Tensile Strength Test Research Articles

ENHANCING COLD MIX ASPHALT PERFORMANCE WITH GEOPOLYMER TECHNOLOGY

Generally, Cold asphalt emulsion mixtures (CAEM) produced and compacted at ambient temperatures. The main objective of this study is to investigate the improvement of the performance for mixtures by the addition of geopolymers based on cementitious material by preparing the asphalt samples using three concentrations of geopolymer utilized as a substitute for limestone filler (LF),The mechanical properties of the mixtures were evaluated using the Marshall test, Indirect Tensile Strength (ITS) test, Kim test and Water sensitivity test TSR. The test results revealed that the concentration of (NaOH) has a substantial influence on the structure and characteristics of geopolymers, enhancing Marshall stability, ITS, and rut resistance. CAEM with geopolymer considerably improved Marshall stability and deformation resistance especially those containing fly ash.CAEM with geopolymer provides larger ITS conditioning and a TSR over 100% better than hot mix asphalt HMA. Furthermore, it is noteworthy to mention that the addition of geopolymer has somewhat improved the mechanical properties and durability characteristics of the CAEM.

Development of a Green Corrosion Inhibitor from Lophatherum Gracile Extract for Steel Protection

Corrosion constitutes a significant challenge in the context of infrastructure development, with particular implications for steel materials. One common method for preventing corrosion is the application of inhibitor materials. Inhibitors are classified into two main categories: organic inhibitors and inorganic inhibitors. Inorganic inhibitors are costly and may have adverse environmental effects. Consequently, organic inhibitors that are cost-effective and environmentally benign were developed. One plant that has the potential to be used as an organic inhibitor is Lophatherum gracile B. (Lophatherum gracile Brogn), due to its antioxidant compounds that can prevent corrosion. The objective of this research is to analyze the effect of the Lophatherum gracile B. extract inhibitor on the corrosion rate and its inhibition efficiency on reinforcing steel. The weight loss method was employed to determine the corrosion rate in a 3% sodium chloride (NaCl) medium, with concentration variations of 0%, 2%, and 4% over a duration of 24, 72, and 96 hours. The findings indicated that the lowest corrosion rate was observed at the 4% concentration, while the highest rate was noted at the 0% concentration. The inhibition efficiency of the Lophatherum gracile B. extract was determined to be greater than 66%. The qualitative analysis of the macro photo material structure indicated that the steel surface treated with Lophatherum gracile B. extract exhibited a reduced level of corrosion in comparison to the control sample. Furthermore, the tensile strength testing demonstrated that the decline in the tensile strength of steel could be attenuated through the use of inhibitors. These findings suggest that the Lophatherum gracile B. extract is an effective inhibitor material for reinforcing steel.

Design and Development of a Novel Nano-hybrid Dental Composite: Antibacterial Silica Nanocomposite for Dental Use

Resin based dental composites is one of the promising dental materials that serves as an alternative to metal and amalgam restorations, as they resemble natural tooth and widely used in restorative dental treatments such as tooth decay and oral lesions. Despite several ongoing researches and innovations, the primary challenges associated with composite restorations are their limited durability, sensitivity, shrinkage and leakage. This research aimed to address these challenges and develop an innovative dental composite resulting in a minimal discomfort to the patient and improve long term therapeutic eficacy. To overcome these challenges silica Nano- particles, with antibacterial agent was incorporated. Nano- particles of silica acted as filler, which was extracted from a bio-waste (rice husk). The addition of anti-microbial agents helped to minimize leakage due to shrinkage as these materials have small particle size, offering a wide range of biological, chemical and mechanical properties. This was followed by characterization techniques which includes; SEM, XRD, FTIR and particle characterization that were evaluated and compared. The peaks of Silicon dioxide in XRD was recorded at 21.67, 38.38 and 44.68. Extracted silica particle size 47. 66 μm was further reduced to Nano size with an average size of 200 nm. FTIR spectrum showed the relative transmittance at 1000- 1090 cm<sup>-1</sup>. The results met the standard measures and was much cheaper than currently used in dental industry. In future, comparative analysis testing including compressive or tensile strength and anti-bacterial testing can be performed that may further prove its potential and can be followed by clinical trials also.

Physical, Chemical, and Mechanical Characterization of Coated Date Palm Leaf Fiber from the Middle Region of Iraq for Potential in Civil Engineering Application

Date palm leaf fibers are suitable for engineering applications due to their availability, inexpensiveness, and ecofriendliness. However, there is a risk of biodegradation in the long term. This paper explores date palm leaf fiiber (DPL) properties and the protection of the fibers from biodegradation to enhance their lifespan. To this end, two coating materials (bitumen and polyurethane) were used separately. Physical and mechanical tests were conducted to determine the most effective material to coat the DPL fibers. To comprehensively assess the performance of the coated fibers, their morphology was examined via microstructure analysis using scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX) tests. This analysis encompasses their material properties, chemical composition, water absorption, and degradation, providing a thorough understanding of the protective coatings’ impact on the DPL fibers. The tensile strength test results revealed that the maximum tensile strength of the bitumen coated date palm fiber (DPLB) is 7.4 MPa. The tensile strength is two times greater than the polyurethane coated date palm leaf fiber (DPLP) and untreated date palm leaf fiber (UDPL). The results of the degradation test revealed that the weight loss percentage is equal to 45.5 and 25 in the case of the UDPL and DPLP fibers, and no loss in weight in the case of the DPLB fiber. Out of all the test results, bitumen is considered the best due to its ability to resist the attack of chlorides and sulfate ionspresent in groundwater on top of being cheap, simple, and efficient.

Mechanical properties of modern restorative “bioactive” dental materials - an in vitro study

This study aimed at assessing the mechanical properties and degradation of commercial bioactive materials. The bioactive materials (Activa Bioactive Restorative, Beautifil Flow Plus F00, F03, Predicta Bulk Bioactive) and composite resin Filtek Supreme Flow were submitted to flexural and diametral tensile strength tests (FS, DTS), modulus of elasticity (ME) evaluation, and analysis of aging in 70% ethanol and saliva on their hardness and sorption. The results for DTS ranged from 33.16 MPa (Beautifil Flow Plus F03) to 47.74 MPa (Filtek Supreme Flow). The highest FS was 120.40 MPa (Predicta Bulk Bioactive), while the lowest values were 86.55 MPa (Activa Bioactive Restorative). Activa Bioactive Restorative showed the lowest ME, as well as the highest water sorption both in alcohol and artificial saliva. Moreover, aging in saliva induced a significant decrease in hardness for Activa Restorative (p < .01). Alcohol storage caused a significant decrease in hardness for all materials (p < .0001). All tested materials met the basic requirements for light-curing materials in terms of DTS and FS. However, all materials showed higher sorption in alcohol than in saliva, while hardness decreased significantly after 30 days. Predicta Bulk Bioactive presented the highest mechanical parameters, initial hardness, and the lowest sorption of alcohol and saliva.

Sustainable Approach to Utilization of Waste Glass Fibers and Basalt Powder as Potential Additives in Epoxy-Based Composites for Reparation of Concrete Structures

The growing production of glass fibers is a major challenge due to the later problem of their sustainable recycling. This article reports the potential use of post-production waste glass fibers and basalt powder as additives in resin compounds designed for repairing concrete elements. The aim of this research was to develop a repair compound based on epoxy resin with the addition of waste materials, offering a competitive alternative to currently available repair compounds on the market by utilizing lower-cost materials and addressing pro-environmental aspects through waste reuse. The prepared research samples were characterized by varying proportions of basalt powder (0–20%), ground HP 12 fibers (40/60%), and HP 6 fibers (10/20%). A series of tests, including tensile strength tests, were conducted as part of this study to determine the effect of the applied additives on the ultimate tensile force and maximum deformations. Abrasion resistance tests were also carried out to evaluate the impact of basalt powder as a filler on enhancing the abrasion resistance of the designed repair compound. Additionally, SEM and EDS analyses were used to evaluate the uniformity and distribution of the additives within the sample. This study examined samples containing varying percentages of basalt powder and fibers, both virgin and milled. The most significant reinforcement effect was observed for sample E/20HP/20bp, where its tensile strength decreased by 8%, while its abrasion resistance increased by 44% compared to the reference sample. The obtained results confirm that incorporating waste materials as additives into epoxy resin can significantly enhance the mechanical properties of repair compounds while reducing cost and promoting environmental protection. In addition, the repair compound developed complies with the selected principles within the 6Rs environmental regulations: RECYCLING (reuse of waste glass fibers), RETHINK (reduce environmental impact by avoiding landfill), REDUCE (minimize the use of virgin glass fibers in the production of repair compounds) and REPAIR (increase the efficiency of repairing damaged concrete structures). Furthermore, as the percentage of basalt powder increases, the abrasion resistance of the repair compound improves. The obtained repair compounds may serve as an alternative to currently used compounds for the repair of bridges and factory floors.

Microstructural and mechanical properties of boron carbide (B4C) coated RDSO wear plate sample

In this research, a comparative investigation was carried out on the microstructural and mechanical characteristics of boron carbide (B4C) coated RDSO (Research design & standard organization, India) approved steel sample and uncoated RDSO steel samples intended for applicable as wear plates of ballast cleaning machines which is a railways track maintenance machine. Wear plates of ballast cleaning machines are subjected to extreme abrasion & impact stresses because they directly come in contact with railways ballast. Microstructural examinations were performed using scanning electron microscopy (SEM) and optical microscope to characterize the coating’s homogeneity, adhesion, and interfacial bonding with the steel substrate. Mechanical tests, including hardness testing, tensile strength, and wear tests, were conducted to understand the coated sample’s performance compared to the uncoated counterpart. Results indicated that the average micro-hardness values, 428 ± 10 HV and 302 ± 10 HV was obtained using Vickers hardness test done on the samples B4C coated RDSO sample and uncoated RDSO sample respectively. The average coefficient of friction (COF) for the carbide-coated sample was 0.33 under a 10 N load, while the uncoated sample had a COF of 0.64. This demonstrates that the carbide coating greatly improves wear performance. This comparative analysis suggests that B4C-coated steel is a promising railways for wear plate applications in ballast cleaning machines, providing increased lifespan and better performance.

3D Printing of Virucidal Polymer Nanocomposites (PLA/Copper Nanoparticles)

Metallic nanoparticles with virucidal properties dispersed in a polymeric matrix have gained prominence in the scientific community as a rapid and effective alternative that employs the additive manufacturing (AM) or 3D printing method. This study aims to produce filaments for 3D printing using polymer nanocomposites based on polylactic acid (PLA) and copper nanoparticles (CuNPs) in different proportions. The virucidal activity of various proportions of nanoparticles in PLA was investigated. The composites were produced following a mixture design (DOE) with concentrations ranging from 1% to 2% copper nanoparticles, which were blended with PLA using a single-screw extruder. The samples were characterized by thermogravimetry (TG), differential scanning calorimetry (DSC), tensile strength testing, and fracture analysis using scanning electron microscopy (SEM). A thermal analysis of the composites indicated that the CuNPs contributed to an increase in the degradation temperature and crystallization of the PLA. Sample S7 (1.25% of CuNPs) exhibited a 4% increase in the degradation temperature compared to pure PLA. The best tensile strength results were observed in sample S7 (1.25% of CuNPs), 30% more than sample S3 (1.33% of CuNPs) due to good material cohesion, as evidenced by microscopy analyses. Regarding virucidal analyses, most composites demonstrated virus inhibition activity.

Experimental Investigation of Young Concrete Properties Needed for Proper Analysis of Concrete Pavements Behavior During the Hardening Process

In this paper there are presented results of experimental investigation of young concrete properties. During design process of concrete structures there is used number of mechanical properties of concrete that are not normally part of the concrete specifications. Desirable values are often related to primary parameter of concrete – mean concrete compressive strength. Some of them are poorly or even not at all described at the very beginning of concrete maturing. This paper describes results obtained from common mechanical test of compressive and tensile strength, shrinkage strain and two author’s test dealing with creep under constant compressive and tensile stresses of young concrete and also temperature development in quasi-adiabatic conditions.

Investigation of Near-Infrared Spectroscopy for Assessing the Macroscopic Mechanical Properties of Cross-Linked Polyethylene During Thermal Aging

The present study investigates the relationship between the near-infrared (NIR) spectral characteristics of cross-linked polyethylene (XLPE) insulation materials and their macroscopic properties, with the aim of establishing a reference framework for non-destructive material aging analysis. Accelerated thermal aging tests were conducted on samples of XLPE cables. These samples underwent Fourier-transform infrared spectroscopy (FTIR), elongation at break (EAB), and tensile strength (TS) tests. The temporal variation curves of the carbonyl index (CI), EAB, and TS were obtained at aging temperatures of 105 °C, 135 °C, 155 °C, and 180 °C. Additionally, NIR spectroscopy was performed on the aged XLPE samples, producing absorbance curves corresponding to different aging times at these temperatures. The absorption peaks of ‘C-H (-CH2-)’ (1730 nm/1764 nm) were analyzed to determine their temporal variation patterns. Finally, a correlation analysis was conducted between the NIR results and those of the FTIR, EAB, and TS tests, revealing numerical relationships between NIR characteristic peaks and FTIR, EAB, and TS data. These quantified correlations demonstrate that NIR can effectively represent macroscopic mechanical properties, thereby simplifying the procedures for monitoring material aging and providing valuable results without requiring destructive testing. Results indicate that there is a certain feasibility in replacing traditional cable aging tests with NIR.

An effect of nano alumina and nano titanium di oxide with polypropylene fiber on the concrete: mechanical and durability study

For a long time, researchers have worked to improve the qualities of cement-based mixes. Because of their small size, strong reactivity, and huge surface area, nanoparticles are becoming more and more regarded as one of the greatest substitutes for cement because of their capacity to increase durability and strength. This work presents the results of an experimental investigation into the strength and durability properties of fiber-reinforced concretes with polypropylene (PP) fibers added to the concrete by volume and nano Al2O3 and nano TiO2 are used as partial substitutes for cement. Nano Al2O3 and nano TiO2 particles used ranged in size from 30 to 300 nm. The specimens were cast using cement blended nano Al2O3 and nano TiO2 percentages of 1%, 2%, 3%, and 4% by weight of cement. M55 grade concrete was employed for the casting process. The addition of PP fibers to the concrete was 0.5% by volume. The specimens underwent a battery of mechanical tests, including microstructural testing, compression testing, split tensile strength testing, and rupture modulus testing. Furthermore, tests for durability factors such as porosity, sorptivity, and degradation were conducted, and the findings are presented. By comparing the outcomes, it was shown that the inclusion of 0.5% PP fibers and 2% nano Al2O3 or nano TiO2 improved the mechanical qualities, but a decrease followed this in strength. The findings demonstrated that 2% nano Al2O3 combined with 0.5% PP fiber had a greater mechanical strength than 2% nano TiO2.

Towards coupling agent-free composites made from regenerated cellulose/HDPE by UV radiation-induced cross-linking

ABSTRACT This research aims to enhance fibre-matrix adhesion in bio-based fibre-reinforced polyolefins without using adhesion promoters. The primary focus is to establish a cross-linking mechanism between cellulose fibres and polyethylene by applying UV irradiation to a UV-transparent matrix and UV-absorbing fibres. The influence of UV treatment on the composite properties is evaluated by tensile, interfacial and interlaminar shear strength tests. The UV irradiation decreases the critical fragment length in single fibre fragmentation tests, indicating an improved fibre-matrix adhesion. The UV-irradiated composites’ tensile strength and Young’s modulus are found to be ~10% (for 3- and 8-minute irradiation) and ~50% (for 8-minute irradiation), respectively, higher than those of the untreated samples. Furthermore, the UV irradiation leads to an improvement in the interlaminar shear strength by 25%. The variation of the UV-irradiation time (3 min and 8 min) and the comparison of the properties of semi-finished composite sheets and composites also reveal chemical and physical changes in the regenerated cellulose fibres due to heat adsorption. The proposed mechanism of interfacial crosslinking is confirmed by FTIR spectroscopy. The results suggest an approach to overcome poor compatibility between hydrophobic polyolefin matrix and hydrophilic cellulose-based fibres, resulting in adhesive-free bio-based composites.

Evaluating and optimizing metals for kitchen equipment production

This study assesses the mechanical properties and corrosion resistance of three stainless steel grades (316, 201, and 304) used in kitchen equipment manufacturing, emphasizing their performance based on specific metrics. Brinell hardness tests revealed values of 310.13 HB for 316, 286.49 HB for 201, and 276.13 HB for 304. Impact strength and tensile strength tests showed that 316 outperformed the others due to its higher chromium, nickel, and molybdenum content and enhanced mechanical properties from annealing, quenching, and tempering processes. Fatigue strength testing indicated that 316 had the highest endurance strength. Corrosion tests confirmed that all three grades exhibited no corrosion. These results indicate that stainless steel 316 has superior mechanical properties and corrosion resistance, making it an excellent choice for manufacturing durable and reliable kitchen equipment.

Research on Two-Layer Polymer Composites Alternatively Obtained in a Constant Magnetic Field.

The aim of this research was to obtain two-layer polymer composites with favorable mechanical and functional properties. The composites consisted of one lower layer of polymer with less elastic properties, containing no admixtures, and one upper layer of polymer with more elastic properties, containing plant admixtures, in the amount of 10% by weight of either goldenrod (Solidago virgaurea L.), or of turmeric (Curcuma longa L.). The admixtures S. virgaurea and C. longa were intended to introduce new biodegradable and medicinal properties without causing too much deterioration of physical or mechanical properties. Some polymer composites additionally contained magnetic particles in the form of carbonyl iron (Fe) in the amount of 20% by weight. The tests of mechanical tensile strength of the composites, water absorption, frost resistance, and surface contact angle were performed. Microscopic examinations determined the roughness of the cross-sectional surfaces. A constant magnetic field with magnetic induction B, which was an additional external factor changing the properties and structure of two-layer polymer composites, was also used in the research.

Prototype of Self-Service Electronic Stethoscope to Be Used by Patients During Online Medical Consultations.

This article presents the authors' design of an electronic stethoscope intended for use during online medical consultations for patient auscultation. The goal of the project was to design an instrument that is durable, user-friendly, and affordable. Existing electronic components were used to create the device and a traditional single-sided chest piece. Three-dimensional printing technology was employed to manufacture the prototype. Following the selection of the material, a static tensile strength test was conducted on the printed samples as part of the pre-implementation investigations. Results: Tests on samples made of PLA with a 50% hexagonal infill demonstrated a tensile strength of 36 MPa and an elongation of 4-5%, which was deemed satisfactory for the intended application in the stethoscope's manufacture. The designed and manufactured electronic stethoscope presented in the article can be connected to headphones or speakers, enabling remote medical consultation. According to the opinion of doctors who tested it, it provides the appropriate sound quality for auscultation. This stethoscope facilitates the rapid detection and recognition of cardiac and respiratory activity in humans.

A Taguchi-based study on the control factors of reinforced composites with the fiber of coir and pineapple leaves.

The use of composite materials, whether metallic or non-metallic, is becoming more popular nowadays because of some of their superior characteristics compared to the use of wood and metallic materials alone. From this perspective, a new natural fiber reinforced composite by varying the fiber orientation was developed in this study using coir and pineapple leaf fiber. This work uses the Taguchi method to investigate the different effects of control factors on mechanical and physical characteristics of the fabricated natural fiber-based composites. Various control factors were used, including fiber ratios, angles of orientation, and mat types. The testing was conducted in accordance with ASTM standards, and the results were validated through various statistical analyses including Taguchi orthogonal array analysis, confirmation tests, regression analysis, and analysis of variance (ANOVA). Based on the analysis and validation, the highest mean impact strength was found 53.93J/cm2, tensile strength 31.94MPa, flexural strength 46.365MPa, Rockwell hardness number 77, and lower water absorption rate only 3.62%. From the confirmation test, margin of errors was found to be 4.84%, 2.59%, 2.35%, 6.62%, and 2.334% for impact, tensile, and flexural strength, Rockwell hardness, and water absorption test respectively. The variation of the experimental and predicted results was observed from the regression analysis, and it was 2.93 to 0.4J/cm2, 2.12 to 0.79MPa, 3.54 to 0.33MPa, 2.33 to 0.8 RHN, and 0.92%-0.13% for impact, tensile, and flexural strength, Rockwell hardness, and water absorption test respectively. Overall, ANOVA analysis was used to examine the effects of different control variables, and it was discovered that the angle of orientation of fibers had a substantial impact on flexural strength and water absorption rate were 72.30% and 70.89% respectively. Similarly, mat types on tensile strength and Rockwell hardness with 46.47% and 50.67% respectively. In addition, the impact strength was most significantly affected by the wt.% ratio of fibers, which was approximately 50.32%. From the above characteristics and their environmentally friendly behavior, these composites can be used in the place of synthetic fiber-based products.

Evaluation of Open-Graded Friction Course Mixes with Agro-Waste–Derived Natural Fibers

Abstract As an agrarian economy, India produces the second-largest amount of agricultural waste globally. The practices of indiscriminately disposing of this waste in open lands or burning it in agricultural fields give rise to significant environmental and health concerns. With an increasing need for sustainable road construction materials and practices, engineers are continuously looking for the use of agricultural and plantation-based resources, particularly natural fibers. In order to address problems like binder draindown and raveling associated with high binder content and low fine content, this study focuses on the open-graded friction course (OGFC), which incorporates fibers. Under the investigation on the potential applications of natural fibers, including banana fiber (BNF), sisal fiber (SIF), pineapple fiber (PNF), sunn hemp fiber (SHF), and cellulose fiber (CLF), the study assesses various mix design parameters across 12 combinations, including bulk density, air voids, stone-on-stone contact, binder draindown, and abrasion loss (aged and unaged) at different binder contents, fiber lengths, and dosages. Results indicate an optimum binder content of 6.0 % for all fiber-reinforced OGFC mixes. Grey relational analysis and indirect tensile strength (ITS) tests further validate the improved performance of these mixes, showcasing reduced draindown, and abrasion loss, and enhanced ITS with the incorporation of natural fibers. The comprehensive evaluation of mix design properties ranks BNF as the top-performing, followed by PNF, SIF, and SHF, as indicated by the grey relational grade. This research emphasizes the potential of using agricultural waste for sustainable infrastructure development and promoting eco-friendly practices in the construction industry.

Analysis of the porous system structure, permeability coefficient and mechanical resistance of pervious concrete

ABSTRACT When used as a surface layer on permeable pavements, pervious concrete promotes water percolation, thus helping urban water runoff management. Water percolation occurs due to its porous structure, and interconnected pores are fundamental for its efficiency. To better understand pervious concrete, this study aimed to analyse the porous structure and mechanical and hydraulic properties of pervious concrete. Compressive strength, flexural tensile strength, porosity and permeability coefficient tests were performed. The porous structure was characterised using three approaches: ImageJ software, Sketchup software and scanning electron microscopy. According to hardened state results and Brazilian technical standards, pervious concrete can be used cast-in-place for pedestrian traffic or light vehicular traffic areas. Pervious concrete pores’ length, perimeter, Feret’s diameter and width increase, while circularity and the number of pores decrease as the void volume increases, indicating that as the volume of voids in pervious concrete increases, the pores become larger, more elongated and smaller in quantity. Good to excellent correlations were found between the concrete’s compressive strength, flexural tensile strength and permeability coefficient and the concrete’s porosity, pore area, pore volume and geometric tortuosity, although different image analysis methodologies were used to obtain the porous structure data.

Effect of Using Types and Concentrations of Ureolytic Bacteria on Flexural Capacity of High-Strength Concrete with Self-Healing Concrete Capabilities

Abstract Concrete’s deflection and cracking are influenced by flexural capacity. High-strength concrete tends to have high hydration rate, making it susceptible to microcracks, thus, early maintenance is required. The weak nature of concrete against tensile forces allows microcracks to occur and can propagate into macrocracks if the cracks are not detected. Therefore, an innovation emerged called self-healing concrete enabling concrete to cover microcracks independently. This method can be used to heal concrete cracks, involving bacteria in concrete mixture that are active when cracks occur by producing calcite (CaCO3) to close the cracks. In this study, ureolytic bacteria of genus Bacillus sp., Staphylococcus sp., and Solibacillus sp. were used. Specimen used was beam with dimensions of 400mmx100mmx100mm, which was strengthened with 1D10 mm tensile reinforcement to prevent brittle collapse of beam. Variations in bacterial mixture used were 0%; 0.5%; 0.6%; and 0.7% of the cement weight which encapsulated in diatomaceous earth altogether with urea and Ca2+ as precursors and nutrient broth as bacterial nutrients. Encapsulation pellet dosage was 10% from fine aggregate weight. At initial testing stage, cracking load amounting 70% of 7 days non-bacterial concrete flexural tensile strength was imposed to give initial cracks to concrete, then, treatment was conducted for 28 days by immersion in water to visually observe the self-healing process of calcite growth (CaCO3) for 7, 14, 21 and 28 days. After accomplishing crack healing process, ultimate flexural tensile strength testing was performed. The highest average flexural capacity results were obtained in high-strength concrete with 0.6% Bacillus sp. bacteria of 6.34 ton with an average calcite length of 41.00 mm. To analyse atomic structure characteristics of bacterial concrete, XRD testing was carried out and the results showed that bacterial concrete of Bacillus sp. had the highest percentage of amorphous phase, i.e., 82.63%, and contained 33.66% calcite compounds.

Study on strength properties of lightweight foamed composite with 0.6% volume fraction treated kenaf fibre

The Lightweight Foamed Composite (LFC) exhibits inherent limitations in mechanical strength due to its porous structure, hindering its wider application. This study presents a novel approach to enhancing LFC's mechanical strength properties by incorporating Treated Kenaf Fibre (TKF), a domestically available high-yield crop in Malaysia, offering a green and effective solution for “Sustainable Composite Reinforcement.” To optimize fibre incorporation, raw kenaf fibres were pre-treated with a 1.5 M NaOH solution for 12 hours. Subsequently, a 0.6% TKF by Volume Fraction (Vf) was integrated into the LFC mix. The fresh and hardened density of Treated Kenaf Fibre Lightweight Foamed Composite (TKFLFC) was controlled within 1200 ± 5% kg/m3. Next, the mechanical properties evaluation of TKFLFC involved compressive, flexural, and splitting tensile strength tests. By the 28-day mark, the compressive strength of LFC-TKF 0.6 showed a moderate improvement of 4%, while the flexural and splitting tensile strengths significantly increased by 56% and 62%, respectively, compared to LFC-Control. A performance index evaluation emphasizes the contribution of TKF in enhancing LFC's mechanical strength at the same densities. These findings demonstrate the potential for utilizing TKF in LFC as a green, sustainable civil construction material, offering valuable insights and opportunities for innovation.