Showing papers on "Young's modulus published in 2022"

Effect of different burning degrees of sugarcane leaf ash on the properties of ultrahigh-strength concrete

Abstract: The global expansion of agricultural production increases agricultural waste ash (AWA). Accordingly, AWA should be disposed to preserve the environment. This study focuses on using AWA as a partial substitute for cement to produce ultrahigh-strength concrete (UHSC). This research investigated the effect of using sugarcane leaf ash (SLA) as a pozzolanic material on the properties of UHSC. The cement replacement rates by SLA were 10%, 20% and 30% by weight. SLA was heat-treated at 400, 500, 600, 700 and 800 °C for 2 h to improve its physical and chemical properties. The effects of the heat-treated SLA on UHSC mechanical properties such as, compressive strength, split tensile strength, flexural strength and modulus of elasticity, were studied. The effects of heat-treated SLA on UHSC durability such as, water permeability, chloride penetration and sorptivity of UHSC were also investigated. In addition to, microstructure analysis of several UHSC mixtures was presented. Results showed the efficiency of SLA as a partial substitute of the 20% of cement weight with mechanical properties and durability higher than the mechanical properties and durability of the reference mixture. Compared with the reference mixture, the heat-treated SLA used as a partial substitute generally improved all properties. The UHSC containing SLA heat-treated at 700 °C and a 20% substitution rate achieved the best results of 162.5, 17.78, 24.05 and 55,820 MPa for compressive strength, tensile strength, bending strength and modulus of elasticity at test age of 28 days.

Fiber-reinforced alkali-activated concrete: A review

Abstract: Alkali-activated materials (AAMs) received broad recognition from numerous researchers worldwide and may have potential applications in modern construction. The combined use of AAM and steel fibers are superior to typical binder systems because the matrix and fibers exhibit superior bond strength. The results obtained by various authors have shown that good dispersion of the fibers ensures good interaction between the fibers and the AAM matrix. The tensile strength of FR-AAC is superior to that of Ordinary Portland cement (OPC)-based materials, with the addition of silica fume (SF) being particularly remarkable. However, the tensile strength of fiber-reinforced alkali-activated concrete (FR-AAC) decreases with increasing fiber length. The bond strength increases with the increasing grade of concrete, the roughness of interface, and the solution's strength activated by alkalis. Regardless of fiber type, AAC's modulus of elasticity is linearly correlated with compressive strength. Fibers can affect the modulus of concrete due to the stiffness of the fiber and the porosity of the composite. Poisson's ratio for AAC corresponded to the ASTM C469-14 standard (about 0.22) and decreased to about 0.15–0.21 with silica fume addition. There are limited resources for the experimental Poisson's ratio and it is only estimated using the predictive equations available. Therefore, it is necessary to conduct additional experimental studies to estimate Poisson's ratios for FR-AAC composites. Retention of 59% and 44% in flexural strength during exposure at 800 °C and 1050 °C was observed in the FR-AAC stainless steel composite, and the chopped alumina fibers achieved higher yield strength at these temperatures. For FA-based AAC mortars with 1% SF with a hooked end, activated with a solution of NaOH and sodium silicate, an increase in the number of bends increased the bond strength, load pull-out and maximum pull-out strength. Autogenous shrinkage and drying shrinkage increase with higher silicate content, while shrinkage decreases with higher NaOH concentration. Relatively little research has been completed on FR-AAC in terms of durability or different environmental conditions. In addition, trends of development research toward the broad understanding regarding the application possibilities of FR-AAC as appropriate concrete materials for developing robust and green concrete composites for modern construction were extensively reviewed.

A Study on the Properties of Geopolymer Concrete Modified with Nano Graphene Oxide

Abstract: This paper reports the results of a study conducted to examine the impacts of adding graphene oxide (GO) to GBFS-fly ash-based geopolymer concrete. The geopolymer concrete’s compressive strength, thermal conductivity, and modulus of elasticity were assessed. X-ray diffraction (XRD) analysis was conducted to understand the differences in mineralogical composition and a rapid chloride penetration test (RCPT) to investigate the changes in the permeability of chloride ions imposed by GO addition. The results showed that adding 0.25 wt.% GO increases the modulus of elasticity and compressive strength of GBFS-FA concrete by 30.5% and 37.5%, respectively. In contrast, permeability to chloride ions was reduced by 35.3% relative to the GO-free counterparts. Thermal conductivity was decreased as GO dosage increased, with a maximum reduction of 33% being observed in FA65-G35 wt.% samples. Additionally, XRD showed the suitability of graphene oxide in geopolymer concrete. The present research demonstrates very promising features of GO-modified concrete that exhibit improved strength development and durability compared to traditional concrete, thus further advocating for the wider utilization of geopolymer concrete manufactured from industrial byproducts.

Drilling Data-Based Approach to Build a Continuous Static Elastic Moduli Profile Utilizing Artificial Intelligence Techniques

Abstract: Young's modulus is a principle geomechanical property that reflects the material stiffness. Good knowledge about rock mechanical properties significantly facilitates fracturing design and in-situ stresses estimation. Conventionally, rock elastic properties are estimated either experimentally or using well log data, known as static and dynamic respectively. Conducting experiments on core samples is costly, time-consuming and does not provide continuous information. While dynamic Young's modulus provides a complete profile, however, it needs the availability of acoustic logs and its estimations differ from the static values. The objective of this paper is to create a continuous profile of Young's modulus using the drilling rig sensors records. The presented approach relies on the fact that the drilling data such as drill pipe torque, weight on bit and rate of penetration are available at an early stage without additional cost. Three machine-learning algorithms were used to correlate the drilling data with Young's modulus: random forest, adaptive neuro-fuzzy inference system and functional network. Two different datasets were used in this study, one construct and test the model, while the other was hidden from the algorithms and used later to validate the built models. The two datasets contain over 3900 data points and cover different types of rocks. Two out of the three methods utilized yielded a remarkable match between the given and predicted values. The correlation coefficients ranged between 0.92 and 0.99 average absolute percentage errors were less than 13%. Supported by these results, the utilization of drilling data and artificial intelligence techniques to predict the elastic moduli is promising. This approach could be investigated for other geomechanical properties, besides, the performance of other machine-learning methods for the same purpose.

An investigation on mechanical properties of PA12 parts produced by a SLS 3D printer: An experimental approach

Abstract: Additive manufacturing methods such as Selective Laser Sintering (SLS) have attracted numerous scientists and different companies to print 3D parts. However, the mechanical properties of printed parts have been always the research area of many scientists. In this paper, the effects of SLS setting variables (laser power, scan speed, and hatch spacing) and scan length were investigated experimentally on key mechanical properties (strength, apparent modulus of elasticity, and elongation) of polyamide-12 printed parts using the response surface methodology. The results showed that the hatch spacing is the most effective variable on mechanical properties; the laser power and the scan speed are also important. By increasing the laser power and decreasing the hatch spacing and the scan speed, a higher strength part with a higher apparent modulus of elasticity and elongation can be printed. However, since a bigger hatch spacing and a faster scan speed are more desirable to have a more economical production, a challenging decision must be made for setting these variables to print parts with good mechanical behavior economically. If the hatch spacing, the laser power, and the scan speed are selected so that the laser energy density is too high, powders will burn and the printing process will fail. The scan length has a slight effect on the apparent modulus of elasticity and no significant effect on the strength and elongation. • Input variables: laser power, scan speed, hatch spacing, and scan length. • Mechanical properties: strength, modulus of elasticity, and elongation. • Effects of input variables on mechanical properties in the SLS process. • Determining effective inputs by experimental study and response surface methodology. • Predicting mechanical properties based on effective inputs and laser energy density.

Physical and Mechanical Properties of Particleboard Produced with Addition of Walnut (Juglans regia L.) Wood Residues

Abstract: The depletion of natural resources and increased demand for wood and wood-based materials have directed researchers and the industry towards alternative raw materials for composite manufacturing, such as agricultural waste and wood residues as substitutes of traditional wood. The potential of reusing walnut (Juglans regia L.) wood residues as an alternative raw material in particleboard manufacturing is investigated in this work. Three-layer particleboard was manufactured in the laboratory with a thickness of 16 mm, target density of 650 kg∙m-3 and three different levels (0%, 25% and 50%) of walnut wood particles, bonded with urea-formaldehyde (UF) resin. The physical properties (thickness swelling after 24 h) and mechanical properties (bending strength, modulus of elasticity and internal bond strength) were evaluated in accordance with the European standards. The effect of UF resin content and nominal applied pressure on the properties of the particleboard was also investigated. Markedly, the laboratory panels, manufactured with 50% walnut wood residues, exhibited flexural properties and internal bond strength, fulfilling the European standard requirements to particleboards used in load-bearing applications. However, none of the boards met the technical standard requirements for thickness swelling (24 h). Conclusively, walnut wood residues as a waste or by-product of the wood-processing industry can be efficiently utilized in the production of particleboard in terms of enhancing its mechanical properties.

Role of Fe2Al5 in fracture of novel dissimilar aluminum-steel resistance spot welds using multi-ring domed electrodes

Abstract: In a comparative study of resistance spot welded (RSW) 1.2 mm AA6022 joined to 2.0 mm high strength low alloy (HSLA) steel and 1.2 mm AA6022 joined to 2.0 mm low carbon steel (LCS) it was found that quasi-static tensile tests and mini shear tests exhibited similar intermetallic compound (IMC) strength but different load capacity, i.e., nominal shear strength in tensile shear tests. This phenomenon was related to the Fe2Al5 structure and properties at the Al-steel interface which were unique for each stack-up. The thicker Fe2Al5 layer in 1.2 mm AA6022-2.0 mm LCS was comprised of fewer but larger grains which contributed to a larger difference between the Young's modulus of FeAl3 and Fe2Al5 than in 1.2 mm AA6022-2.0 mm HSLA. The Fe2Al5 in the AA6022-LCS stack-up was more brittle and rigid with greater nanohardness values and smaller variation in elastic modulus that may have contributed to lower overall joint strength with large variation. In addition, AA6022-LCS welds produced with non-optimized and optimized weld schedules produced different IMC shear strengths which was attributed to the different mismatch in Young modulus values that accentuated the differences in shear stresses at the FeAl3/Fe2Al5 interface.

The behavior of sustainable self-compacting concrete reinforced with low-density waste Polyethylene fiber

Abstract: Sustainable concrete production and recycling the construction wastes are of utmost importance for today’s sustainable urban development. In this study, low-density polyethylene waste was recycled in the form of fibers (LDPF) to produce eco-friendly fiber-reinforced sustainable self-compacting concrete (SCC). The content of LDPF ranged from 0.5% to 3.5% at a raise of 0.5% of the mix’s volume. The SCC’s features in fresh and hardened states were tested. The slump flow diameter, T500, V-funnel, and L-box ratio were measured for the fresh properties. The compressive, splitting tensile and flexural strengths were tested at the age of 28 days. However, the outcomes indicated that LPDF had some negative effect on the workability features, but all the results of SCC mixtures were within the standard limitations of SCC except that related to the L-box, which satisfied the standards up to 2% of LDPF. However, the incorporation of LDPF enhanced the mechanical properties, especially the flexural strength. The optimum ratio for the LPDF was 2%, which satisfies the required workability and the highest strength with modulus of elasticity. The thermal conductivity decreased with increasing LDPF content in the SCC mixtures.

An investigation on the effect of curing conditions on the mechanical and microstructural properties of the geopolymer concrete

Abstract: Geopolymer concrete represents the future of green and sustainable concrete. It has a large impact on the construction industry owing to its better performance than that of conventional Portland cement concrete. This study aimed to identify the effect of curing conditions on the physical, mechanical, and microstructural properties of specimens using ambient curing and oven-curing. In the experimental analysis, we tested slump and setting time for physical properties, density and drying shrinkage for chemical properties, compressive strength, indirect tensile strength, modulus of rupture, Poisson’s ratio, and elastic modulus for mechanical properties, rebound strength, and UPVT for nondestructive and x-ray diffraction, and thermogravimetric analysis for microstructural analysis. After the experimental analysis, it was concluded that the density, Poisson’s ratio, and dry shrinkage were higher for ambient-cured specimens than for oven-cured specimens, whereas the compressive strength, indirect tensile strength, modulus of rupture, and elastic modulus of oven-cured specimens were higher than those of ambient-cured specimens. The nondestructive tests, rebound tests, and UPVT show that the oven-cured specimens are better in quality and strength than the ambient cured specimens. In microstructural analysis, x-ray diffraction showed that the oven-cured specimens had a lower intensity of mineral oxides than the ambient-cured specimens in microstructural analysis. The matrix of the ambient-cured specimens was thermally stable up to 800 °C and retained 92% of its original mass, whereas the matrix of the oven-cured specimens retained 94% of its mass up to 800 °C in the thermogravimetric analysis.

Furfurylation Effects on Discoloration and Physical-Mechanical Properties of Wood from Tropical Plantation Forests

Abstract: Wood from tropical plantation forests has lower physical and mechanical properties than mature wood. Furfuryl alcohol (FA) impregnation into the wood could help to enhance hydrophobic properties, dimensional stability, and structural strength. Furfurylation was applied to specimens of the following four fast-growing tropical wood species: jabon (Anthocephalus cadamba), sengon (Falcataria moluccana), mangium (Acacia mangium), and pine (Pinus merkusii). The discoloration and physical and mechanical properties were subsequently measured, and the results showed that furfurylated wood had a darker color and better physical and mechanical properties than untreated wood. Specifically, the furfurylated wood had higher density, modulus of elasticity, and hardness and lower moisture content, water absorption, swelling, and shrinkage. The furfurylation significantly enhanced physical and mechanical properties.

Expansion of Takayanagi model by interphase characteristics and filler size to approximate the tensile modulus of halloysite-nanotube-filled system

Abstract: Existing models are unacceptable for the modulus of nanocomposites, because they disregard the interphase section. In the present work, the interphase features (depth and modulus) and halloysite nanotube (HNT) size (radius and length) are added to Takayanagi model to obtain an advanced model for the modulus of HNT-based system. The accuracy of advanced model is examined by the experimented values of modulus for numerous examples and by the clarifying of the impacts of all factors on the modulus of system. The tested facts of modulus for various types of examples certify the approximations of the advanced model. The absence of interphase section improves the nanocomposite's modulus by 8.2%, but the modulus of samples raises by 16.2% at the interphase depth of 20 nm. The interphase modulus of 10 GPa increases the nanocomposite's modulus by 10.5%, while the modulus of system promotes by 12.6% at interphase modulus of 60 GPa. Additionally, HNT radius of 20 nm enhances the modulus of system by 14.5%, but HNT radius of 60 nm negligibly grows the modulus of samples by 9.7%. Accordingly, the deepness and modulus of interphase section straightly control the modulus of system, while HNT radius plays an opposite role in the stiffening.

Experimental Testing on Mechanical, Durability, and Adsorption Dispersion Properties of Concrete with Multiwalled Carbon Nanotubes and Silica Fumes

Abstract: The major goal of this research is to see how carbon nanotubes and silica fume affect the durability and mechanical qualities of high-performance concrete (HPC). Mechanical properties, such as split tensile strength, compressive strength, elasticity modulus, and flexural strength, and durability properties like water absorption, abrasion, chloride penetration, acid, and sea water resistance, impact resistance of HPC consisting silica fume (SF), and carbon nanotubes (CNT) were examined in this study. Varied trail combinations with different proportions of CNT and SF admixtures were created for this reason. Portland cement was partially replaced with 1 percent, 1.5 percent, 2 percent, and 3 percent CNT, while SF was substituted with 5 percent, 7.5 percent, and 10 percent. Both CNT and SF outperform conventional concrete in terms of mechanical and durability attributes, according to the findings. CNT produces superior results than SF due to its smaller size.

The Application of Various Bark Species as a Fillers for UF Resin in Plywood Manufacturing

Abstract: The aim of the presented study was to apply various bark species (birch, beech, maple, pine and spruce) as fillers for urea-formaldehyde (UF) resin in three-layer plywood manufacturing. For this purpose, all types of bark were ground and added to the adhesive mixture. The resultant plywood was subjected to investigations of the following: tensile strength, modulus of elasticity (MOE), bending strength (MOR) and formaldehyde emission. The results indicate a reduction in the tensile strength. Moreover, the lack of significant improvement in strength parameters can be explained by too high a load of the filler (20 wt%). In the case of formaldehyde emissions, a reduction was observed for birch (B-1), beech (B-2), maple (B-3) and pine bark (B-4). In addition, an increase in the emission of formaldehyde was recorded only for spruce bark.

Analysis of Measured Parameters in Relation to the Amount of Fibre in Lightweight Red Ceramic Waste Aggregate Concrete

Abstract: The present study provides a correlation and regression analysis of lightweight waste aggregate concretes with varying degrees of fibre reinforcement. The concrete mix contains pre-soaked red ceramic waste aggregate, expanded clay coarse aggregate and Portland cement. Copper-coated crimped steel fibre was used as the reinforcement. The experimental results included properties measured by destructive test methods—compressive strength, splitting tensile strength, static modulus of elasticity, the limit of proportionality, shear strength; and by non-destructive test methods—dynamic modulus of elasticity and surface electrical resistivity. These properties were analysed to study the relevancy and significance between non-destructive and destructive methods of measurement in the case of different amounts of fibre. The results show differences in the degree of fit to the linear and quadratic regression curves for pairs of destructive and non-destructive test results. As expected, the linear relationship can be applied in a few cases, but the quadratic curve must be used for a few pairs. Another observation is that it is not possible to neglect the amount of fibre in the correlation analyses of the measured properties.