Laboratory Cast Research Articles

Experimental evaluation of the corrosion influence on the structural response of Gerber half-joints

The assessment of the Gerber half-joints (or saddles), widespread in the infrastructure heritage of different countries, is nowadays a topical problem since they are often affected by chloride corrosion phenomena due to their positioning under the deck joint. In this paper, the influence of steel rebar corrosion on the experimental response of Gerber half-joints is experimentally analysed and discussed. In particular, four elements were cast in Laboratory of University of Rome “Tor Vergata” two of which subjected to accelerated corrosion, and then tested up to failure. The specimens were designed with typical strut and tie models, with the aim of achieving different failure modes governed by the concrete crush or by the tensile rebar breaking. Particular care was devoted to the corrosion process, in order to simulate decay scenarios typical of these structures. The experimental outcomes, expressed in terms of load–displacement curves, crack patterns and failure mechanisms show that also medium-slight degree of pitting corrosion can cause great reductions in capacity and ductility of the saddles, modifying, in addition, their failure mechanism. Finally, from the experimental outcomes, the sensitivity of these peculiar structures, not only to the corrosion amount, but also to its spatial distribution among the different steel rebars, and its morphology (pitting or uniform corrosion) is clearly underlined. As a consequence, the necessity to accurately and properly account for the corrosion phenomenon in the structural assessment is remarked.

Fit of removable partial denture frameworks fabricated from 3D printed patterns versus the conventional method: An in vitro comparison

Statement of problemThe conventional method of fabricating removable partial denture (RPD) patterns is a time-consuming, expensive, and complex process, and the success of the treatment depends on the fit of the framework. Questions still remain as to whether the 3D-printing method is an acceptable procedure compared with the conventional method. PurposeThe purpose of this in vitro study was to compare the fit of RPDs cast from 3D printed frameworks and conventionally fabricated RPDs according to the gaps between the framework and the reference model. Material and methodsA metal reference model was made from a Kennedy class III modification 1 maxillary typodont. For the conventional group (n=9), impressions were made from the metal cast. Cobalt chromium frameworks were cast with the conventional method. For the digital group (n=9), the metal cast was scanned with a laboratory scanner, and the RPD was designed in the 3Shape platform. The standard tessellation language (STL) file of the design was downloaded to a 3D printer (Hunter DLP), and 9 resin frameworks were printed. These frameworks were invested and cast in the same dental laboratory as the first group. Gap measurement was assessed vertically with a superimposition software program (Geomagic Control X), and additional measurements were assessed under rests, reciprocal arms, and a 2.2-mm box under the major connector. The independent t test was used for determining the results and statistical analysis between groups. The paired t test was used for statistical analysis within groups (α=.05 for all tests). ResultsNo significant differences (P>.05) were observed in the mean ±standard deviation in overall fit according to the gaps in the conventional group (103 ±18 μm) and those in the digital group (109 ±21 μm). The biggest gap (poorest fit) was observed in the 2.2-mm box under the major connector (115 ±6 μm). ConclusionsBoth conventional and 3D-printing methods showed clinically acceptable fits. Further clinical studies with a larger sample size and long-term follow-up are needed.

Prosthesis-Implant Arch Area Ratio (PIAAR) - A New Geometric Paradigm, Replacing the Current 'A-P Spread' of a Cantilever in Full-Arch Implant Prosthesis: A Proof-of-Concept Experiment.

The anterior-posterior spread concept is relied upon to understand the bioengineering aspects of cantilevers in fixed complete denture prostheses. This concept is not evidence-based. With no other category existing in contemporary implant dentistry, this conventional anterior-posterior spread concept may have limited more precise and accurate biomechanical analysis. This paper aims to validate a scientific rationale for utilizing this new prosthesis-implant arch area ratio instead of the preexisting anterior-posterior spread concept. Utilizing the preexisting mathematical principle of "Heron's formula," enabling the calculation of the area of a triangle with three known lengths and no angular information, a new prosthesis-implant arch area ratio is introduced through algebraic derivation. Geometrically, three different sections of prosthetic cantilevers are defined as: (1) anterior cantilever; (2) lateral cantilever; (3) posterior cantilever. The prosthesis-implant arch area ratio is defined as the prosthesis arch area (anterior, lateral, or posterior cantilever) divided by the sum of the platform arch area and the selected prosthesis arch area. As a proof-of-concept experiment, fifteen different laboratory cast arches (n = 15) were chosen; theorized four implant platforms were referenced from the conventional anterior-posterior spread ration of 1:1.5, followed by calculating platform arch area and prosthesis arch area using Heron's formula. Then, three different horizontal arch width ratios (1:1, 1.25:1, and 1.5:1) under the constant linear height ratio of anterior-posterior spread (1:1.5) were drawn to assign different experimental groups of prosthesis arch area on each patient scenario, followed by cantilever comparison combining all ratio values (n = 45). One-way ANOVA and Tukey's post hoc multiple comparison tests were used for statistical analysis. One-way ANOVA revealed statistical differences of all prosthesis-implant arch area ratios on each cantilever group; anterior cantilever, F(2, 42) = 8.326, p = 0.0009; lateral cantilever F(2, 42) = 43.92, p < 0.0001; posterior cantilever, F(2, 42) = 26.66, p < 0.0001, as well as cantilever's comparison, F(2, 132) = 240.8, p < 0.0001. Tukey's post hoc test showed a statistically significant ascending trend of prosthesis-implant arch area ratio as the horizontal width ratio increases. Interestingly, the posterior cantilever had the greatest prosthesis-implant arch area ratio. Compared to the preexisting anterior-posterior spread concept, a new prosthesis-implant arch area ratio seemed to be a more categorized, geometric, and perceptive modality of assessing the prosthetic cantilever in a full-arch implant-supported prosthesis, allowing a more systematic indexing of different full-arch implant clinical scenarios with greater specificity and consistency.

Transformation of the δ-Ferrite in SS2343 Austenitic Stainless Steel upon Annealing at 1050 °C, 1150 °C and 1250 °C

The solidification behaviors of laboratory cast austenitic SS2343 stainless steel in terms of the volume fraction of δ-ferrite in the as-cast state and its transformation after subsequent annealing were investigated. Monitoring of morphological transformations of δ-ferrite in the microstructure show the progress of δ-ferrite dissolution. Annealing tests were conducted at 1050 °C, 1150 °C and 1250 °C with soaking times of 5 and 40 min. The thermodynamic prediction and metallographic identification of δ-ferrite are presented. The ferrite fractions were measured using a magnetic method and determined to be in the range between 10.7% and 14.6%. The volume share of δ-ferrite decreased with an increase in temperature and the time of annealing. About 50–55% the δ-ferrite was effectively transformed. The δ-ferrite phase, originally present in a dendritic morphology, tends to break up and spheroidize. The morphology varies from vermicular, lacy and acicular shapes to globular for higher temperatures and for longer exposure times. In the δ-ferrite after annealing, concentrations of Cr and Mo decrease, and conversely the concentration of Ni increase, all by small, but significant, amounts. The observed changes in the solute concentration can be explained in terms of the transformation of ferrite into austenite and sigma phases.

Accuracy of a milled digital implant surgical guide: An in vitro study

Statement of problemAn accurate surgical template for guided implant surgery is essential for the success of an implant restoration. However, reports on the accuracy of digitally designed and computer numeric controlled (CNC) machine-milled surgical templates are sparse. PurposeThe purpose of this in vitro study was to investigate the accuracy of an implant surgical guide digitally designed by using data from cone beam computed tomography (CBCT) scans and milled with a 5-axis CNC machine. Material and methodsSix representative radiographic templates were prepared from radiopaque resin plates. For each guide, a CBCT scan was made, and the extracted Digital Imaging and Communications in Medicine (DICOM) data were imported into a planning software program (ORGANICAL Dental Implant). Nine implants were virtually designed for each guide. The design data were imported into a 5-axis CNC machine, and the radiographic guides were fixed onto the CNC machine (Organical Multi S). Bore holes for surgical guide sleeves were milled directly in the radiographic template, which was converted into a surgical template. After the milling process, the surgical guides were scanned by using a laboratory cast scanner. The deviation between the position of the sleeve bore hole in the milled template and that in the virtual implant planning was digitally calculated. ResultsThe mean global deviation of the surgical guide was 0.16 ±0.06 mm in the circle center of the sleeve top, and the mean angular deviation was 0.61 ±0.40 degrees. The sleeve-implant distance and the sleeve axis angle showed no significant influence on the in vitro accuracy of the implant surgical guide. ConclusionsThe mean deviation of the surgical guide prepared by using the virtual planning software program and 5-axis CNC milling procedure in this study was 0.16 ±0.06 mm in the center of the sleeve top. Thus, the guide had acceptable precision.

Performance of Exterior Column Beam Connections as built at site

Comparing performance of ill detailed and ductile detailed connections as per IS: 13920 was the prime aim of this study. It was by and large observed during literature review that, usually investigations are done at laboratory casting and curing conditions. How-ever, site conditions are grossly different from laboratory conditions. It is a general experience that the ductile detailing is rarely followed at site. Thus it was felt necessary to investigate performance of such ill detailed constructions at site testing conditions. Specimen for this experiment were manufactured by site people at site conditions and cured at site conditions. A 6-storied MRF constructed in Satara (IS: 1893, Zone 3) was analyzed. An exterior column-beam connection from first slab was chosen for assessment. Design for seismic requirements was carried out referring to suggestions from latest revisions of IS :1893 and IS: 13920. Four 0.3:1 scaled down specimen from actually site sourced concrete and steel were constructed. Out of the four, two were detailed as per actual site practice. Two specimen were detailed as per IS:13920. Specimen were subjected to reverse cyclic displacement loading protocol. It was observed that latest revisions from IS codes ensure that beam fails prior to the connection. Overall performance characteristics were seen improved in case of ductile detailed connections.

MgO-Lignin Dual Phase Filler as an Effective Modifier of Polyethylene Film Properties.

Functional magnesium oxide-lignin hybrid materials were obtained via mechanical grinding. Their particle shape and size as well as physicochemical properties were characterized. MgO-lignin materials with biocomponent content (between 20% and 80% amount of total weight of filler) were used as a partially bio-structured modifier of low density polyethylene. The composites with 5% by weight of dual fillers and polyethylene grafted with maleic anhydride were compounded in a twin screw extruder working in co-rotating mode. The prepared blends were cast extruded using a single screw extruder and laboratory cast line. The properties of the obtained films were verified in case of their weldability. The seal strength as well as shear test and tear strength of the welded sheets were examined. The results showed that the shortest equivalent time required to perform correct weld occurred in the system, where the highest amount of lignin was used in hybrid filler MgO-L (1:5 w/w). From mechanical tests of welds, a sharp increase in ultimate seal force was noticed for almost all compositions with lignin, especially where MgO was coupled with a high lignin content. For those composition seal open force raised up to 37.0 N, from the value of 23.6 N, achieved for neat low density polyethylene (LDPE). Tear strength of weld sheets confirmed once more that LDPE composition with MgO-L (1:5 w/w) achieved the highest ultimate force with its value of 71.5 N, and it was ~20.0 N higher than in the case of neat LDPE.

Improvement of properties of cellulose dielectrics by their structure modification with nanocellulose produced of wastes of agricultural crops

A comparative study of laboratory castings of insulating paper was fulfilled: the traditional composition made of insulating cellulose of pine and cellulose, modified with the nanocellulose of the agricultural waste (composite). The positive effect of the introduction of this structure-forming modifier on the electrical and mechanical strength of the cellulose dielectric, as well as its heat resistance was revealed. Confirmation of expediency of development of works of this direction for expansion of raw material base for producing of the bio component promoting increase of working capacity of the cellulose dielectrics used in high-voltage insulation of power devices is received.

The effect of microalloying elements on prior austenite grain growth of low-carbon slab material

The effect of microalloying elements on the prior austenite grain growth of slab materials during slab reheating has been investigated. The investigated materials were laboratory castings with two levels of carbon (0.05 and 0.09 wt.%) and different combinations of microalloying elements, such as V, Nb, Mo and Ti. Experimental results were compared to equilibrium Thermo-Calc® simulations predicting the solubility of different precipitates during slab reheating. Based on slab reheating experiments at temperatures between 1100 – 1250 °C, Ti is the only alloying element to hinder prior austenite grain growth effectively above 1200 °C. For the steel containing high carbon with Nb, V and Ti microalloying, the average prior austenite grain size was less than 50 μm after the slab reheating to 1250 °C, which can be considered very small. According to Thermo-Calc® calculations, stable Ti(CN) precipitates are formed from the liquid and are in solution until 1500 °C. Until 50-60 % of soluble NbC -precipitates, austenite grain size remained relatively small in Nb-alloyed compositions without Ti, but after that grain size increased drastically. For only V-alloyed steels, already at the soaking temperature of 1100 °C hardly any VC precipitates exists based on Thermo-Calc® simulations, and after that grain coarsening can be assumed to be controlled only by the coarsening rate of austenite grains.

(Invited) Polymer Resistive Electronic Memory: Exploiting Bistability of Current-Voltage Characteristics

Electronic memory elements represent indispensable components of most electronic circuits. For some applications, like RFID tags used for smart packaging, for manufacturing and warehouse automation or security systems, simple low-level performance devices are required, which could be produced by cheap large scale production technology, as e.g. printing. We focus on resistor-type memory (ReRAM) made from switchable resistive materials. Unlike transistor and capacitor memory devices, ReRAM does not require a specific cell structure, which is difficult to prepare by printing. ReRAM is a simple two electrode device based on a sandwich structure, in which data are stored as different electrical conductivity states. Electrical bistability usually arises from changes of the intrinsic materials properties, such as charge transfer, phase change, conformation change and reduction–oxidation (redox) reaction, in response to an applied electric field. The basic memory cells can be integrated into a cross-point memory array, where each memory cell is unambiguously identified by its x and y coordinates, suitable for easy programming and reading the addressed cell. We show the preparation and properties of simple organic memory elements based on thin films of soluble polymers, which can be prepared using common laboratory casting techniques as spin casting, slot die or dip coating, or screen and inkjet printing in the manufacturing scale. Two systems are presented: (i) Molecularly-doped polymer based on a soluble derivative of polydiketopyrrolopyrrole mixed with a soluble low-molecular weight derivative of perylene sandwiched between ITO and Al electrodes shows pronounced hysteresis in its current voltage characteristics. Depending on the composition, the maximum achieved ON/OFF ratio was about 5 with writing/erasing voltage +/-5 V and reading voltage 0.5 V. The functionality of the structure as rewritable resistive memory is well documented on repeated read-write cycles and a retention time exceeding several hours. The properties of the memory element were further improved by the incorporation of a very thin insulating layer of high-k dielectrics containing molecular groups with high permanent dipole. Such elements reached the ON/OFF ratio about 103. (ii) A single component polymer rewritable resistive memory was prepared using a newly synthesized poly(N-(3-(9H-carbazol-9-yl)propyl)methacrylamide) sandwiched as a thin film between ITO and Al electrode. The polymer was prepared by a radical polymerization of the N-(3-(9H-carbazol-9-yl)propyl)methacrylamide using azobisisobutyronitrile as a radical initiator. The starting monomer was obtained by three-step reaction from carbazole. The molar mass of the polymer was influenced in limited extent by the reaction temperature but it was still relatively low (M w = 6000, M n = 4000, Ð = 1.50). However, the film forming abilities were sufficient, particularly in thin films (typical thickness used in the memory elements was below 100 nm). The polymer is stable at higher temperatures up to 300 °C, glass transition temperature of the polymer is 130 °C. The device showed good hysteresis in I-V characteristics with switching effects, maximum ON/OFF ratio ~ 200..A typical write/erase cycle is shown in Fig. 1 showing a good retention time exceeding 2 hours even during permanent reading in both ON and OFF states. Here, writing was at the applied voltage +5 V erasing with -5 V and reading at 0.5 V (sign refers to the polarity of the ITO electrode). After some initial instability during memory element forming, the ON and OFF current was stable during more than 40 repeated write/erase cycles. Work supported by the Grant Agency of the Czech Republic, project No.17-03984S Figure 1

Volume-Averaged Modeling of Multiphase Flow Phenomena during Alloy Solidification

The most recent developments and applications in volume-averaged modeling of solidification processes have been reviewed. Since the last reviews of this topic by Beckermann and co-workers [Applied Mech. Rev. 1993, p. 1; Annual Rev. Heat Transfer 1995, p. 115], major progress in this area has included (i) the development of a mixed columnar-equiaxed solidification model; (ii) further consideration of moving crystals and crystal dendritic morphology; and (iii) the model applications to analyze the formation mechanisms of macrosegregation, as-cast structure, shrinkage cavity and porosity in different casting processes. The capacity of computer hardware is still a limiting factor. However, many calculation examples, as verified by the laboratory casting experiments, or even by the casting processes at a small industrial scale, show great application potential. Following the trend of developments in computer hardware (projection according to Moore’s law), a full 3D calculation of casting at the industry scale with the multiphase volume-averaged solidification models will become practically feasible in the foreseeable future.

Properties of silica sand and GBF slag moulds practiced by Nishiyama process

ABSTRACTInvestigations were carried out to use Granulated Blast furnace (GBF) slag as mould material for either full or partial replacement of existing silica sand in foundry industry. Nishiyama process was adopted for evaluating the same. A series of sand tests were carried out on sand and slag individually and also combinations of these two. Three types of moulds were made with sand, slag individually and combination of these two. Both laboratory and industrial castings of ferrous and non ferrous materials were performed. Results of mould permeability, compression and shear strength of GBF slag reveal that is a suitable candidate for either partial or full replacement of molding sand. During casting of both laboratory and industrial, neither fuse, dripping nor collapse of the mould walls was observed; this is true for both ferrous and non ferrous castings. Castings with good surface finish, no surface defects and porosity were made by slag moulds.

Strength development of GGBS and fly ash concretes and applicability of fib model code’s maturity function – A critical review

This paper is the joint work of working group 4 of the RILEM TC 238-SCM and the fib Task Group 4.6. It was the aim of this literature study to quantify the effect of ground granulated blast furnace slag (GGBS) and silicious fly ash (sFA) on strength development of concrete. For the strength development the approach of the fib Model Code was chosen, which is based on an e-function that can be adapted to the strength development of an individual binder by selecting the so-called s-value based on the strength class of the Portland cement used. No guidance is provided for s-values for supplementary cementitious materials (SCMs). In order to determine the s-values for mixes with SCMs, a database was set up with results of material testing from literature. A relationship between s-values and w/b plus SCM/b ratios has been determined. This has been tested on laboratory cast specimens with 50 and 30% cement replacement with GGBS and FA respectively. These were cured at 20 °C. The s-values from this relationship were compared to those obtained from regression analysis and they were found to be satisfactory. This increased confidence in their use for predicting the strength development of other curing regimes, i.e. adiabatically cured concrete cubes, using the maturity function in the fib Model Code. Predictions of the effect of curing temperature, i.e. the adiabatic temperature history, on the strength development were again satisfactory. These were not significantly affected by the fib model code’s use of one value of “apparent” activation energy.

Effect of fly ash and plastic waste on mechanical and durability properties of concrete

The disposal of polythene waste and fly ash is causing serious threat to the environment. Aim of this study is to decrease environmental pollution by using polythene waste and fly ash in concrete. In this study, cement was partially replaced with 0%, 5%, 10%, 15% and 20% fly ash (by weight) and plastic waste was added in shredded form at 0.6% by weight of concrete. The specimens were prepared for the concrete mix of M25 grade and water to cementitious material ratio (w/c) was maintained as 0.45. Fresh concrete property like workability was examined during casting the specimens. Hardened properties were found out by carrying out the experimental work on cubes, cylinders and beams which were cast in laboratory and their behavior under test were observed at 7 & 28 days for compressive strength and at 28 days for density, flexural strength, dynamic modulus of elasticity, abrasion resistance, water permeability and impact resistance. Overall results of this study show that addition of 0.6% (by weight of the concrete) plastic waste with 10% (by weight of cement) replacement of cement by fly ash result an improvement in properties of the concrete than conventional mix.

Shear-thinning behavior of the CaO–SiO2–CaF2–Si3N4 system mold flux and its practical application

Satisfying the mold-flux performance requirements for high-speed continuous casting necessitates the development of a new non-Newtonian-fluid mold flux with shear-thinning behavior, i.e., a mold flux whose viscosity is relatively high under lower shear rates and relatively low under higher shear rates. In this work, a mold flux that exhibits shear-thinning behavior was developed by adding different amounts of Si3N4 to the CaO–SiO2–CaF2 mold flux. The shear-thinning behavior was investigated using a rotational viscometer. In addition, the microstructure of the newly prepared slags was studied by high-temperature Raman spectroscopy and X-ray photoelectron spectroscopy. The results showed that the mechanism of shear-thinning was attributable to a temporary viscosity loss caused by the one-way shear stress, whereas the corresponding magnitude of shear-thinning was closely related to the degree of polymerization (DP). Finally, the non-Newtonian fluid mold flux was used for laboratory casting tests, which revealed that the mold flux could reduce slag entrapment and positively affect the continuous casting optimization.

Kinetics of static recrystallization in the coarse-grained Fe–40 at.%Al–Zr–B alloy

The aim of works was to describe mathematically the kinetics of static recrystallization of the alloy type Fe–40at.%Al–Zr–B (with 24.6 Al–0.01 B–0.18 Zr–0.01 C in wt.%) with the coarse-grained structure. The microstructure of the laboratory castings made of this extremely brittle alloy was homogenized by hot rolling of the material in the protective capsules and by the long-term annealing at 1200°C. An initial microstructure with average grain size 0.77±0.27mm was obtained. Based on the isothermal plastic deformation tests and EBSD analysis, the static recrystallization kinetics of the prepared coarse-grained B2 iron aluminide after strain 0.20 was mathematically described. Recrystallized fraction depends on deformation/annealing temperature (900–1100°C) as well as on annealing time. The activation energy of static recrystallization was calculated as 255kJmol−1. Competition between dynamic recovery and static recrystallization was proved after strain 0.35 and annealing temperature 1100°C. Static recrystallization starts relatively easily in the studied alloy, but a very long-term annealing is quite necessary for the complete course of recrystallization. The mean size of recrystallized grains falls with the decreasing annealing temperature (0.47±0.15mm for temperature 1100°C, and 0.22±0.04mm for 900°C). Even at a temperature of 1200°C the annealing after deformation should last approx. 1min for obtaining the fully recrystallized microstructure. That is why the standard hot forming technologies should be combined by an interpass annealing in order to refine sufficiently the coarse grains.

Granulated Blast Furnace Slag: Potential Sustainable Material for Foundry Applications

Investigations were carried out on the suitability of granulated blast furnace slag as a mold material for either full or partial replacement of existing silica sand in the foundry industry. The sodium silicate-CO2 process was adopted for evaluating the same. A series of sand tests were performed on silica sand and slag individually and in combination. Three types of molds were prepared with slag and silica sand individually and in combination with 10% sodium silicate and 20 s of CO2 gassing time. A356 alloy and cast iron castings were performed on these newly developed slag molds. Both laboratory and industrial castings were performed. Results reveal that the mold properties of slag make them a suitable candidate for either partial or full replacement of molding sand. During casting, neither fusing, nor dripping, nor collapse of the mold walls was observed. Castings with good surface finish, no surface defects, and without porosity were made by slag molds.

A Statistics-Based Cracking Criterion of Resin-Bonded Silica Sand for Casting Process Simulation

Cracking of sand molds/cores can result in many casting defects such as veining. A robust cracking criterion is needed in casting process simulation for predicting/controlling such defects. A cracking probability map, relating to fracture stress and effective volume, was proposed for resin-bonded silica sand based on Weibull statistics. Three-point bending test results of sand samples were used to generate the cracking map and set up a safety line for cracking criterion. Tensile test results confirmed the accuracy of the safety line for cracking prediction. A laboratory casting experiment was designed and carried out to predict cracking of a cup mold during aluminum casting. The stress–strain behavior and the effective volume of the cup molds were calculated using a finite element analysis code ProCAST®. Furthermore, an energy dispersive spectroscopy fractographic examination of the sand samples confirmed the binder cracking in resin-bonded silica sand.

Mechanical performance of roller compacted concrete with recycled concrete aggregates

Because the recycling of construction and demolition waste (CDW) has been deemed to be a priority, the use of a recycled aggregate has been widely demonstrated as a sustainable contribution among different materials applied in civil projects. Roller compacted concrete (RCC) applications offer technical, economic and ecological solutions in many civil construction projects. To the best of the authors’ knowledge, there has been little research on the use of RCC with a coarse recycled aggregate that does not originate from pavement. This research evaluates the use of recycled concrete aggregates (RCA) from a CDW recycling plant in RCC mixtures. Four series of RCC mixtures were produced with different cement contents (110, 175, 250 and 350 kg/m3). Each series consisted of three mixtures with different RCA incorporation ratios (0%, 50% and 100%) of natural coarse aggregates, thus producing 12 RCC mixtures to evaluate the effect on the compaction, the mechanical and physical properties while highlighting a new laboratory casting method for flexural strength and drying shrinkage tests. Based on the obtained results, the use of coarse RCA in RCC production is feasible at a replacement level of 100% when using these materials in road pavement bases.

Flow of fresh concrete through reinforced elements: Experimental validation of the porous analogy numerical method

Numerical simulations of concrete castings are complex and time consuming. In order to decrease simulation time and to simplify simulation procedure, an innovative modelling approach, which treats reinforced sections in a formwork as porous media, was proposed. In the previous studies, this numerical model was proved suitable to simulate casting of model yield-stress fluids through reinforced elements. This article focuses on the experimental validation of the proposed model at the concrete scale. For this purpose, a large-scale laboratory casting of a highly reinforced beam is performed. The casting process is numerically simulated and the numerical results are compared to the experimental measurements.