Four-point Bending Method Research Articles

Experimental study of asphalt mixtures with recycled resources: Influence of electric arc furnace slag aggregate roughness and bitumen film thickness on fatigue performance

Electric arc furnace slag (EAFS) is a viable alternative in asphalt mixtures due to its favourable mechanical properties. This study examines the impact of EAFS content and bitumen film thickness (TF) on the fatigue performance of asphalt mixtures. Mixtures with varying levels of EAFS replacement were designed, and their mechanical properties were evaluated through indirect tensile strength and stiffness tests, followed by fatigue tests using the four-point bending method and EBADE (Strain Sweep Test). The results indicated that mixtures with EAFS exhibited increased stiffness, but fatigue performance decreased at high strain levels. At low strain levels, EAFS mixtures performed similarly or better than the control. HMA_GL had the highest TF (13.97 μm), followed by HMA_GS (13.60 μm), HMA_SL (12.66 μm), and HMA_SS (11.77 μm), showing that as the EAFS content increases, the TF decreases. This finding was verified through Digital Image Analysis. This decrease in TF is due to the high porosity and roughness of the EAFS, which in turn reduces the effective bitumen (Pbe) in the mixture. HMA_SL*, with a TF equal to the control, demonstrated a 22 % improvement in fatigue performance compared to HMA_SL. In the EBADE tests, HMA_GL achieved 44.69 MJ/m3 of dissipated energy, HMA_GS 31.55 MJ/m3, HMA_SL 34.45 MJ/m3, and HMA_SS 35.54 MJ/m3. The improved HMA_SL* recorded 42.15 MJ/m3, nearly matching the control. EBADE results confirmed that higher EAFS content increased initial stiffness, but the complex modulus (|E*|) decreased more rapidly as deformation increased. These results are consistent with the stiffness tests. These findings suggest that EAFS can successfully replace natural aggregates in asphalt mixtures, with a moderate increase in bitumen content recommended to improve fatigue performance.

Comparative Testing of Asphalt Concrete for Fatigue Life Using Various Modern Laboratory Methods

Statement of the problem. At present, one of the most significant tasks in the road industry is the actua-lization of the methodology for designing flexible pavements. In order to ensure extended pavement service life, design issues are of particular relevance, which requires the improvement of existing and the development of new calculation criteria, one of which is the calculation of asphalt concrete layers for fatigue life. Results. Comparative tests of various types of asphalt concrete selected at road construction sites were carried out using modern laboratory methods to evaluate their fatigue properties. The dependences between the relative tensile deformation of asphalt concrete and the number of load application cycles during tests by various methods are obtained. Conclusions. Through the course of the research, possible reasons for the heterogeneity of the results obtained on four-point bending installations were identified. For further research, the indirect stretching method is set forth as the main method, as it provides greater uniformity and determinism of the results, and the four-point bending method is proposed to be considered as an additional one, confirming the results obtained with indirect stretching.

Flexural vibration test method for determining the dynamic elastic modulus of full-size strawboards for use in transportation framed cases

This paper proposes an improvement in the test method for determining the flexural dynamic modulus of elasticity of strawboard with two triangular prisms as supports, for quality control and classification. Free-plate modal and free-plate transient excitation methods were used to test the elastic modulus of 1/4-plate and whole-plate strawboards. The dynamic test results were verified with the four-point bending method and tensile method. The results show that the elastic moduli of strawboards is approximately 2 GPa. The dynamic test method proposed is efficient, simple, repeatable, and accurate. This method is more suitable for factory applications than existing dynamic testing methods. The framed cases produced by the strawboard all meet the performance requirements in GB/T 7284 (2016).

Combined deterioration effects of freeze–thaw and corrosion on the cyclic flexural behavior of RC beams

Reinforced concrete (RC) stands as the predominant construction material, and with the growing prevalence of aging infrastructure, the safety assessment of deteriorating structures has emerged as a pressing and critical concern. This study presents an experimental investigation into the combined effects of freeze–thaw cycles (100, 200, and 300 cycles) and corrosion (corrosion ratio: 3% and 10%) on the cyclic behavior of RC beams. Seven RC beam specimens with varying types and levels of deterioration were fabricated, and static tests were conducted using a four-point bending method to assess the behavior of RC beams under each degradation factor. The experimental results revealed that increasing freeze–thaw cycles significantly impact RC beam behavior, leading to intensified crack formation due to cyclical frost-heaving pressure. This ultimately results in reduced yield loads ranging from 3% to 11% and peak loads reduced by 1–2% compared to the reference specimen A-0-0. Corrosion of steel bars in RC beams alters failure modes, with corroded specimens (C-0-3 and C-0-10) experiencing substantial decreases in yield load, a 15% reduction in C-0-3, and a 26% decrease in C-0-10, compared to A-0-0. Displacement at yield load and peak load also decreased, highlighting the detrimental impact of corrosion on beam mechanical properties. The combined deterioration from freeze–thaw cycles and corrosion further exacerbates these reductions, resulting in a substantial decrease in yield load (32%) and peak load (24%) in D-3-10 compared to the reference specimen A-0-0. Additionally, energy dissipation capacity and cumulative energy dissipation capacity exhibit dynamic changes influenced by the progression of freeze–thaw cycles, corrosion, and their combined effects.

Bending behavior of diamane and twisted bilayer graphene: Insights from four-point bending deformation

The intriguing physical properties of two-dimensional (2D) nanomaterials make them promising building blocks for flexible electronics. Using a four-point bending approach, this work establishes a comprehensive understanding of the bending behavior of diamane – a 2D diamond nanostructure, from elastic deformation to structural failure through atomistic simulations. The four-point bending method accurately reproduces the pure bending of the sample, and the obtained force-displacement curve fit well with the classical Euler beam theory. Structural failure is observed from diamane under bending when its thickness or the number of layers increases. Atomic insights reveal that the crack initiates from the tension side of the sample, resulting in a tension-induced bending failure. Specifically, the bending limit is found to be slightly larger than the fracture strain under tensile deformation. Additionally, the bending behaviour of the diamane analogous – twisted bilayer graphene with interlayer-bonding (TBGIB), has been investigated. Different from diamane, TBGIB bends elastically at the initial stage and then experiences structural failures with increasing bending strain. Higher interlayer bonding density is observed to result in a higher bending stiffness. Meanwhile, significant interlayer shear strain is detected during bending, which leads to interlayer bond breakage, rippling, and buckling of the graphene layer. This work provides a full description of the pure bending behavior of diamane and its analogous structure, which could be beneficial for their applications in flexible electronics.

Experimental assessment on cyclic flexural behavior of UHPC beam reinforced with negative Poisson’s ratio (NPR) steel rebar

The objective of this study is to experimentally explore the implication of an innovative steel rebar with negative Poisson’s ratio effect (termed as NPR steel rebar) on ultra high performance concrete (UHPC) beam under cyclic loading. Distinctly from conventional steel rebar, NPR steel rebar employed in this research inherently owns high ultimate tensile strength of approximately 1100 MPa, high uniform elongation of around 40% and superior durability. Four reinforced UHPC beams are conducted and tested under monotonic/cyclic loading through the four-point bending method. The structural characteristics of all specimens are discussed via failure mode, hysteretic curve, envelop response, stiffness degradation, energy-dissipating capacity, and steel strain evolution and etc. The results show that reinforced UHPC beam longitudinally configured with NPR steel rebar is available to exhibit satisfactory and superior monotonic/cyclic flexural performance. Firstly, the final failure mode of reinforced UHPC beam with NPR steel rebar exhibits multiple (7–8) closely-spacing localized cracks distributing within the pure bending section whether under monotonic or cyclic loading. Additionally, the superior mechanical performance of NPR steel rebar endows reinforced UHPC beam with high flexural capacity, high deformability, excellent stiffness degradation control, and outstanding energy dissipation capacity under cyclic loading. In which, the flexural capacity of UHPC beams reinforced with NPR steel rebar have been upgraded approximately by 47.8%, 52.3% under monotonic and cyclic loading respectively, compared with that of UHPC beams reinforced with HRB 400 steel rebar, meanwhile, the comparison for the energy dissipation capacity is emphasized in stages. Finally, the deflection prediction method for UHPC beam reinforced with NPR steel rebar at normal service stage under monotonic/cyclic loading is proposed. The results of this study provide valuable information for attaining a preliminarily comprehensive understanding of the structural behavior of reinforced UHPC members with NPR steel rebar under monotonic/cyclic loading, and the proposed combination of UHPC and NPR steel rebar provides a new idea for seismic toughness design of anti-bending structural components as well.

Flexural behavior of circular concrete filled steel tubular members strengthened by CFRP sheets

The flexural behavior of CFRP-strengthened circular concrete filled steel tubular (CFRP-C-CFST) members was investigated experimentally and theoretically. A total of nine specimens were tested through four-point bending method, including a comparative CFST specimen without CFRP strengthening (C-CFST), and eight CFRP-C-CFST specimens. Based on experimental results, the effects of different CFRP wrapping length, number of CFRP layers and wrapping schemes on the flexural behavior of the CFRP-C-CFST specimens are analyzed. Two failure modes, including CFRP debonding and CFRP fracture, are observed from the tested CFRP-C-CFST specimens. Increasing the length of CFRP delays debonding, while increasing the number of CFRP layers causes debonding to occur earlier. The flexural capacity of CFRP-C-CFST specimens with two-four CFRP layers is increased by about 20%-70% compared to the C-CFST specimens. A theoretical model based on fiber element method is proposed. This model considers the bi-directional stress state of the steel tube and the effect of bending moment on the confinement factor. A representative test result is selected to calibrate the distribution law of the confinement factor, and all the test results are predicted based on the calibrated parameters. The comparison between the predicted and the test results shows that the fiber element model can simulate the bending moment-deflection curves of C-CFST and CFRP-C-CFST members, and hence it can predict the flexural capacity, stiffness and ductility accurately.

Stress-dependent sintering behavior of porous thermal barrier coatings

Thermal barrier coatings (TBCs) are subjected to high temperature and complex stress fields during service in gas turbines. In this process, densification and hardening take place as the result of sintering, which is sensitive to boundary condition/external load. The stress-dependent sintering behaviors of porous TBCs were investigated in this work using a customized four-point bending method. Furthermore, stress-dependent sintering model was developed and implemented in finite element analysis to elucidate sintering mechanisms. It was found that stress gradient induced nonlinear differential sintering behavior, due to the accelerating and retarding effects of compressive and tensile stresses, respectively. In addition, microstructure-mechanical property relation was determined following the exponential law and high-throughput method was proposed for the characterization of stress dependence. The in-depth understanding of stress-dependent sintering behavior could provide guidance to the design and failure analysis of TBCs applied on complex shaped components in the hot section of gas turbines.

An In-Situ Tester for Extracting Piezoresistive Coefficients

In this study, an electrostatic force-driven on-chip tester consisting of a mass with four guided cantilever beams was employed to extract the process-related bending stiffness and piezoresistive coefficient in-situ for the first time. The tester was manufactured using the standard bulk silicon piezoresistance process of Peking University, and was tested on-chip without additional handling. In order to reduce the deviation from process effects, the process-related bending stiffness was first extracted as an intermediate value, namely, 3590.74 N/m, which is 1.66% lower than the theoretical value. Then, the value was used to extract the piezoresistive coefficient using a finite element method (FEM) simulation. The extracted piezoresistive coefficient was 9.851 × 10−10 Pa−1, which essentially matched the average piezoresistive coefficient of the computational model based on the doping profile we first proposed. Compared with traditional extraction methods, such as the four-point bending method, this test method is on-chip, achieving automatic loading and precise control of the driving force, so it has high reliability and repeatability. Because the tester is manufactured together with the MEMS device, it has the potential to be used for process quality evaluation and monitoring on MEMS sensor production lines.

Cantilever plate mid-span patch method for dynamically testing the in-plane Poisson's ratio of oriented strand board

A cantilever plate span-to-span patch method was proposed and demonstrated for dynamic testing of OSB Poisson’s ratio with high testing accuracy, simplicity, ease of implementation, and effectiveness. It is based on the patch method with zero transverse stress equal to the cantilever plate. Its effectiveness was verified by the four-point bending method and the patch strain gauge method with zero transverse stress. The simulation and theoretical analysis showed that the relative errors of OSB longitudinal and transverse Poisson’s ratios dynamically tested by the span-in patch method and the patch method with zero transverse stress were within ±3.8%. The OSB longitudinal and transverse Poisson’s ratios dynamically tested by the span-in patch method were in good agreement with those tested by the four-point bending method. Thus, the method is applicable to the cantilever plates with l/b= 5 to 6, b/h = 4 to 10, and l/b = 4, b/h = 7 to 10 for cantilevered plates, etc.

Investigation on Strain Sensitivity and Temperature Behaviour of Nitrogen Doped 3C-SiC Thin Films

Electrical resistance-strain behaviour of nitrogen doped 3C-SiC thin films was investigated to determine whether they could be used as strain gauges. Using a hot wall vertical low pressure chemical vapour deposition (LPCVD) reactor, these films were deposited on thermally oxidised Si (100) and alumina substrates at 2.5 mbar pressure and 1040°C temperature from methyltrichlorosilane (MTS) precursor. The nitrogen doping gas utilised was ammonia (NH3). Using four-point bending method, the gauge factor (GF) was determined for all thin films (0, 9, 17, and 30 atomic % nitrogen doped). Systematic annealing of films in a vacuum atmosphere was used to determine the TCR of nitrogen doped 3C-SiC (111). Film sheet resistance was evaluated using a four-probe approach, and it was observed to decrease as the temperature rises from 40 to 550°C. The resistivity, average TCR, and strain sensitivity of film doped with 17 atomic % nitrogen concentration were 0.14 cm, -103 ppm/°C, and -9.6, respectively, indicating that it can be employed as a strain gauge material in high temperature applications. However, film doped with 30 atomic % of nitrogen concentration showed an increase in the resistivity, TCR and strain sensitivity.

Effects of the presence or absence and the position of glued edge joints in the lamina on the shear strength of glued laminated timber

Four kinds of glued laminated timber were produced (i.e., one with a glued edge-joint and the other three with nonglued edge joints) in the lamina at different positions toward the depth direction. Shear tests using an asymmetric four-point bending method were then conducted for these glued laminated timber specimens. The results showed that although the glued edge-joint specimens had the highest shear strength in all groups, the shear strength decreased as the distance from the adjacent nonglued edge-joint plane decreased. Furthermore, the shear strength of all specimens exceeded the standard shear design strength value (2.1 N/mm2) set by the Ministry of Land, Infrastructure, Transport and Tourism, Japan. Next, the shear strength of the nonglued edge-joint specimens was estimated based on that of the glued edge-joint specimens. Although the mean-estimated shear strength was lower than the mean-measured shear strength, the possibility of the shear strength changing based on the position of the nonglued edge-joint plane specimens from that of the glued edge-joint specimens was still estimated.

A Carbon Black/Polyvinyl Alcohol-Based Composite Thin Film Sensor Integrating Strain and Humidity Sensing Using the Droplet Deposition Method

Carbon black (CB) is a low-cost and excellent conductive material, and polyvinyl alcohol (PVA) is a non-conductive material with the advantages of easy processing and high mechanical stability. Here, we report a CB/PVA-based flexible conductive polymer film suitable for small strain detection and humidity detection. Thin film is formed by depositing the CB/PVA dispersion liquid droplets on a cleaned silicon/silicon dioxide (Si/SiO2) substrate. Theoretically, CB/PVA films can be transferred or formed on other substrates, such as polydimethylsiloxane, which have the advantage of flexibility. The droplet deposition method not only enhances the controllability of the film thickness and wastage of materials, but also improves the sensitivity of the prepared film. The electrical conductivity of the CB/PVA composite film and the relationship between the resistance change and strain were measured by the four-point bending method, which showed a good gauge factor of 30 when the strain rate was 0.007%. In addition, the sensor also showed excellent sensing performance and repeatability at humidity levels ranging from 10% to 70% RH. These results demonstrate that the CB/PVA thin film prepared in this work has the advantages of a simple fabrication process, low-cost, multifunctional properties, and high device sensitivity, providing further insights for detecting minor strain and humidity.

Hybrid Effect of Steel Bars and PAN Textile Reinforcement on Ductility of One-Way Slab Subjected to Bending.

Textile reinforced concrete (TRC) has gained attention from the construction industry due to several characteristics such as its lightweight, high tensile strength, design flexibility, corrosion resistance and remarkably long service life. Some structural applications that utilize TRC components include precast panels, structural repairs, waterproofing elements and façades. TRC is produced by incorporating textile fabrics into thin cementitious concrete panels. However, in order to use this strengthening method in construction practice, a design model is required. Investigating the combined effect of conventional steel and textile reinforcement on the ductility behavior of composite TRC/RC one-way slab is vitally important. Therefore, the current study describes the proper methods of calculating the ductility of the composite concrete reinforced by a direct combination of conventional steel and textile reinforcement. Four methods are presented to calculate the ductility of the three considered one-way slab specimens. The three slabs having dimensions 1500 mm × 500 mm × 50 mm were reinforced by steel bars (SRC), by steel with one layer of carbon fabric (SRC + 1T), and by steel with two layers of carbon fabric (SRC + 2T). The three slab specimens were cast by the hand lay-up method, removed from the molds, cured, and then tested in flexure after 28 days using the four-point bending method. The obtained results and calculations revealed the non-reasonability of using the conventional method based on yielding of steel reinforcement as the only criterion in the ductility determination. The results also confirmed the suitability of using the energy-based method over other discussed methods in the calculation of the ductility for the hybrid reinforced members.

In situ study on the effect of stress on corrosion behavior of AZ91 magnesium alloy

PurposeThis paper aims to investigate the corrosion evolution process of AZ91 magnesium alloy in 3.5 wt.% NaCl solution under different stresses by using in situ methods, thereby evaluate the influence of stress on the corrosion sensitivity of AZ91 magnesium alloy, and discuss the potential mechanism.Design/methodology/approachA four-point bending method was used to apply different loads to the magnesium alloy samples, a charge coupled device camera and electrochemical impedance spectroscopy test being used for in situ study. Scanning electron microscopy and X-ray diffraction (XRD) analysis were performed for corrosion product and morphology characteristics.FindingsThe observation results show that the corrosion of AZ91 magnesium alloy becomes more and more serious with the increase in the stress and generated many corrosion products. Originally, corrosion products prevented alloy matrix from contacting the corrosive medium. However, the increase in the stress facilitated the emergence of the corrosion holes in the corrosion products, which provided the microscopic channels for corrosive solution to attack the Mg alloy matrix, and accelerated the corrosion of the magnesium alloy, resulting in a lot of corrosion pits on the magnesium alloy surface under the corrosion product layer.Originality/valueThe evolution information of corrosion process is crucial to explore the mechanism of corrosion. Currently, most researches about corrosion of magnesium alloy used traditional testing techniques to obtain corrosion information, lacking the direct tracking and monitoring of the corrosion evolution process. Hence, this paper focuses on in situ corrosion study of AZ91 magnesium alloy. The technology with spatial resolution capability observed the changes in magnesium alloy surface at different times in the corrosion process in situ. Meanwhile, the in situ electrochemical technology was used to monitor the changes in micro-electrochemical signals during the corrosion process of magnesium alloy under different stresses.

MOMENT-CURVATURE ANALYSIS OF GRADED CONCRETE BEAM WITH CONCRETE STRENGTH DISPARITY VARIATIONS

The application of graded concrete on structural elements is predicted to increase the capacity of the structural performance, serviceability, and to reduce costs compared to conventional concrete structures. This study aims to analyze (1) the load-deflection relationship, (2) the moment-curvature, (3) the deflection ductility ratio, and (4) the crack pattern. This study used reinforced concrete (RC) beams specimens with the dimension of 13x19x150 cm which was categorized as reference specimens and graded concrete beams. For reference specimens, an RC beam possessing concrete strength of 30 MPa; 40 MPa; 50 MPa were prepared; For the graded concrete beams, two specimens made of 30-40 MPa; 30-50 MPa; 40-50 MPa were prepared. In terms of casting graded concrete beams, low-strength concrete is placed on the tensile fiber of the beam, while on the compressive fiber of the beam, high-strength concrete is placed. The specimens were tested using the four-point bending method. The results showed that the increase in the concrete strength in the compression fiber of the beam contributed to the increase in load capacity, stiffness, and serviceability in the post-crack phase. The increase of concrete strength in compression fibers by 20 MPa is considered effective and has a positive impact on the moment-curvature capacity and is considered efficient in construction costs. The deflection ductility of the beam is classified as partial ductile and is adequate for structural design in earthquake-prone areas. A flexural cracks pattern was found on each specimen.

Research on Dynamic and Static Test Methods for Evaluating the Poisson’s Ratio of Oriented Strand Board

In this article, dynamic method and static method of testing Poisson’s ratio of OSB (Oriented Strand Board) were proposed. Through modal and static numerical analyses, the position where the transverse stress is equal to zero was determined. The binary linear regression method was applied to express the gluing position of the strain gauge as a relational expression that depended on the length-width ratio and width-thickness ratio of the cantilever plate. Then the longitudinal and transverse Poisson’s ratios of OSB were measured by the given dynamic and static methods. In addition, the test results of OSB Poisson’s ratio were analyzed with the probability distribution of random variables. The results showed that using the proposed dynamic method and static method, the test results for longitudinal and transverse Poisson’s ratios of OSB were quite consistent, despite the gluing position of the strain gauges being different. And these OSB Poisson’s ratios were accorded with that obtained by the axial tensile method and the four-point bending method. OSB longitudinal and transverse Poisson’s ratios followed Weibull distribution.

Green synthesis of ITO nanoparticles using Carica papaya seed extract: impact of annealing temperature on microstructural and electrical properties of ITO thin films for sensor applications

ABSTRACT This paper reports the synthesis of indium tin oxide (ITO) nanoparticles and the effect of annealing temperature on the microstructural and electrical properties of ITO thin films. The synthesized ITO (90:10) nanoparticles are deposited at 29°C using E beam evaporation to form ITO thin films and annealed at 200, 400 and 500°C. The microstructural properties are investigated using XRD and AFM , and electrical properties such as temperature coefficient of resistance (TCR) and gauge factor are investigated using four-probe and four-point beam bending method, respectively. The investigations results reveal an increase in grain size, carrier concentration and gauge factor with an increase in the annealing temperature. The absolute value of TCR is constant at high temperatures for the film annealed at 500°C. The ITO thin film annealed at 500°C shows improved morphological and electrical properties and can be used for the development of sensors operating at high temperature.

The bending-shear behaviors of steel reinforced fast-growing poplar glulam beams with different shear-span ratios

A new type of steel reinforced fast-growing poplar glulam beam was proposed to improve the mechanical properties of fast-growing poplar glulam beam in this paper. 8 specimens were tested by a four-point bending method. The test was considered two factors: material properties (fast-growing poplar glulam beam, steel reinforced fast-growing poplar glulam beams) and shear-span ratios (1.5, 2, 2.5, 3, 3.5, 4, 6). Test results showed that: (1) The failure mode of the fast-growing poplar glulam beam was interlaminar shear failure. (2) When shear-span ratio (a/h) was between 3 and 6, the failure modes of the steel reinforced fast-growing poplar glulam beams were flexural failure; when shear-span ratio (a/h) was between 1.5 and 2.5, the failure modes of all steel reinforced fast-growing poplar glulam beams were interlaminar shear failure. (3) Compared with the fast-growing poplar glulam beam, the ductile coefficient, the ultimate load, the ultimate displacement and the initial bending stiffness of the steel reinforced fast-growing poplar glulam beams was increased by 92%, 34.7%, 64.7% and 60.9%, respectively. (4) With the increase of a/h, the ultimate load and the initial bending stiffness of the steel reinforced fast-growing poplar glulam beams decreased gradually, while the ultimate displacement and the ductile coefficient decreased first and then increased. Finally, the theoretical model is respectively proposed to estimate the flexural and shear capacity of the steel reinforced fast-growing poplar glulam beams.

Structural Performance of One-Way Slabs Reinforced with Steel and Polypropylene Fibers

The present study aims to investigate the effects of the steel fibers (SF) and polypropylene fibers (PPF) on the structural response of one-way simply supported reinforced concrete (RC) slabs at the ultimate limit state (ULS). Next, an optimized combination of the hybrid fibers is proposed. The experimental program includes 21 experiments on the one-way slabs with different SF and PPF ratios. The load-deflection curves were obtained for slabs using a four-point bending method. The ultimate capacity and mid-span deflection of the slabs were measured. The experimental results did not produce a consistent trend of ultimate loading. The different blends produced different failure modes, cracking load, and ultimate failure load. Based on the obtained test results, the slab specimen, SM6, with 0.7% SF and 0.9% PPF ratios has the maximum and the slab specimen, SM16, with 0.9% SF and 0.9% PPF ratios has the minimum load-carrying capacity, respectively. The first shows a 31% increase and the second indicates a 31% reduction when compared to the reference slab specimen, SM1, which has no fibers used in its concrete mixture. It is worth to mention that the slab specimen, SM6, which has the largest load-carrying capacity, also shows the highest ductility (172% enlargement in deflection when compared to the reference slab, SM1).