period 2019 In: Nordic Concrete Research. - : Norsk betongförening. - 0800-6377 .- 2545-2819. ; 60:1, s. 67-88 Journal article (peer-reviewed)abstract This research investigates the effect of capillary pressure and the length of the hydration dormant period on the plastic shrinkage cracking tendency of SCC by studying specimens produced with different w/c ratios, cement types and SP dosages.The results show, that the cracking tendency of SCC was the lowest in case of w/c ratio between 0.45 and 0.55, finer rapid hardening cement and lower dosage of SP. The dormant period was prolonged by increasing the w/c ratio, using coarser cement and higher SP dosage. It was concluded that the cracking tendency of concrete is a function of the capillary pressure build-up rate and the length of the dormant period.
25.	Silfwerbrand, Johan (author) Concrete and Sustainability - Some Thoughts from a Swedish Horizon 2020 In: Nordic Concrete Research. - : NORDIC CONCRETE FEDERAT. - 0800-6377 .- 2545-2819. ; 63:2, s. 79-87 Journal article (peer-reviewed)abstract Concrete production, especially the cement production, stands for 5-8 percent of the global CO2 emissions. Since concrete is the most frequently used man-made construction materials, this fact is not surprising. Concrete is also the only realistic alternative in order to improve the living circumstances in many countries around the world. Due to its size, the concrete sector has a great responsibility for limiting the consequences of the on-going climate change. The Swedish cement producer Cementa has an ambitious zero vision stating zero CO2 emissions in year 2030. The measures include energy efficiency, bio mass instead of fossil fuels, blended cements, CO2 uptake through carbonation and Carbon Capture Storage (CCS). This paper discusses these measures but also others such as optimization of the concrete mix, optimization of the structural geometry and prolongation of the service life. The paper is ended by a section on adaptation since concrete will also have an important role concerning protection of the built environment for climate change. Protection structures against flood, reconstruction of dams, new waste-water systems and bright permeable concrete pavements reflecting sunlight and improving drainage after heavy rain constitute some examples.
26.	Sjölander, Andreas, Ph.D, 1983-, et al. (author) Failure Mechanisms of Fibre Reinforced Shotcrete : Numerical Simulations Considering Local Variations in Thickness and Bond Strength 2022 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 2545-2819. ; 67:2, s. 51-64 Journal article (peer-reviewed)abstract Fibre-reinforced shotcrete is the most common support method for hard rock tunnels in the Nordic countries. The design of shotcrete is often based on empirical methods or simplified analytical equations, which neglect variations in mechanical properties and shotcrete thickness. Data collected from the field shows that significant variations in shotcrete thickness and bond strength should be expected during tunnel construction. However, how this affects the structural behaviour and capacity of the shotcrete lining is unknown. Moreover, the design philosophy for shotcrete assumes that the primary failure modes of shotcrete, i.e. bond and flexural failure, can be treated separately. This was derived based on observations of experiments in a laboratory environment. Therefore, the focus of a finalized doctoral project was to develop a numerical framework to simulate the structural behaviour of fibre-reinforced shotcrete in interaction with hard rock and rock bolts. The effect of variations in shotcrete thickness and bond strength was studied through numerical simulations to increase the understanding of its effect on the failure load of the lining. The results indicate that the most important parameter is the mean value of the shotcrete thickness and bond strength around a narrow perimeter of the block.
27.	Sjölander, Andreas, 1983-, et al. (author) In-Situ and Laboratory Investigation on Leaching and Effects of Early Curing of Shotcrete 2019 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 61:2, s. 23-37 Journal article (peer-reviewed)abstract During the construction of a rock tunnel in Stockholm, several sections with leaching shotcrete (sprayed concrete) were found one year after the spraying was completed. An investigation was therefore conducted, and its results are presented in this paper. The amount of leaching after such a short time indicated that a one-sided water pressure existed in combination with a permeable shotcrete. The reason for the water pressure was likely a partly unsuccessful grouting that created sections with leaking water. The permeable shotcrete could be a combined result of insufficient curing and the use of accelerators, and the effect of in-situ curing was therefore investigated. A total of six slabs were sprayed and cured under different conditions in the tunnel. Test results according to standards indicated that curing has no significant effect on the development of mechanical strength or water penetration through the shotcrete. However, this is believed to be a result of the test method rather than the non-existing effect of curing. Lastly, some modifications to the test standard were proposed for future studies of in-situ curing.
28.	Strömberg, Larissa, et al. (author) Making Concrete Pavements Competitive by Using the Standardized Framework for Comparisons of Infrastructure Projects in Terms of Cost-Efficiency and Climate Impact 2020 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 62:1, s. 21-39 Review (peer-reviewed)abstract espite the new Swedish client requirement to reduce the climate impact from the construction of roads, there has been relatively little research so far on how the optimization measures regarding the environmental impact of road pavements can be integrated in the traditional design. An increase in axle weights, changes of the traditional ways of travel, e.g. the use of automated and guided vehicles, and stricter customer requirements on reducing the climate impact require new approaches to steer the road and pavement industry towards more climate neutral solutions. This paper analyzes the latest standards for sustainability assessment of engineering works in an attempt to adjust these standards for assessing various road design options in a comparable and fair way, also when various materials are included.
29.	Veganzones Muñoz, José Javier, 1989-, et al. (author) Width and Edge Beam Effects on the Ultimate Behaviour of RC Bridge Overhangs 2019 In: Nordic Concrete Research. - : NORDIC CONCRETE FEDERAT. - 0800-6377 .- 2545-2819. ; 61:2, s. 131-152 Journal article (peer-reviewed)abstract The bearing capacity of RC overhangs under concentrated loads can be dependent on the width of the slab. The goal of this paper is to investigate the effect of different widths using tests from the literature and non-linear FE-simulations as a reference. Shear force redistributions along the loading process and the shear concrete capacity are analysed. The shear effective width and the influence of an edge beam are also addressed. The results show that the bearing capacity of RC overhangs increase with the width until a transition area is reached and the increase flattens. An increased shear distribution sideways and posterior redistributions under the loading process are enabled. The shear capacity of concrete increases with the width and for loads close to the root an arch effect is observed. The edge beam contributes to a further increase of the ultimate capacity for wide enough overhangs. The effect of the width and the edge beam is not only quantitative but also qualitative since the failure mode and the critical section are influenced. Existing formulation for shear effective widths should be revisited. Experimental tests used for this purpose should consider wide enough specimens to capture the real behaviour of a bridge overhang slab.
30.	Yaqoob, Saima, et al. (author) Evaluation of Rapid Repair of Concrete Pavements Using Precast Concrete Technology : A Sustainable and Cost-Effective Solution 2021 In: Nordic Concrete Research. - : Walter de Gruyter GmbH. - 0800-6377 .- 2545-2819. ; 65:2, s. 107-128 Journal article (peer-reviewed)abstract Concrete and asphalt are the two competitive materials for a highway. In Sweden, the predominant material for the highway system is asphalt. But under certain conditions, concrete pavements are competitive alternatives. For example, concrete pavements are suitable for high-traffic volume roads, roads in tunnels, concentrated loads (e.g., bus stops and industrial pavement). Besides the load-carrying capacity, the concrete pavement has many advantages such as durability (wear resistance), resistance against frost heave, environment (pollution, recycling, and low rolling resistance leading to fuel savings), fire resistance, noise limitations, brightness, evenness and aesthetics. Concrete pavements are long-lasting but need final repair. Single slabs may crack in the jointed concrete pavement due to various structural and non-structural factors. Repair and maintenance operations are, therefore, necessary to increase the service life of the structures. To avoid extended lane closures, prevent traffic congestions, and expedite the pavement construction process, precast concrete technology is a recent innovative construction method that can meet the requirement of rapid construction and rehabilitation of the pavement. This paper evaluates rapid repair techniques of concrete pavement using precast concrete technology by analysing three case studies on jointed precast concrete pavements. The study showed that the required amount of time to re-open the pavement to traffic is dramatically reduced with jointed precast concrete panels.

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