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Efforts have been dedicated to developing sustainable alternatives for conventional construction materials, resulting in the development of densified wood as an innovative, environmentally friendly, and high-performance material. This study focuses on investigating the effects of treatment parameters (e.g., partial delignification boiling time, chemical concentrations, and hot-pressing pressures) on the chemical, morphological, and mechanical properties of the densified wood. Results revealed that the partial delignification process of low-density Balsa wood reduced lignin content by 50–80%, which enhanced the crystallinity of the wood by 21–54%. However, prolonged periods of partial delignification caused a degradation in the crystalline regions in wood. The modulus of rupture (MOR) and modulus of elasticity (MOE) of the densified wood samples increased by 90–680% and 10–810% compared with those of the raw wood samples, respectively. The MOR of the densified wood also showed a dependency on lignin content and porosity. An optimal lignin content of approximately 10% was associated with the highest MOR in densified wood. Moreover, the relationship between the MOR and porosity suggested that the MOR improvement occurred in two stages. The first stage of MOR improvement is controlled by the reduction in the porosity and the second stage is controlled by the improved hydrogen bonding among cellulose nanofibrils. • Partial delignification reduced lignin content and enhanced crystallinity of wood. • Strength was largely improved through chemical treatment and hot pressing. • Prolonged boiling treatment degrades wood crystalline structure. • Porosity reduction and enhanced nanofibril bonding control strength of treated wood. [ABSTRACT FROM AUTHOR]

In this study, a method known as pre-wetting is applied between the multilayer ceramic investment casting shells to enhance porosity and permeability while sustaining flexural strength. Pre-wetting consists predominately of an aqueous silica binder that improves inter-coat bonding in complex areas. Porosity is developed where the pre-wetting is applied due to the evaporation of the aqueous phase. Results indicate that as porosity increases, both green and fired flexural strength reduce on average by 8.7 - 15.6 % and 18.7 - 28.5 %, respectively, whereas hot strength is increased by 20 - 25 %. Permeability increased by a factor of two when pre-wetting was applied between intermediate coatings and displayed a stepwise increase in intrusion volume in the high-pressure regime through mercury intrusion porosimetry. X-ray microtomography coupled with pore network modelling provided a validation of the increase in the permeability constant. Gas adsorption methods revealed the presence of micropores through the alpha-s method when bilayers of pre-wetting solution were applied. [ABSTRACT FROM AUTHOR]

Standard ceramic tiles doped with powdered, micro-sized lead oxide (PbO) were manufactured with weight fractions (2.5%, 5%, 7.5% and 10%) and investigated for γ-ray shielding ability. Several methods were used to characterize the newly fabricated ceramic samples. These included Fourier transform infrared spectrophotometer (FT-IR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), energy dispersive X-ray (EDX), scanning electron microscope (SEM) and high-resolution transmission electron microscope (HR-TEM). The mechanical properties of assembled ceramic composites were examined and their modulus of rupture (MOR) was calculated. Results revealed that the values of MOR varied between 1.884 and 2.158 MPa, as the content of PbO increased from 0.0 to 10.0 wt% in the ceramic body. Physical properties, such as density and percentage of water adsorption, were determined. To evaluate γ-ray attenuation coefficients (μ m) of the investigated samples, different energies in the range of 59.53–1332.50 keV were applied and a NaI detector was used to measure photon intensities, as a function of the weight percentage of PbO. Confirmation of the accuracy of these results was performed, when a comparison was made with the theoretical values obtained from the XCOM simulation code. Two more parameters were tested to ensure the shielding capabilities of the new composites, namely the half value layer (HVL) and the mean free path (MFP). These values were calculated to reveal that the ceramic composite containing 10 wt% PbO exhibited the highest μ m and lowest MFP and HVL values of all other tested composites. The outlined results confirm the significant improvement in γ-ray shielding properties of ceramic tiles as the wt% of PbO increased from 0.0 to 10.0 wt%. [ABSTRACT FROM AUTHOR]

Glubam is a type of engineered bamboo, which can be used as structural members in buildings. To explore the potentials of glubam for various application environment, this study examines the bending performance of three types of glubams at conditions of low temperature (−196 ℃～20 ℃) and freeze-thaw cycle. A total of 260 specimens were tested under static bending at different temperatures, in order to provide the reference data for the low-temperature design of the bamboo structure. The elastic modulus (MOE) and modulus of rupture (MOR) of three types of glubams under the condition of oven-dried and air-dried were measured respectively through static bending tests. The morphological characteristics after low-temperature treatment were explored by optical microscope and scanning electron microscopy (SEM). The results showed that thin-strip glubam, thick-strip glubam and side-pressed glubam all show good bending performance at −50 ℃. The oven-dried glubam showed a different variation trend from air-dried glubam and the strength variation amplitude of oven-dried glubam is smaller than that of air-dried glubam. Glubam at conditions of low temperature and freeze-thaw cycle showed the same variation trend. However, the effects of freeze-thaw cycle on MOR and MOE were not significant. This pilot research provides basic performance data for potential applications of engineered bamboo in low temperature situations, such as buildings and facilities in polar regions as well as extremely low temperature situations such as high altitude. • The three types of glued laminated bamboo (glubam) all showed good bending performance at −50 ℃. • The strength variation amplitude of oven-dried glubam is smaller. • The effects of freeze-thaw cycle on MOR and MOE were not significant. [ABSTRACT FROM AUTHOR]

• The possibility of using pulp log from fiber managed eucalyptus in CLT was assisted. • Flexural performance of CLT panels from E. globulus is higher than that of E. nitens. • Flexural performance of the panels is higher than that of other eucalyptus species. • Failure mode is affected by the grades of top and bottom layers board. This study was performed to evaluate the flexural performance of three-ply cross-laminated timber (CLT) floor panels made of unthinned and unpruned plantation Eucalyptus. The impact of the stress-grade of the timber boards on the modulus of elasticity (MOE) and modulus of rupture (MOR) of the panels was determined. The results indicated that the actual MOE of the timber boards from both species could not be appropriately estimated by visual stress-grading. The results revealed that the average MOE and MOR of the panels were significantly affected by the stress-grade of the boards in the top and bottom layers of the panels. The CLT panels made with high-grade boards showed respectively 24% and 21% higher MOE values than comparable panels made with low-grade boards for E. nitens and E. globulus. The failure modes were bending failure on the tensile side and rolling shear for the panels made of low-grade and high-grade boards, respectively. On average, the CLT panels made of E. globulus showed 17.7% higher MOE and 32.5% higher MOR values than comparable panels made of E. nitens. [ABSTRACT FROM AUTHOR]

Abstract The plasticity of thermally modified European oak (Quercus robur L.) and f thermally modified Norway spruce (Picea abies Karst. (L.)) timber was evaluated in bending, and the plastic properties were related to the changes in chemical composition of the wood after modification. The objective was to gain new knowledge about the properties of materials in the plastic region of the force-deformation diagram in bending. A new software was developed (MATESS) and used to identify important characteristics of the material. This software eliminates shortcomings in current standards, such as simplifications in the evaluation of data when sufficiently sensitive measuring equipment is not available. The characteristics studied were: modulus of rupture (MOR), plastic potential (P P) chord modulus (CH M), the moduli of plasticity (E E), and the moduli of plasticity (E MV , E P). Extractives, lignin, cellulose, holocellulose, and hemicelluloses were analysed chemically to reveal the patterns that occur during the loading of the specimens. Thermal modification has different effects on the mechanical properties of oak and spruce, especially on CH M , E MV and E P , due to their different contents and structures of their chemical components. A strong correlation (r > 0.90) between hemicellulose content and MOR and Pp values was found for both species. The coefficients of determination indicated a very low dependence (r2 < 0.1) of MOR, P P , CH M , E E , E MV and E P , on the average density. Highlights • Impact different temperatures be the termal modifications on the selected properties in plastic area. • On basic the results we can modified technology of thermally modifications in wooden constructions. • The methods of modification (thermal treatment) can be modified in order to achieve the required material parameters. • Thermal modification has a different effect on the mechanical properties of oak and spruce (especially CHM, EMV and EP). • However, there were strong correlations (r > 0.90) between changes in hemicelluloses and MOR and Pp values in both species. • In the correlation between the MOR, PP, CHM, EE, EMV EP and the average density, the coefficients of determination were very low (r2 < 10%). [ABSTRACT FROM AUTHOR]

Highlights • Replacing a part of normal aggregate with PVC aggregate has low effect on the physical properties of concrete. • Workability of concrete is reduced at high PVC content. • Elastic modulus of concrete are appreciably deteriorated with increasing PVC aggregate. • There is a chance to use 30% of PVC aggregate in concrete. • Abrasion resistance is enhanced well as part of natural aggregate is replaced with PVC aggregate. Abstract This paper describes experimental tests on concrete made of coarse aggregate or fine aggregate partially replaced with plastic waste derived from PVC waste sheets. The main goal behind this experiment is the inspection of important properties of concrete affected by the plastic waste addition, for the purpose of consuming the waste and production of an eco-friendly concrete. Results indicate that there is a chance to replace fine or coarse aggregate with PVC aggregate not more than 30% for the production of concrete with acceptable properties. At this plastic content there is a margin loss of workability, absorption, and different strengths. Compressive and splitting tensile strengths loss was found not more than 8%. Elastic modulus of concrete is highly affected by the existence of PVC aggregate, especially when coarse aggregate is replaced. Abrasion resistance of concrete can be increased well as PVC aggregate is used instead of the natural one especially coarse aggregate. [ABSTRACT FROM AUTHOR]

Highlights • The influence of drilling size on the bending properties of bamboo scrimber. • The influence of drilling position on the bending properties of bamboo scrimber. • The failure modes of the bamboo scrimber with holes in different size and position. Abstract To the requirements of introducing holes for the structural applications of bamboo scrimber, the bending properties of bamboo scrimber, which used Moso bamboo as the raw material, with holes in different sizes at different positions were studied and compared. The results indicated that drilling holes cause the decrease of the bending properties and the larger size for drilling holes causes the lower bending properties. The positions for drilling holes cause the change of the stress distribution and then decrease the bending properties. According to the comparisons of different bamboo tested samples, two basic failure modes were proposed, one is the split along the direction of bamboo fibers around the holes caused by shear stress, and the other is the fracture at the bottom of the tested samples by bending stress. [ABSTRACT FROM AUTHOR]

Highlights • Scoria and pumice enhance concrete resistance to heat-induced strength degradation. • Scoria and pumice preserve concrete performance pointers at reduced cement amount. • Scoria and pumice modify concrete microstructure thereby lowering permeability. Abstract Cement industries have a huge CO 2 signature that can be reduced in an effort to mitigate climate change via precise cement substitution with supplementary cementing materials (SCMs). The substituting materials and their amounts ought not to degrade the key performance indicators of concrete such as slump, flow, permeability, shrinkage, modulus of rupture, compressive, and tensile splitting strength. In this study, the influence of natural scoria (SN) and pumice (PN) binders on the key performance indicators of the fresh and hardened Portland cement (PLC) concrete was successfully examined. The performance indicators were tested at PLC substitution (with SN or PN) levels of 10, 20, 30, and 40% and the results compared to the control (CTRL) made of PLC only. The results show that 10% is the optimum substitution level for both SN and PN. The compressive strength, modulus of rupture, shrinkage, permeability, and thermal stability of the concrete were not compromised at this substitution level. The 28 days modulus of rupture, shrinkage, and compressive strength for SN and PN at 10% substitution were 6.0 and 6.4 MPa; 0.02 and 0.01 mm; 44.2 and 43.1 MPa, respectively. These compared remarkably well with 6.3 MPa modulus of rupture, 0.01 mm shrinkage, and 43.1 MPa compressive strength of the control. Moreover, SN and PN delivered higher % residual compressive strength of 59.2 and 57.8%, correspondingly, after subjecting the concrete to high temperatures of 600 °C, compared to 52.6% for the control. Likewise, the coefficient of permeability (K) for SN (5.2526E−08 m/s) was similar to that of PLC (5.35714E−08 m/s). At substitution levels higher than 10%, more than one key performance indicators were negatively affected. These results show the utility of SN and PN in reducing the amount of cement used in construction and thus the CO 2 emission associated with cement industries while at the same time preserving the strength, permeability, thermal and volume stability and hence the durability of the concrete. [ABSTRACT FROM AUTHOR]

Particleboard is one of the wood-based composite products, developed from wood and wood industry waste in admixture with an adhesive by thermos-compression. Wood is gradually becoming scarce due to deforestation and it leads to search for an alternative raw material. Jute, flax, and hemp plants are important fibre yielding industrial crops since their respective farming provides economic support to the developing nations from the rural areas. After the extraction of fibres from them, a lot of biomasses in terms of shives and sticks are generated as agricultural waste, and recently, these lignocellulosic biomasses have attained a special attention for the development of medium density particleboard. In this present work, an attempt has made to study the effect of flax shive and jute stick particle blends in admixture with phenol formaldehyde resin on the performance of the particleboard in terms of density, modulus of rupture and water swelling. The particle size distribution, bulk density, chemical composition, thermal properties, and surface chemistry of jute stick and flax shive have studied to assess their compatibility. Results inferred that a 50% jute stick: 50% flax shive combination based particleboard met the desirable properties of a medium density particleboard and showed higher performance than other combinations. It could be concluding that the combined use of biomass residuals for the development of a potential industrial product like packaging box, furniture, false ceilings etc, and it could open a new avenue to their farmers for the creation of wealth from the waste. • Flax shive is compatible with Jute stick to form a medium density particle board. • Flax shive influences the mechanical properties of the particleboard through good physical interlocking. • 50% jute stick and 50% flax blending has significant effect on mechanical properties of particleboard. [ABSTRACT FROM AUTHOR]

Sugar Cane Bagasse Ash (SCBA) is an advanced cementitious material contains significant amount of pozzolanic minerals like silica, alumina, etc. In view of this, in the present study it is proposed to partial replacement of Ordinary Portland Cement (OPC) by SCBA up-to 30%. OPC was replaced in two forms, namely, Original SCBA (O-SCBA) and Processed SCBA (P-SCBA). The mechanical properties such as cylinder compressive strength, Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) were evaluated for SCBA blended concrete and compared with conventional concrete. Further the relationships between cylinder compressive strength, MOR and MOE were established as per AS3600 (Australian Standards 3600), ACI318 (American Concrete Institute 318) and NZS3101 (New Zealand Standard 3101). [ABSTRACT FROM AUTHOR]

Geopolymer-mullite composite was prepared using fly ash and mullite powders with sodium silicate and sodium hydroxide as alkaline activators. Mullite was used as a replacement to fly ash in the 20–60 wt% range. Sodium silicate to sodium hydroxide (12 M) ratio was 1:1 while the liquid to solid ratio was 0.6:1. X-ray diffraction (XRD) analysis revealed that the set of geopolymer specimens without mullite replacement (control) showed the co-existence of amorphous and crystalline phases of quartz, magnesioferrite (Fe 2 MgO 4 ), Lazurite (Na 8.56 (Al 6 Si 6 O 24 ) (SO 4 ) 1.56 S 0.44 )) and calcium silicate hydrate. With an increasing amount of mullite replacement, calcium silicate hydrate and magnesioferrite diminished while the new phase of phillipsite (K, Na) 2 (Si,Al) 8 O 16 ·4H 2 O) emerged. Microstructural analysis revealed Si-rich mullite needles possibly occurred by recrystallization of the original mullite. This suggestion was also confirmed by the change of the crystallite size as analysed using an X-ray diffraction technique. The ambient compressive strength was found to increase from 58 ± 21 MPa for the control geopolymer to 72–76 MPa, with a much smaller uncertainty, for the geopolymer-mullite composite. Modulus of rupture (MOR) was found to improve significantly from 0.7 ± 0.3 MPa to 3.7 ± 0.5 MPa in the 20% replacement and further to 7.8 ± 1.3 and 8.1 ± 1.1 MPa in the 40% and 60% replacement respectively. Improvement of fire resistance was observed in the 40–60% replacement thermal shock resistance property, however, was unchanged in these geopolymer-mullite composite. [ABSTRACT FROM AUTHOR]

This study aims to investigate the age-dependent changes in flexural and fracture properties of fiber-reinforced concrete (FRC) used in the design of thin overlay pavements. Total four different types of steel or polypropylene macro-fibers with different dimensions and different fiber volume contents (0%, 0.5%, and 1.0%) were selected and investigated. No significant changes in compressive strength, free drying shrinkage, coefficient of thermal expansion, and modulus of rupture versus age were identified. Steel FRCs were observed to have a constant or increased residual strength as a function of age while different types or contents of polypropylene FRCs showed varied trends in residual strength versus age. Fracture energy for all FRCs was observed to increase versus age. Residual strength ratio for all FRCs decreased as a function of age, but with only two replicates per age and FRC type, values were highly variable so no trends were statistically verified at this time. A standard test age is recommended due to the changing residual strength ratio parameter used in thin FRC overlay design. [ABSTRACT FROM AUTHOR]

• This study proposes using Grey Wolf Optimizer (GWO) combined with Artificial Neural Network (ANN) to calculate MOR and MOE. • Using a database of 104 samples from Spruce and Larix wood previously published experiments. • Developing a Particle Swarm Optimization (PSO) Algorithm trained ANN to determine MOR and MOE. • Using Multiple Linear Regression (MLR) and Nonlinear Regression (NLR) models for the determination of MOR and MOE. • The accuracy of the best-performed model of GWO-ANN was evaluated with different models, and the GWO-ANN model has higher accuracy than the PSO-ANN, MLR, and NLR models. The study investigates the Modulus of Rupture (MOR) and Modulus of Elasticity (MOE) of the heat-treated wood by implementing Artificial Neural Networks (ANNs) on a dataset of 104 Spruce and Larix wood species obtained from literatures. The Feed Forward (FF) networks with various topologies were employed considering heat treatment at varying temperatures, times, and relative humidity (RH) as input parameters. The Grey Wolf Optimizer (GWO) was used to optimize the weight of the networks by reducing the error. The accuracy of the proposed ANN model (GWO-ANN) was obtained by comparing the results of performance indicators obtained by Particle Swarm Optimization (PSO), Multiple Linear Regression (MLR) and Nonlinear Regression (NLR) models. The results concluded higher accuracy of GWO-ANN model with a coefficient of correlation, R2, equals 0.975 and 0.960 and the Average Absolute Error (AAE), equals 0.01 and 0.01 for the MOR and MOE, respectively. [ABSTRACT FROM AUTHOR]

The deflection and cracking behavior of concrete structure depend on the flexural tensile strength of concrete. Many factors have been shown to influence the flexural tensile strength of concrete, particularly the level of stress, size, age and confinement to concrete flexure member, etc. The concrete members, in general, are of large continuous size and have at least minimum reinforcement introducing a confining effect to the concrete. The confining reinforcement increases ductility and large deflections in structures provide a good warning of failure prior to complete failure of the flexure member and also for efficient use of constructional material, it is desirable to take full advantage of long-term strength gain. Therefore, the effect of the factors like level of stress, age and confinement of concrete member should be given prime importance while studying the flexure tensile strength of concrete. This paper presents an experimental study done to predict the flexural tensile strength considering the confinement conditions and age of concrete for a wide range of concrete strengths (from 30 to 85 MPa). It is concluded that the factors like confinement conditions and age of concrete should be given due consideration in deriving the flexural tensile strength and compressive strength proportionality equations. [ABSTRACT FROM AUTHOR]

In this work, a novel composition of self-flowing, ultra-low cement (ULCC) tabular alumina-based castables is developed. Ultra low cement castables (ULCC) are processed using various amounts (5, 3, 1, 0.1 and 0.01 wt%) of nano-ZrO 2 and yttria-stabilized zirconia, (YSZ) and then sintered at different temperatures up to 1773 K. In addition, binding systems without aggregates with varying yttria contents (1, 2, 3 and 8 mol%) and stabilized ZrO 2 are sintered at 1273 K, 1573 K and 1773 K for 3 h. In order to disclose the effect of nano-ZrO 2 additions, firing temperatures, and corresponding phases, present in the castables are investigated using dynamic light spectroscopy (DLS), X-ray diffraction, scanning electron microscopy (SEM), fracture toughness, and three point bending (MOR). DLS results show that the nano-ZrO 2 particles are effectively distributed in the matrix using either additives or ultrasonification. It is found that the addition of 3 wt% nano-ZrO 2 improves the MOR of self-flowing castables (SFCs) by 20% and 50% matrix and binding systems respectively due to stabilization of t-ZrO 2 . Alternatively, there is no noticeable change in the exhibited K IC of castables when aggregates are present. In contrast, the K IC of aggregate-free binding systems can reach values of up to 2.27±0.21 MPa m 1/2 with the addition of 1 wt% Y-ZrO 2 . The experimental outcome indicates that the presence of alumina aggregates in the SFCs leads to excessive porosity and inherent flaws in the binding regions when the refractories are fired at high temperatures. Consequently, the effect of nano-YSZ in promoting toughness is significantly reduced or eliminated due to the presence of high porosity and internal flaws in the SFCs. [ABSTRACT FROM AUTHOR]

• Taguchi analysis has been used to determine optimum mix design parapeter of RPC exposed to different Na 2 SO 4 solutions and exposure conditions. • Optimized level for RPC mixture with different water to binder ratio, steel fiber contents, and silica fume contents depends on different external sulfate attack exposure conditions. • RPC appears to be sustainable and durable material under different external sulfate attack exposure conditions. Reactive powder concrete (RPC) is defined as a cementitious composite material with an optimized size of granular constituents, very low water-to-binder ratio (w/b), pozzolanic materials like silica fume (SF), and discontinuous fiber reinforcement. RPC applications include bridge decks and girders, seismic columns, wind turbine towers, and pile foundations. Especially, a durable and robust RPC pile foundation with long service life is essential in building construction because continuous maintenance is impossible. Moreover, natural in-situ conditions such as water table, temperature, and sulfate concentration in soil to which the pile foundation is exposed are critical and related to deteriorating the pile foundation. Therefore, the Taguchi design of experiments (DOE) was used in this research to determine the optimal RPC mixture with beneficial characteristics against external sulfate attack (ESA). Mixture design parameters included steel fiber content (0, 1 and 2 %), w/b (0.16, 20 and 0.24), and SF content (15, 20 and 25 %). In contrast, environmental conditions of ESA exposure contained three different sodium sulfate (Na 2 SO 4) concentrations (0.35, 1.05, and 3.15 M), cyclic and continuous exposure at normal temperature (20 °C), and continuous exposure at elevated temperatures (40 °C and 60 °C). The analytical and statistical investigation evaluated mass change, compressive strength, and modulus of rupture in RPC mixtures exposed to these conditions for 52 weeks. Test results show that cyclic exposure and increased solution temperature in ESA facilitate RPC damage. If measured after air drying, RPC mixtures subjected to cyclic ESA are especially susceptible to failure. Taguchi analysis indicated the optimum parameters' level for mass change as: 0 % steel fiber, w/b = 0.16, and 20 % SF content; for the compressive strength: 2 % steel fiber, w/b = 0.24, and 20 % SF content; and, for modulus of rupture: 2 % steel fiber, w/b = 0.20, and 25 % SF content. In conclusion, RPC appears to be sustainable and durable material under different ESA exposure conditions. [ABSTRACT FROM AUTHOR]

The main objective of the study presented in this paper was to examine the effect of key factors, which affect the performance of reactive powder concrete (RPC) mixtures. Firstly, an optimum sand grading was selected based on the maximum compressive strength and acceptable flow of a typical RPC mixture keeping the proportions of its ingredients constant. Then, keeping the sand grading and fiber content constant at their optimum levels, a total of 27 mixtures of RPC were selected for study by considering three levels of the three key factors namely water-to-binder ratio, cement content and silica fume content, according to a 3 3 factorial experiment design. The dosage of superplasticizer for each mixture was optimized to keep the flow in the desirable range of 180–220 mm. The performance of the selected mixtures of RPC was evaluated in terms of compressive strength, modulus of rupture and modulus of elasticity. Statistical analysis of the experimental data indicated the significant effect of sand grading, water-to-binder ratio, cement content and silica fume content on flowability and mechanical properties of RPC. The regression equations were obtained for mechanical properties of RPC mixtures in terms of the key mixture parameters, which can be utilized to optimize the proportions of RPC mixtures within the ranges of the mixture variables considered in this study. [ABSTRACT FROM AUTHOR]

The effect of low temperatures (< 0 °C) on the mechanical properties of wood materials was investigated in this study. The modulus of rupture (MOR) and modulus of elasticity (MOE) of birch ( Betula platyphylla ) with five different levels of moisture content (MC) (water-saturated, green, fiber-saturated, air-dried and oven-dried), were analyzed for temperature from 0 °C to − 196 °C. The morphological characteristics at low temperatures were explored by means of the cryogenic scanning electron microscopy (Cryo-SEM). The results showed that when the temperature was below 0 °C, MOR and MOE of specimens increased with decreasing temperature. Significant differences ( p < 0.05) in MOR and MOE of the specimens at four out of five MC levels (water-saturated, green, fiber-saturated, and air-dried) were observed between + 20 °C and − 196 °C. However, the effects of low temperatures on MOR and MOE of the oven-dried wood specimens were not significant. The higher the MC, the greater and faster was the increase in MOR and MOE. The ductility ratio decreased with decreasing temperature for all MC levels, which means increasing flexibility below 0 °C. The findings suggest that extremely low temperatures have an important influence on the performance of wood with various MC. [ABSTRACT FROM AUTHOR]

Construction and Demolition (C&D) wastes are increasingly used as construction material in a range of civil engineering applications. Fine Recycled Glass (FRG) is collected at municipal kerbsides and its usage to date has been limited to unbound pavement layers. This research was undertaken to evaluate the performance of FRG as a supplementary material in blends with cement stabilized recycled concrete aggregate (RCA). Laboratory evaluation was undertaken on the RCA/FRG blends with 10%, 20% and 30% FRG content and stabilized with 3% medium setting General Blend (GB) cement. The laboratory evaluation was comprised of pH, plasticity index, foreign materials content, particle size distribution, linear shrinkage, California Bearing Ratio, modified Proctor compaction, Repeated Load Triaxial test, Unconfined Compressive Strength test and flexural beam tests. The cement stabilized RCA/FRG blends with up to 30% FRG content were found to have physical properties, which comply with the local state road authority requirements. The results of Repeated Load Triaxial tests indicated the RCA/FRG blends performed well with 30% FRG content just on the border line for bound pavement material. Unconfined Compression Strengths met the minimum requirement for 7 days of curing for all blends, while the 28 day strength of the blends showed a significant improvement with curing. The results of the flexural beam tests were noted to be consistent with past works with cement stabilized virgin quarry rock products. The modulus of rupture and flexural modulus for all the cement-stabilized RCA/FRG blends indicate that these blends are suitable for applications such as cement-stabilized pavement bases/subbases. The fatigue life was also within the range previously reported for quarry materials. The cement-stabilized blends with FRG as a supplementary material with up to 30% FRG content and 3% GB cement were found to have physical and strength properties, which would comply with road authority requirements. [ABSTRACT FROM AUTHOR]

The present paper discusses the possibility of adding recycled polymer fibres to high performance concrete (HPC). Fibres used in this study were recovered from discarded car timing belts. To investigate different characteristics of the concrete specimens several destructive and non-destructive tests, such as compressive strength, modulus of rupture, flexural toughness, ultrasonic velocity and electrical resistance tests were carried out. In addition, slump flow tests were conducted on the fresh concrete. Experimental results from the study showed that the use of low percentages (up to 0.5%) of waste fibres improved the modulus of rupture and flexural toughness. Based on ultrasonic and electrical resistance test results, an increase in fibre percentage also increased the pore volume and electrical resistance of the fibre reinforced concretes with respect to a control mixture. [ABSTRACT FROM AUTHOR]

The TiB 2 -based Fe–matrix cermets with titanium addition (literarily different Ti:B ratio) were fabricated from elemental powders “in situ” using the Self-propagating High-temperature Synthesis method (SHS) under high pressure. The effect of Ti:B ratio on microstructure and phase composition with particular focus on matrix phase were analyzed using X-ray diffraction (XRD) and Wavelength Dispersive Spectroscopy (WDS) for composites with intended 25 vol.% and 35 vol.% of Fe. Moreover, for composites with 35 vol.% of Fe bending strength and compressive strength were investigated. The compressive strength reached maximum value in material with Ti:B atomic ratio of 0.49, which possessed the highest TiB 2 content and matrix phase consisting of Fe and Fe 2 B. However, modulus of rupture (MOR) test indicated that composite with titanium excess (Ti:B atomic ratio of 0.525) was characterized by the highest bending strength, due to successful elimination of Fe 2 B intermetallics. [ABSTRACT FROM AUTHOR]

Plywoods, particleboards and medium density fibreboards are currently used in the construction of houses, furniture, partitions, etc. These usually incorporate some form of formaldehyde as part of the adhesive system. Formaldehyde-based adhesives are known to be harmful as formaldehyde emissions during manufacture and after installation are known to be carcinogenic and have other undesirable health effects. This and other environmental concerns have in the recent past led to an interest in ‘green’ adhesives from biological sources that are sustainable and environmentally friendly. Green adhesives are one of the green building practices, which aim to construct buildings that are environmentally responsible, economically viable and healthy places to live and work. The objective of this investigation was to explore environmentally friendly biobased adhesives for plywood manufacturing. This study proposes a natural biobased adhesive that was developed using soya flour, phenol, Plaster of Paris and an agro-based powder as the binder. A comparison of modulus of rupture of the plywood developed using the proposed soya-based adhesive with popular plywoods, including the traditional urea-formaldehyde based plywood has also been undertaken. The three-point bend test (to identify the modulus of rupture) was conducted for all the plywoods compressed at a fixed pressure. It was observed that the soya-based adhesive imparts greater strength to the plywood than the formaldehyde-based adhesive. It is also desirable for wood and wood-based composites to have fire-retarding and microbial-resistant properties by utilising non- toxic additives and treatments. Traditional methods of achieving these objectives have been harmful; for example, timber has been treated with arsenic-based chemicals to make it resistant to microbes. This paper also presents future research directions to render wood-based composites free of toxic additives as well as being sustainable and environmentally friendly. [ABSTRACT FROM AUTHOR]

Abstract: In this work, Al2O3 self-flowing castables (SFCs) were produced based on various cement contents. The SFCs were sintered at 1273K, 1573K and 1773K and the exhibited properties were experimentally determined. Among the properties determined in this work are bulk density (BD), apparent porosity (AP), water absorption (WA), cold crushing strength (CCS), modulus of rupture (MOR) and fracture toughness (K IC). It is found that additions of 5% cement lead to SFCs with maximum MOR and K IC values after firing at 1773K. Firing at 1573K leads to a reduction in both, MOR and K IC. In SFC containing 3% cement, maximum K IC values of 3.53MPam1/2 were achieved after firing at 1573K. In the low cement SFCs (1wt%) after firing at 1773K the exhibited K IC values were below those obtained in either the SFC-3 or SFC-5, but they were significantly high (3.43MPam1/2). [Copyright &y& Elsevier]

Highlights: [•] Effects of heat treatment temperature and duration on MOR and MOE were studied. [•] The MOR and MOE values were predicted by artificial neural network (ANN). [•] MOR and MOE decreased with increasing heat treatment temperature and duration. [•] ANN was quite successful in the prediction of MOR and MOE values. [•] It was shown that ANN can be used successfully for predicting MOR and MOE values. [Copyright &y& Elsevier]

Highlights: [•] The deep relative notched beam results agree closely with Bazant’s Type 2 size effect law and give initial fracture energy. [•] The RILEM total fracture energy was calculated from the nearly complete post-peak softening load-displacement curves. [•] The analysis of comprehensive fracture tests will give better understanding of the size effects on structure load capacity. [•] The analysis will improve the design of concrete structures. [ABSTRACT FROM AUTHOR]

Abstract: Due to the fact that there are various types of wall tiles in the Egyptian market, of different qualities and prices, the aim of this research paper is to evaluate the properties and characteristics of tiles obtained from the local Egyptian market and attempt to identify the reasons for such differences. In other words, investigate the reasons why some tiles are more superior in quality than others. Test specimens were obtained from the local Egyptian market for fourteen factories. The mechanical properties (namely flexural strength) and physical properties (namely water absorption and apparent porosity) were measured, as they reflect the strength, the endurance during handling, as well as, the conditions to which the tiles are expected to be exposed to during use. The impact resistance and hardness were tested as well. Also, the phases (both major and minor) developed during the firing (maturing) step of manufacturing were identified. A correlation was made between the measured properties and the formed phases. The results showed that samples which yielded high physical and mechanical properties are those that constituted mainly the major phases, specifically, mullite and quartz, while those that contained impurities in the raw materials inevitably resulted in the development of minor phases, in addition to the major phases, had a negative effect on the measured properties. Consequently, it is feasible to obtain tiles that satisfy the requirements of ISO 13006 specification provided that the used raw materials are free (as much as possible) from impurities such as hematite, magnesium, and calcium. [Copyright &y& Elsevier]

Abstract: Solid wood railway ties have widely been used in the railway system in North America. With decreasing average log diameter and quality, laminated wood railway ties have been developed but used on a very limited scale due to the added cost for adhesive and labour. With significant technological advances made by the wood adhesive industry recently, it is considered timely to investigate the feasibility of fabricating laminated wood railway ties using the new structural adhesives. This study was aimed at developing laminated railway ties using low grade hardwoods to meet the North American performance specifications. A two-component polyurethane structural adhesive was used to bond hard maple (mainly) and yellow birch (limited) lumber of No. 3B Common grade to manufacture 16 ties following four fabricating procedures. The modulus of elasticity (MOE) and modulus of rupture (MOR) of laminated wood ties were evaluated. The key findings were (1) the average MOR of the ties of type A-2 (i.e., laminating first followed by creosote treatment) met the AREMA specifications, however, the average MOE was 3% lower than the required value; and (2) both MOE and MOR of the ties of type A-3 (i.e., CCA treatment first followed by laminating) satisfied the specifications. It is feasible to fabricate laminated wood ties using low grade (No. 3B Common) hardwoods and a proper structural adhesive. [Copyright &y& Elsevier]

Abstract: This paper investigates and compares the cracking moment and modulus of rupture in deep and normal beams. Eight high-strength-self-compacting concrete (HSSCC) deep beams and nine high-strength concrete (HSC) normal beams are casted and tested. The results from ACI 318-95 and CSA-94 codes show the discrepancies in values of modulus of rupture for HSSCC deep and normal beams. These differences are due to non-consideration of load transfer mechanism in deep beams and high strength of concrete. Based on the present study ACI 318-95 is recommended for calculating modulus-of-rupture in HSSCC deep beams whereas CSA-94 is suggested for HSC normal beams. [Copyright &y& Elsevier]

Abstract: This paper compared the results of experimental test of the biaxial flexural tensile strength of concretes to that of the uniaxial flexural strength according to the size of specimens. The uniaxial and biaxial flexural strengths in this study were obtained from the classical modulus of rupture (MOR) test and the biaxial flexural test (BFT) recently developed by Zi and Oh. We estimated load-strain relationship on the bottom surface of BFT specimens and three different sizes were considered to investigate the effect of the size of specimens. The average biaxial flexural tensile strength was greater than the classical modulus of rupture test. However, at the same time, the stochastic deviation of the biaxial test was greater than the modulus of rupture test. The load- strain relationships of two strain gages placed in the bottom surface of specimens is almost identical. [Copyright &y& Elsevier]

Abstract: This study includes an analysis of the applicability of current models used for estimating the mechanical properties of conventional concrete to self-compacting concrete. The mechanical properties evaluated are: modulus of elasticity, tensile strength, and modulus of rupture. An extensive database which included the dosifications and the mechanical properties of 627 mixtures from 138 different references, was used. The models considered are: ACI, EC-2, NZS 3101:2006 (New Zealand code) and the CSA A23.3-04 (Canadian code). The precision in estimating the modulus of elasticity and tensile strength is acceptable for all models; however, all models are less precise in estimating the modulus of rupture. [Copyright &y& Elsevier]

Abstract: This article presents experimental research work oriented toward developing practical design tools for industrial application, and illustrates the potential benefits of the synergistic effect of an ASTM C 618 Class F fly ash (FA) and a high-range polycarboxylate superplasticizer (SP) in the production of conventional concrete. The different concretes considered in this study were produced with mass substitutions of cement by FA between 15% and 75%, and a target slump of 200mm±20mm. The total water content was minimized through the use of an optimum SP dosage that resulted in water reductions of 18%, 15% and 11% respectively for the reference mixtures of w/b =0.5, w/b =0.55, and w/b =0.6, which leads to the same percentage reductions of cement. Heat release and heat flow were analyzed through isothermal and semi-adiabatic calorimetry, illustrating that heat release per unit mass of cement is independent of w/b, contrasting with the time of setting results that vary by several hours between the three different w/b ratios. The paper highlights the beneficial effect of the SP in terms of cement reduction and slump retention. Correlations between the FA substitution and slump loss, setting times, compressive strength and static modulus of elasticity (E) were established and they represent very useful tools for the practical applications of the results. Compressive strength developments up to an age of 56d are also reported, as well as correlations between the modulus of rupture and compressive strength or splitting tensile strength at an age of 28d. [Copyright &y& Elsevier]

Abstract: This study was made to determine some mechanical properties such as compression strength parallel to grain, modulus of rupture, and decay resistance of wood treated with some environmentally-friendly borates. Sodium tetrafluoroborate (SFB), ammonium tetrafluoroborate, (AFB), and ammonium pentaborate octahydrate (APB) were used as borates. Wood specimens were prepared from Oriental beech (Fagus orientalis L.) and Scots pine (Pinus sylvestris L.). Before tests, wood specimens were impregnated with aqueous solutions (0.25%, 0.50%, 1.50%, and 3.00%) of borates according to ASTM D 1413-76. Results showed that compression strength parallel to grain (CSPG) and modulus of rupture (MOR) of wood specimens treated with borates were lower compared to untreated control specimen. In general, our results showed that the higher concentration levels of borates, the lower mechanical properties of wood resulted. Borate treated wood showed considerable resistance to the decay fungus compared to that of untreated control specimen. [Copyright &y& Elsevier]

Abstract: The European norm UNE 12326 for roofing slate defines the mechanical properties of a slate tile through the Bending Strength test, which defines the modulus of rupture (MoR) of the tile. This MoR is related to the durability of the slate, and is one of its main commercial quality properties. During the prospection task previous to open a new slate quarry, it is crucial to define the MoR. The Bending Strength test needs proper slate tiles and a flexion press. To supply these slate tiles it is frequently necessary to open experimental quarry fronts, which are very expensive, and do not guarantee the viability of the quarry. Therefore, a method which could reduce the costs and time for the mechanical characterization would be very useful. In this work we have tried to relate the MoR to the mineralogical and petrographic characteristics of slate, using the Petrographic Examination test, also part of UNE 12326. This test contemplates the finding of a numerical index called Mica Stacking Index (MSI) which quantifies the mica layers fabric. We collected fifteen samples of roofing slates from the Northwest of the Iberian Peninsula and we studied them by using the Bending Strength and Petrographic Examination tests, plus mineralogical quantification using X-ray diffraction and measure of the illite crystallinity (Kubler Index) to determine the metamorphic grade. We have found a strong positive correlation between MoR values and MSI, and a negative correlation between MoR and Mica percentages. These correlations may be used to deduce the MoR, reducing costs during the exploitation labours in roofing slate mining, and also can be used in the quality controls on a working slate quarry. [Copyright &y& Elsevier]

• Determination of tensile strength of glass fiber reinforced polymer (GFRP) bars using flexural testing. • Flexural testing of GFRP is simple and accurate. • The correlation between tensile strength and rupture modulus is done using Weibull weakest link model. • The comparisons with direct test results show very good agreement. This paper presents an experimental and theoretical study on finding tensile strength of glass fibre reinforced polymer (GFRP) reinforcing bars using flexure testing. The tensile strength of these bars is their primary property which must be determined before placing them in concrete members. Direct tensile testing of the bars is tedious and often not practical. In the presented work, the three-point flexure test is proposed as an alternative for direct tensile testing of GFRP bars. The flexure test is quick and easy to setup. The tensile strength in a flexure test is referred to as the modulus of rupture which for brittle materials, is generally higher than tensile strength determined in direct tensile tests. Research presented in this paper shows the correlation of the modulus of rupture to the tensile strength of the GFRP bars. The detail procedures for testing, determination of the cracking load in flexure test, and the subsequent procedures for calculations of tensile strength using the Weibull's weakest link model are presented and discussed. The experimental part includes flexure tests on bars with diameters ranging from 8 mm to 32 mm, followed by calculations of rupture moduli and correlated tensile strengths. Bars with 8 mm, 13 mm and 16 mm diameters were also tested in direct tensile test and the results were used for comparisons with the correlated tensile strengths from flexure test. The results of this work confirm that flexure testing can provide easy and reliable method for obtaining tensile strength of GFRP reinforcing bars. [ABSTRACT FROM AUTHOR]

Novel ceramic tile/lead oxide nanocomposites were designed and assembled based on doping standard ceramic tiles with lead oxide nanoparticles to serve as promising alternative candidates for γ-ray shielding. Various techniques were used to examine the structural properties of the newly formed lead oxide nanoparticles-doped ceramic tile composites including Fourier transform infrared spectrophotometer (FT-IR), X-ray diffraction (XRD), Energy dispersive X-ray (EDX), Thermal gravimetric analysis (TGA), and Field emission-transmission electron microscope (FE-TEM). The main parameter tested in order to characterize the mechanical properties of the newly formed nanocomposites was the modulus of rupture. Since the doping material used in this study was lead oxide nanoparticles, it was found that as its content increased in the ceramic body from 0.0 to 10.0 wt%, the modulus of rupture increased from 1.753 ± 0.07 to 2.674 ± 0.11 MPa, respectively. The curvature of the tiles' edges, the percentage of water adsorption, and their bulk density were among the physical properties examined. The mass attenuation coefficients of the tested samples were evaluated at different γ-ray photon energies (from 59.53 to 1332.50 keV), in terms of the weight percentage of lead oxide nanoparticles. To confirm the γ-rays shielding capabilities of assembled nanocomposites, other shielding parameters were computed, including the mean free path, the effective atomic number, the half value layer, and the effective electron density. It was found that the ceramic tile containing 10.0 wt% lead oxide nanoparticles had the highest value of mass attenuation coefficient, effective atomic number, and effective electron density and the smallest value of half value layer and mean free path, with respect to all studied nanocomposites. This results proved that as the lead oxide nanoparticles content of ceramic-tile nanocomposites increased (from 0.0 to 10.0 wt%), so did their γ-ray shielding ability. Finally, it can be concluded that ceramic tile-loaded-lead oxide nanoparticles exhibited significant improvements in the γ-rays shielding parameters compared to that filled with bulk lead oxide under the same weight percentage. • Incorporation of PbO NPs with different wt% in ceramic tiles. • The modulus of rupture values are ranged between 1.753 ± 0.07 and 2.674 ± 0.11 MPa. • Water adsorption percentages are decreased from 18.98% to 17.60%. • The bulk densities are increased from 2.09 ± 0.75 to 3.06 ± 0.38 g/cm3. • The assembled ceramic tiles exhibited better γ-rays shielding than standards. [ABSTRACT FROM AUTHOR]

Abstract: The present paper reports the testing of 12 alkali-activated mortars and a control ordinary portland cement (OPC) mortar. The main aim is to develop cementless binder activated by sodium silicate powder. An alkali quality coefficient combining the amounts of main compositions of source materials and sodium oxide (Na2O) in sodium silicate is proposed to assess the properties of alkali activated mortars, based on the hydration mechanism of alkali-activated pastes. Fly ash (FA) and ground granulated blast-furnace slag (GGBS) were employed as source materials. The ratio of Na2O-to-source material by weight for different mortars ranged between 0.038 and 0.164; as a result, alkali quality coefficient was varied from 0.0025 to 0.0365. Flow loss of fresh mortar, and shrinkage strain, compressive strength and modulus of rupture of hardened mortars were measured. The compressive strength development of alkali activated mortar was also compared with the design equations for OPC concrete specified in ACI 209 and EC 2. Test results clearly showed that the flow loss and compressive strength development of alkali-activated mortar were significantly dependent on the proposed alkali quality coefficient. In particular, a higher rate of compressive strength development achieved at early age for GGBS-based alkali-activated mortar and at long-term age for FA-based alkali-activated mortar. In addition, shrinkage strain and modulus of rupture of alkali-activated mortar were comparable to those of OPC mortar. [Copyright &y& Elsevier]

Abstract: This paper reports on preliminary investigation of the properties of randomly oriented strandboard which had waterborne or powdered copper naphthenate incorporated into the board during manufacture. When compared to zinc borate-treated controls, the mechanical properties of strandboard were not adversely affected by treatment with either form of copper naphthenate. In general, values for mechanical properties followed the trend untreated controls>waterborne CuN=powdered CuN>ZnB. Water absorption and dimensional properties followed a similar trend. This preliminary study suggests that CuN is a viable alternative treatment for engineered wood composites. [Copyright &y& Elsevier]

The amount of lumber graded by machine stress rating (MSR) has continued to increase since the development of the technology in the early 1960s. Accuracy of lumber strength estimation by X-ray method is reported to be equal to that of MSR. This study examined whether lumber specific gravity and strength can be accurately estimated with radio frequency waves if the moisture content influence in a signal passed through the lumber thickness can be eliminated. Strength of a radio frequency signal passed through the lumber thickness was measured at 6.35 mm intervals along the length of lumber central axis. A linear regression predictive equation was estimated relating modulus of rupture (MOR) to measured signal voltage. Correction for the influence of moisture content on MOR resulted in a predictive equation with an R2 of 0.59. Validation results based on the developed equation gave an R2 of 0.67. The results indicate potential for accurate radio frequency estimation of MOR if adequate correction for moisture content influence is performed. [Copyright &y& Elsevier]

Chemical modification of rubber wood (Hevea Brasiliensis) was carried out by impregnating the wood with styrene and in combination with a crosslinker Glycidyl Methacrylate (GMA). Polymerization was carried out by catalyst heat treatment. The dimensional stability in terms of % volumetric swelling and anti-shrink efficiency was determined and found to be improved on treatment. Water absorption was also found to be decreased considerably for treated wood samples. Mechanical strength of the treated samples in terms of modulus of rupture and modulus of elasticity were also found to be improved. The wood polymer interaction was confirmed by FT-IR spectroscopy. Biodegradability of the wood/polymer composites was determined and found to be improved on treatment with styrene/styrene-GMA. [Copyright &y& Elsevier]

The development of new particleboards from tropical fruit peels with low thermal conductivity as a component of construction panels for energy conservation of building is the main purpose of this study. Durian (Durio zibethinus) peels and coconut (Cocos nucifera) coir fibers were used as the raw material to manufacture particleboards. Two main parameters were investigated namely binder types, (UF 12%, PF 6% and IC 3%) and board density. In general, the effect of adhesive type on the properties of boards was not obvious whereas that of the density was more significant on most properties of boards.Experimental investigation indicated that the mechanical strength of all boards such as modulus of rupture and modulus of elasticity increased with increasing board density, but it is still rather low. However, this decreased the dimensional stability, measured in term of thickness swelling, and thermal conductivity as well.Finally, as the raw materials are agriculture waste, manufacturing particleboards is therefore an economic and interesting option. Such natural particleboards with a low thermal conductivity could be utilized for specific applications as in insulating ceiling and walls. [Copyright &y& Elsevier]

A series of experiments were carried out to examine the resistant capacity of a chemically treated hard wood, Anthocephalus cadamba (Roxb) Miq. to thermal and termite degradation. The treatment with thermosetting resins viz. urea formaldehyde (UF), melamine formaldehyde (MF) and phenol formaldehyde (PF) at 31–33 levels of weight percent gain (WPG) increased the strength property i.e. modulus of rupture (MOR) by 7.50–21.02% and stiffness i.e. modulus of elasticity (MOE) by 9.50–12.18% over the untreated one with no remarkable effect on specific gravity. The treated samples were found resistant to termite attack, while the untreated one was badly damaged by termites on 12 months'' exposure to a termite colony. The thermal degradations of untreated and treated wood samples were studied using thermogravimetric (TGA) and differential thermogravimetric (DTG) techniques at heating rates 20 and 30 °C min−1 in temperature range 30–650 °C. The treated wood was found to be thermally more stable than the untreated one. [Copyright &y& Elsevier]

Silicon nitride-bonded silicon carbide (SNBSC) and aluminosilicate-bonded silicon carbide (ASBSC) refractories have been prepared by reaction bonding. The percentage of silicon nitride or aluminosilicate in the refractory was varied from 15 to 25 wt.%. The modulus of rupture of the refractories increases with molybdenum disilicide (MoSi2) infiltration. These are resistant to molten zinc, lead, and aluminium, but are attacked by molten sodium sulphate. The thermal expansion coefficient of silicon carbide refractories varies from 3.1×10−6 to 5.3×10−6 °C−1 for the temperature from room temperature to 1000 °C. [Copyright &y& Elsevier]

As an alternative to conventional cement-based materials, natural fibers have been demonstrated to effectively enhance mechanical property. A reduced in size particle termed microcrystalline cellulose (MCC) has been explored as mortar reinforcement. In this manner, this study focused on its effects on the cement pastes early hydration modulus of rupture (MOR). Loadings of MCC ranging from 0.1 to 1.0% in relation to cement mass was considered. At 7 hydration days the MOR, as well as the degree of hydration, dry bulk density, water absorption and pore volume indexes were determined. It was found that 0.2% of MCC has a greater influence on the MOR at 7 hydration days, performing 8,06% better than reference (0.0% MCC). This composite also presented the lowest indexes for water absorption and pore volume, while presenting the highest degree of hydration and dry bulk density. An analysis of variance (ANOVA) returned the significance of %MCC in the early hydration MOR and physical parameters. • ANOVA clearly indicates that the MOR is influenced by MCC addition. •High %MCC decreases the degree of hydration at early ages. •MOR, degree of hydration, and physical parameters performed best with 0.2% MCC. [ABSTRACT FROM AUTHOR]

• Modulus of rupture of a rectangular glass plate depends on the loading arrangement. • Modulus of rupture of a glass plate is only an apparent material property. • Modulus of rupture of a glass plate is independent of the plate aspect ratio. • Small samples give a large scatter and erroneous conclusions for modulus of rupture. • Large-sample moduli may be converted to moduli for other plates and loading systems. Strength determination of rectangular float glass plates is commonly carried out by standard tests. Different standards include different requirements of the specimen geometry, loading set up, sample size, etc. It is known that the modulus of rupture depends on the specimen's area. This paper shows that it is also dependent on the loading system, and the dominating parameters affecting the experimental modulus of rupture are investigated. The loading system significantly affects the modulus of rupture and this finding raises a question with respect to the testing guidelines appearing in different standards and the experimental results thereby obtained. [ABSTRACT FROM AUTHOR]

• Effects of high-content FA and LSF on flexural toughness of ECC was explored. • LSF improved early-age cracking strength of ECC & enhanced its flexural strength. • LSF did not reduce flexural toughness up to deflection of L /150 (T 150). • Increasing FA/OPC ratio decreased T 150 of ECC beams. • R T ,150 from ASTM C 1609 better distinguished pre-peak and post-peak behavior. This study explores the effects of high-content fly ash and limestone filler partial replacement for portland cement and silica sand, respectively on the flexural toughness parameters of engineered cementitious composites (ECC). Various groups of mixtures having variable fly ash/portland cement ratio and different levels of limestone filler were prepared. ASTM C1609, JSCE-SF4 and the Post-Crack Strength method were employed to appraise the flexural toughness parameters of the ECC mixtures at 3, 28 and 90-d. The results show that according to ASTM C1609, JSCE-SF4 and the Post-Crack Strength method, limestone filler did not significantly affect the flexural toughness, while the flexural toughness of ECC beams decreased when the fly ash content increased. Considering deflection capacity, specimens made with a FA/OPC ratio of 1.2 without limestone filler achieved higher ductility at all curing ages. Owing to its superior crack resistance and toughness compared to normal concrete, ECC with high fly ash content and limestone filler could be a sustainable alternative construction material in diverse civil engineering applications. ECC with enhanced ductility compared to normal concrete could offer increased crack resistance, durability and better resilience. [ABSTRACT FROM AUTHOR]

• Mixture with 1.20% macro and 0.30% micro fiber had generally highest toughness. • HFR-SCC must have minimum the FR-index of 0.7 to display the deflection-hardening. • The best flexural performance was obtained with FR-index of 1.04 for HFR-SCC. • All methods except for ASTM C1018 agreed in terms of flexural toughness values. • All HFR-SCC specimens clearly exhibited excellent ductility performance. The purpose of this study was to investigate the effect of total volume fraction and combinations of macro and micro steel fiber on the workability and mechanical as well as flexural performance of hybrid reinforced self-compacting concretes (HFR-SCC). A sum of five fiber reinforced SCC mixtures containing a total volume fraction fiber of 1.00% and 1.50% were designed as two single fiber reinforced mixtures with only macro steel fiber and two hybrid fiber reinforced as well as the control mixture without fiber. To interpret the fresh properties of HFR-SCC, slump flow diameter, T 500 and J-ring test were performed. The compressive strength, splitting tensile strength, flexural strength, load-carrying capacity, flexural toughness and ductility were measured to evaluate the mechanical and flexural performance of HFR-SCC. The attained test results for fresh properties revealed that although decrease in the workability of FR-SCC mixtures happened with the increase in total volume fractions of fibers, all steel fiber reinforced SCC mixtures provided the workability limits of EFNARC. The flexural toughness values increased with the total volume fraction of fibers from 1.00% to 1.50%. The hybrid reinforced SCC specimens were exhibited superior the compressive strength, flexural toughness and ductility compared to single fiber reinforced SCC specimens. Also, HFR-SCC mixture with 1.20% macro and 0.30% micro steel fibers gave the best results in terms of mechanical and flexural performance due to increase in macro steel fiber volume fraction and higher fiber reinforced index with 1.04 as well as synergistic blends of macro and micro steel fibers. [ABSTRACT FROM AUTHOR]

• Relationship between EPS, glass fiber, and flexural properties of LWGRC was studied. • EPS and glass fiber play an independent role in LWGRC. • Empirical formula was developed to forecast the MOR of LWGRC with EPS. • Too high or too low fiber content will reduce the fracture energy of LWGRC. Lightweight glass fiber reinforced cement (LWGRC) with good thermal insulation can be produced by using expanded polystyrene (EPS) particles. In this study, the influence of EPS and glass fiber on the modulus of rupture (MOR) and toughness of GRC was investigated. The fiber mass fraction is 0% ~ 3.6%, and the EPS volume fraction is 0% ~ 36%. No matter how much glass fiber is, the relative MOR has the same proportional relationship with the relative density of LWGRC. The empirical formula based on power function can well show the relationship between relative MOR and relative density. The higher the content of EPS, the more obvious the plastic characteristics of LWGRC. When the content of EPS is in a range of 0% to 18% (by volume), the fracture energy of LWGRC increases with the increase of glass fiber content. When the content of EPS is in the range of 27% to 36% (by volume), the fracture energy of LWGRC with 2.4% (by mass) fiber is higher. Too high or too low content of glass fiber is harmful to the fracture energy of LWGRC. [ABSTRACT FROM AUTHOR]

Abstract: Earthworms through their feeding, casting, and burrowing activity can have significant influence on a wide range of soil physical properties. A research was conducted in order to study the role of earthworms in modifying the properties of tilled and cultivated soil. Undisturbed soil mesoscoms (500mm i.d.×250mm height) with and without tillage and cultivation, with and without earthworm''s inoculation were tested and physical properties were compared with existing properties in native field. Earthworms (Allolobophora caliginosa) were inoculated directly in mesoscoms and represented the following treatments: non-cultivated non-tilled (C0T0), cultivated non-tilled (CT0), non-cultivated tilled (C0T) and cultivated tilled (CT). Inoculated soils were incubated for six weeks at 21±1°C. Inoculated soils reflected significantly higher aggregate meanweight diameter (MWD=2.75mm), higher clod density (CD=1.66Mgm−3), higher modulus of rupture (MR=410kPa), and lower hydraulic conductivity (HC=0.85cmh−1) compared with non-inculcated soils. The MWD of inoculated soils for different treatments was in following order: T0C>T0C0 >TC>TC0. [Copyright &y& Elsevier]

• A combined Lamb wave propagation and machine learning method was proposed. • The Lamb wave velocity was highly correlated with the MC, density, MOE and MOR of wood. • The MOE and MOR of wood specimens were predicted accurately using the proposed method. • The proposed method outperformed the conventional ultrasonic methods for the prediction of MOE. Accurate nondestructive prediction of the mechanical properties of wood is a critical quality control task for timber grading. Currently, the ultrasonic wave method is widely used for this purpose, which overestimates the static mechanical properties of wood. To resolve this challenge, this paper proposes a robust machine learning-based model for predicting the modulus of elasticity (MOE) and modulus of rupture (MOR) of wood with varying moisture content (MC) using the guided Lamb wave propagation method. It combines the Lamb wave velocity with the "group method of data handling" to predict the mechanical properties of wood. The effect of MC and density on the Lamb wave velocity and the mechanical properties of seventy green poplar wood specimens were analyzed and discussed. It was shown that the Lamb wave velocity is highly sensitive to the MC, density, and mechanical properties of wood. It enables the guided Lamb wave propagation to be used as a reliable method for nondestructive timber characterization. The MOE and MOR of wood specimens predicted by the developed machine learning model were compared with those from the three-point bending tests, and the obtained accuracy was revealed to be higher than that obtained in the literature using the conventional ultrasonic method. It was concluded that the proposed combined Lamb wave propagation and machine learning method offers a strong tool for nondestructive prediction of the mechanical properties of wood. [ABSTRACT FROM AUTHOR]