Compressive Strength Values Research Articles

Advanced Predictive Modeling of Concrete Compressive Strength and Slump Characteristics: A Comparative Evaluation of BPNN, SVM, and RF Models Optimized via PSO

This study presents the development of predictive models for concrete performance, specifically targeting the compressive strength and slump value, utilizing the quantities of individual raw materials in the concrete mix design as input variables. Three distinct machine learning approaches—Backpropagation Neural Network (BPNN), Support Vector Machine (SVM), and Random Forest (RF)—were employed to establish the prediction models independently. In the model construction process, the Particle Swarm Optimization (PSO) algorithm was integrated with cross-validation to fine-tune the hyperparameters of each model, ensuring optimal performance. Following the completion of training and modeling, a comprehensive comparison of the predictive accuracy among the three models was conducted, with the aim of selecting the most suitable model for incorporation into an optimized objective function. The findings reveal that among the chosen machine learning techniques, BPNN exhibited superior predictive capabilities for the compressive strength of concrete. Specifically, in the validation set, BPNN achieved a high correlation coefficient (R) of 0.9531 between the predicted and actual outputs, accompanied by a low Root Mean Square Error (RMSE) of 4.2568 and a Mean Absolute Error (MAE) of 2.6627, indicating a precise and reliable prediction. Conversely, for the prediction of the concrete slump value, RF outperformed the other two models, demonstrating a correlation coefficient (R) of 0.8986, an RMSE of 9.4906, and an MAE of 5.5034 in the validation set. This underscores the effectiveness of RF in capturing the complexity and variability inherent in slump behavior. Overall, this research highlights the potential of integrating advanced machine learning algorithms with optimization techniques for enhancing the accuracy and efficiency of concrete performance predictions. The identified optimal models, BPNN for compressive strength and RF for slump, can serve as valuable tools for engineers and researchers in the field of construction materials, facilitating the design of concrete mixes tailored to specific performance requirements.

Evaluation of cement-treated recycled concrete aggregates for sustainable pavement base/subbase construction

Rapid urbanization and population growth have caused a substantial rise in the generation of all kinds of waste globally. The use of recycled waste not only can replace the enormous volume of virgin materials used in construction but also alleviate environmental concerns by lowering landfilling loads. This study aims to evaluate the feasibility of using non-treated and cement-treated recycled concrete aggregates (RCA) in pavement base and subbase layers. A detailed study focused on the strength, durability and microstructural aspects of treated RCA. To fulfill this, experimental test program and analysis covered particle-size distribution, Los Angeles abrasion, aggregate impact value, modified Proctor compaction, unconfined compressive strength (UCS), weight loss under wet-dry cycles, and scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis. The recycled aggregates are found to show excellent physical and mechanical characteristics in terms of abrasion and aggregate impact values. Cement treatment has shown to significantly enhance the strength and durability characteristics of RCA, rendering it suitable for pavement base/subbase layer application. RCA samples treated with a cement content of 3 % and above (by weight) are found to satisfy the minimum specified unconfined compressive strength (UCS) values of 2 MPa at 7 days of curing, according to the Texas Department of Transportation (TxDOT) and Austroads guidelines for pavement base and subbase layer applications. However, a relatively higher cement contents (5 % and 7 %) is required to meet the minimum 7-days UCS criterion of 3 and 4.5 MPa for base layer applications of low- and high- volume roads, respectively, according to Indian road standards (IRC SP 72 (2015) and IRC 37(2018)). Cement-treated samples with 2 % cement or above showed minimal weight loss after 12 alternate wet-dry cycles, which was well within the maximum permissible limit (14 %) specified in various standards for stabilized materials. Additionally, microstructural investigations have clearly showed formation of hydration products corroborating the mechanism behind strength gain with time. Findings from this study provide references to promote the use of RCA in construction of pavement base and subbase layer, contributing towards the goal of net zero set by the United Nations.

Effects of fly ash, activator ratio and steel fiber on freeze–thaw cycle, sulfuric acid, thermal conductivity and impact resistance of silica fume based AAHSMs

This study is focused on the effects of Class C fly ash (FA), NaOH/Na2SiO3 (SH/SS) ratio and steel fiber (STF) on the freeze–thaw (F-T) cycle, sulfuric acid, thermal conductivity and impact resistance of silica fume (SF) based alkali activated high strength mortars (AAHSMs). In the AAHSM mixtures, FA in different proportions (10 %, 15 %, 20 % and 25 %) is used instead of SF by weight. All the mixtures are prepared with water-to-binder rate of 0.32. F-T cycle results exhibit that the flexural strength (ffs) and compressive strength (fc) values of SF based AAHSMs without and with STF are less affected than those of ordinary Portland cement (OPC) based high strength mortars (OPCHSMs) without and with STF. After 300 F-T cycles, the ffs and fc values of SF based AAHSMs without and with STF are still over 14 MPa and 95 MPa, respectively. After exposure to 20 % sulfuric acid solution for 90 and 180 days, the SF based AAHSMs without and with STF exhibit super performance (i.e., fc values between 78.95 MPa and 96.81 MPa), while the surfaces of OPCHSMs without and with STF are disintegrated. Additionally, the effects of F-T cycle and sulfuric acid solution on SF based AAHSM and OPCHSM are examined with the microstructure analyses. Thermal conductivity results show that the SF based AAHSMs without and with STF perform better than the OPCHSMs without and with STF. The thermal conductivity results of OPCHSMs without and with STF vary between 0.630 W/m.K and 0.697 W/m.K, while the thermal conductivity results of SF based AAHSMs without and with STF range from 0.507 W/m.K and 0.623 W/m.K. Thermal conductivity results are adversely influenced by increasing STF content in the SF based AAHSMs and OPCHSMs. Impact resistance results show that the SF based AAHSMs without and with STF perform better than the OPCHSMs without and with STF. Moreover, the impact resistance values increase, as the amount of STF used in the SF based AAHSMs and OPCHSMs increases.

Production and Characterization of Porous Anorthite Ceramics Using Sugar Process Solid Waste, Chamotte and Coal Powder Additives

Press filter cake is a solid waste produced during sugar production process and includes carbonates and organic components. In this study, coal powder in different percentages (from 10 wt.% to 50 wt.%) was mixed with 35 wt.% press filter cake and 65 wt.% chamotte composition to produce porous anorthite ceramic products with different apparent porosity percentages. The anorthite phase was observed as the dominant crystalline phase in all fired samples. The firing shrinkage values sharply increased after adding higher than 40 wt.% coal powder to composition. In addition, apparent porosity values were changed from 49% to 70%. Compressive strength values reduced from 18 MPa to 1.73 MPa while percentages of ground coal were increasing. Microstructural analysis also showed that the porosity values of the sintered samples showed important changes depending on the amount of coal additive. The thermal conductivity values showed a reduction from 0.113 W/mK to 0.064 W/mK while increasing the percentage of ground coal. Micro-computed tomography (Micro CT) analysis was performed for 40wt. % coal powder added composition and the total porosity value was found as 60.2%.

Pengaruh Penggunaan Zeolit dan Serat Agave Sisalana Terhadap Kuat Tekan dengan Metode Self Compacting Concrete (SCC)

Self Compacting Concrete (SCC) is concrete innovation which does not require vibrations during installation and compaction. SCC concrete can flow freely with its weight and is capable of filling a mold well, ensuring perfect compaction without vibration. In 1988, in order to eliminate or reduce the need for vibration to achieve density and thereby reduce the labor required for concrete placement, SCC was developed in Japan. In this research, the production of SCC was investigated by replacing the fine aggregate in the SCC mixture by 3%, 7% and 11% of zeolite material and by adding 0.005% of agave sisalana fiber of cement weight. The 15/30 cm concrete cylinders were used in 16 samples for compressive strength. It is shown that the values of flowability, filling capacity, and permeability decrease with increasing use of zeolite content based on the results of the research conducted. The results of the compressive strength test show that the variation of 7% zeolite + 0.005% sisalana fiber has the highest value of compressive strength at FAS 0.43, with an average of 38.46 MPa, and the highest value of compressive strength at FAS 0.45, with an average of 37.07 MPa.

Use of Various Industrial and Eggshell Wastes for the Sustainable Construction Sector

The alternative composites’ production alleviates the serious problem generated by global warming. Methods to reduce the amount of cement used in concrete production, for example, are being investigated to determine how to reduce carbon dioxide emissions in many applications. Egg shells and various industrial wastes, which are recommended to use in the construction sector at an appropriately high rate, also cause serious environmental damage. Bottom ash (BA) and marble powder (MP) wastes are used today in civil engineering applications. In addition, it is important to increase the use of eggshells due to their rich calcium carbonate content. In this work, BA and MP wastes were blended with eggshells to produce cement paste composites. Two different sets of composites were prepared during this study. The composites were prepared with cement (80%), BA (20%), and MP (20%) wastes by weight with 0.3%, 0.75%, 1.5%, and 2.5% eggshell waste. The fresh (flow table), physical (dry unit mass, apparent specific gravity, and porosity), mechanical (unconfined compressive strength and flexural strength), and durability (water absorption, seawater resistance) tests were conducted. According to the experimental results, the composites can be classified as lightweight construction materials. The test results showed that 0.75% eggshell by weight of cement in bottom ash and marble powder can be used as an optimum value for better performance. The bottom ash mixtures groups are higher water absorption and porosity values when referring to the marble powder mixture groups. The highest compressive strength value was found at 56.03 MPa in the MP mixture group and 52.79 MPa in the BA mixture groups with these optimum eggshell combinations at 56 days. The MP mixture group showed better resistance to seawater when referring to the bottom ash blended mixtures. Laboratory-produced composites are possible candidates for cost-effective and environmentally friendly building materials. The eggshells have a promising alternative binder for concrete in the near future and they are utilized together with industrial wastes such as BA and MP in sustainable concrete construction.

Mechanical properties investigation on recycled rubber desert sand concrete

The mechanical properties of recycled rubber desert sand concrete were studied to determine the effect of the replacement rate of recycled rubber and desert sand. The replacement rates of recycled rubber aggregates were set to 0 %, 5 %, 10 %, and 15 %, respectively, and for dessert sand aggregates were set to 0 %, 10 %, 20 %, and 30 %, respectively, during concrete preparation. The concrete's compressive, tensile, and freeze-thaw mechanical properties were tested at each replacement rate. The experimental results show that when the replacement rate of desert sand increases from 0 % to 30 %, the replacement rate of recycled rubber is 15 %, and the splitting tensile strength of concrete shows a pattern of first increasing and then decreasing. When the replacement rate for desert sand is 30 %, the replacement rate for recycled rubber rises from 0 % to 15 %, and the splitting tensile strength shows a pattern of first decreasing. With replacement rates of 10 percent for recycled rubber aggregate and 20 percent for desert sand aggregate, the damage to the concrete from external forces is relatively ideal. The compressive strength values are the highest, and the split tensile strength is the best, demonstrating good compressive and tensile strength. The results of CO2 emission analysis show that as the amount of recycled rubber increases, the CO2 emissions per unit volume of concrete also increase. The interface of the micro-optical structure in the concrete is straightforward, the pores are few, and it exhibits good mechanical properties. The concrete undergoes freeze-thaw cycles with relatively stable changes in compressive strength and split tensile strength, demonstrating a solid freeze-thaw resistive mechanical property.

Optimizing foaming agent concentration and recycled fine aggregate content to enhance mechanical and durable properties of foam concrete mixes

This research explores the impact of using recycled fine aggregates from construction and demolition wastes (CD-RFA) through the replacement of natural sand in proportion of 0 %, 10 %, 30 %, 50 %, 70 %, and 100 % for making foam concrete mixes. Protein based foaming agent was diluted with water in ratios of 1:20, 1:40 and 1:60. It was found that with the increase in the proportion of recycled fines, the porosity, sorptivity and water absorption of foam concrete mixes increases significantly. At the same time, a downward trend in the mechanical characteristics was noted. However, the obtained values of compressive strength, flexural strength, and split tensile strength of 22.35, 5.68 and 2.27 MPa were found to be well within the ACI 523 R 2014 recommended ranges of 8–22, 3–6.4 and 1–2.2 MPa, respectively. Hardened density, abrasion resistance, and resistance to sulphates and chlorides attack showed perceptible decline. The present study recommends the replacement of natural sand up to 50 % with CD-RFA. The foam concrete mix prepared using recycled fines will help clearance of a large quantities of CD wastes, thereby benefiting the environment and ecology.

Damage and energy characteristics of coal rock combinations with inclined coal seams under axial loading

A single load compression test of rock-coal-rock assemblages (RCRs) containing coal bodies with different inclinations was carried out with the research background of mining deep, large-steep coal seams. It was found that the larger the inclination angle of the coal body in the RCR samples, the larger the compaction stage of the samples and the smaller the uniaxial compressive strength value. In addition, both the maximum acoustic emission (AE) energy of the samples and the cumulative AE energy at the moment of destruction decreased with the increase of the inclination angle of the coal body in the form of exponential relativities. Also, the input energy and ultimate elastic energy of the samples at the peak stress moment decreased with increased inclination angle of the coal body. Furthermore, both of them changed with the inclination angle of the coal body in accordance with the exponential relationship; meanwhile, when the applied load exceeded the peak strength, the dissipative energy of the RCR samples increased rapidly due to the loss of load-bearing capacity. At the peak moment, the percentage of dissipated energy of the samples increased exponentially with the increase of the inclination angle of the coal body. This study has certain reference significance for the prevention and control of dynamic disasters during the mining of large angle coal seams.

The evaluation of the effects of different curing methods on concrete

This research explores the impact of various curing methods on the water absorption and compressive strength of concrete. To evaluate these properties, 45 cubes of mix ratio 1:2:4 were tested under different curing methods namely water ponding, sand, polythene sheet coverage, sawdust and water sprinkling. All the cubes were cured at an average laboratory temperature. Water absorption, compressive strength and SEM-EDX tests were conducted on the concrete cubes after curing for 7, 14 and 28 days. The study found that the water absorption and compressive strength values at 7, 14, and 28 curing days ranged from 1.53 to -1.12% and 21.30 to 31.40 N/mm2, respectively and varied depending on the curing method used. All the cementitious compositions of the concrete cubes of all the curing methods showed an increase with the increase in curing age and ranged between 0.01 and 81.67, while their SEM images revealed heterogeneous microstructures consisting of aggregates, cement paste, and voids.Sand and sawdust curing produced the highest and lowest compressive strength values, respectively. Based on these findings, sand curing was identified as the most favourablemethod. Further investigation should be carried out.

Effect of iron‐containing fillers on heat release kinetics and strength properties of polyester resin

AbstractThe influence of filling by iron‐containing fillers on the heat release kinetics and mechanical properties of industrial unsaturated polyester resin PN‐1 is investigated experimentally. The iron ore concentrate, electrostatic precipitator dust, high alumina cement grade HAC‐1, shavings made of cast iron, fine grade sand are used as fillers. To improve the strength characteristics of polyester resin composites the small amount (0.2–1.0 wt%) of organosilicon additives such as synthetic silicone rubber, tris(trimethylsiloxy) phenylsilane, octamethyl cyclotetrasiloxane are used. The heat release kinetics is studied for different ratios between accelerator (cobalt naphthenate) and initiator (cyclohexanone peroxide). The time to reach the maximum temperature of the heat release is significantly reduced when a large amount of iron ore concentrate is used as filler. The temperature of maximum heat release decreases and the time to reach it increases when adding electrostatic precipitator dust in small amount of 5 wt% to the high filled by iron ore concentrate (295 wt%) composite system. The optimum in strength indicators associated with the ratio of different fractions in systems consisting of two fillers of different properties and granulometric composition is found. The highest values of compressive strength in the cement–iron ore concentrate and sand–iron ore concentrate systems are observed. An increase in the strength characteristics of composites by 15%–20% with organosilicon additive introduction is observed. The addition of the silicone rubber increases the strength properties of samples the most among all additives considered.Highlights Effect of filling by iron‐containing fillers on the heat release kinetics and mechanical properties of polyester resin is found. The time to reach the maximum temperature of the heat release is significantly reduced when the resin is filled by a large amount of iron ore concentrate. The temperature of maximum heat release decreases when the electrostatic precipitator dust in small amount is added to the high filled by iron ore concentrate. An increase in the strength characteristics of composites by 15–20% with introduction of organosilicon additives is observed.

Pengaruh Air Laut terhadap Kuat Tekan, Permeabilitas, dan Mikrostruktur Beton Geopolimer dengan Flyash dan Tanah Putih sebagai Pengganti Semen

The increasing infrastructure development of an area is sometimes located in an aggressive environment, one of which is in coastal areas so that direct contact with sea air cannot be avoided. This research aims to determine the effect of sea water on geopolymer concrete using fly ash and white soil as cement substitutes with testing parameters for compressive strength, permeability and microstructure. The test objects used were cylindrical in shape measuring 150x300 mm and 100x200 mm. The ratio of fly ash and white soil used was 85%:15% and the activator used was NaOH 8M and Na2SiO3 with a ratio of 1:2,5. The mixture proportion using a ratio of 1 fly ash: 1,497 sand: 2 split: 0,451 alkali activator with a mutual plan is 35 MPa. Tests were carried out after the concrete had gone through a curing process for 56 days, then the concrete was conditioned without soaking and with soaking for 28 days. Tests were carried out at concrete ages of 56 and 87 days. The test results show that geopolymer concrete with the influence of sea water has a higher compressive strength value and a smaller permeability coefficient compared to concrete without the influence of sea water. Microstructural testing of geopolymer concrete under the influence of sea air produces a matrix-shaped structure morphology that is denser with fewer pores compared to concrete without the influence of sea air.

An influence of geothermal water, temperature and pressure on the hydration of multicomponent cement binders

Cement pastes of different compositions were hydrated in a geothermal solution with the simultaneous action of high temperature (150 °C) and pressure (18 MPa) for 7 days. The influence of solution on phase composition and compressive strength of pastes was investigated based on the comparison with hydration in water and using TGA, XRD, FTIR, 29Si, and 27Al NMR. The geothermal solution accelerated hydration and pozzolanic reactions. A higher amount of more thermally stable products was formed. Undesired transformation to crystalline α-C2SH in the samples with the highest C/S ratio was restricted. The uptake of carbonates from the solution led to an increased amount of calcite. As a result, increased compressive strength values were determined. Preferential incorporation of Al3+ into the structure of C-(A-)S-H or hydrogrossular phases depended on the composition of cement pastes.

Recycling of Waste Granodiorite Powder as a Partial Cement Replacement Material in Ordinary Concrete

Abstract In this study, the effect of using waste granodiorite powder (WGP) as a cement replacement material in percentages ranging from 1 to 9% on various physical and mechanical properties of ordinary concrete was investigated. The resistance of produced concretes with WGP to the high temperature effects on the 28 days compressive strength were studied as well. Granodiorite is one of the well-known igneous rocks that have been used in previous research as a replacement for coarse or fine aggregates due to the hardness of its grains. However, rare studies have investigated its powder as a partial cement replacement material. Results showed the ability of investigated WGP with high surface area to act as a supplementary cementitious material that contributed to enhance the results of mechanical and physical properties of concrete. At traditional room temperature, the optimal replacement percentage was 7%, where the 28 days compressive and tensile strengths were improved by 28.3% and 17.3%, respectively. The optimal replacement ratio varied between 7 and 9% in the case of high temperatures, according to exposure time and temperature degree. Statistical and sensitivity analysis was conducted on 66 available compressive strength value represents all variables before and after elevated temperature exposure. While the regression equation showed good R2 value of 85.3%, sensitivity analysis indicated that compressive strength value is most sensitive to temperature, followed by WGP ratio and exposure time, with importance values of 56, 26, and 18 %, respectively. Results showed also that the setting times and consistency was decreased with increasing the replacement ratio with WGP, while the workability was slightly improved up to 5% replacement ratio. Furthermore, microstructure analysis showed that WGP can help to densify the concrete matrix due to its small size and ability to fill the interstitial voids in the concrete matrix.

Experimental study on the mechanical properties of desert sand improved by the combination of additives and bio-cement.

Bio-cement is a green and energy-saving building material that has attracted much attention in the field of ecological environment and geotechnical engineering in recent years. The aim of this study is to investigate the use of bio-cement (enzyme-induced calcium carbonate precipitation-EICP) in combination with admixtures for the improvement of desert sands, which can effectively improve the mechanical properties of desert sands and is particularly suitable for sand-rich countries. In addition, the suitability of tap water in bio-cement was elucidated and the optimum ratio of each influencing factor when tap water is used as a solvent was derived. The results showed that peak values of unconfined compressive strength (maximum increase of about 130 times), shear strength (increase of 27.09%), calcium carbonate precipitation value (increase of about 4.39 times), and permeability (decrease of about 93.72 times) were obtained in the specimens modified by EICP combined with admixture as compared to the specimens modified by EICP only. The incorporation of skimmed milk powder, though significantly increasing the strength, is not conducive to cost control. The microscopic tests show that the incorporation of admixtures can provide nucleation sites for EICP, thus improving the properties of desert sand. This work can provide new research ideas for cross-fertilization between the disciplines of bio-engineering, ecology, and civil engineering.

New Insights Into Application Relevant Properties of Cu2+-Doped Brushite Cements.

Doping of brushite cements with metal ions can entail many positive effects on biological and physicochemical properties. Cu2+ ions are known to exhibit antibacterial properties and can additionally have different positive effects on cells as trace elements, whereas high Cu2+ concentrations are cytotoxic. For therapeutical applications of bone cement, a combination of good biocompatibility and sufficient mechanical properties is required. Therefore, the aim of this study was to investigate different physicochemical and biological aspects, relevant for application, of a brushite cement with Cu2+-doped β-tricalcium phosphate, monocalcium phosphate monohydrate and phytic acid as setting retarder. Additionally, the ion release was compared with a cement with citric acid as setting retarder. The investigated cements showed good injectability coefficients, as well as compressive strength values sufficient for application. Furthermore, no antibacterial effects were detected irrespective of the Cu2+ concentration or the bacterial strain. The cell experiments with eluate samples showed that the viability of MC3T3-E1 cells tended to decrease with increasing Cu2+ concentration in the cement. It is suggested that these biological responses are caused by the difference in the Cu2+ release from the hardened cement depending on the solvent medium. Furthermore, the cements showed a steady release of Cu2+ ions to a lesser extent in comparison with a cement with citric acid as setting retarder, where a burst release of Cu2+ was observed. In conclusion, despite the anticipated antibacterial effect of Cu2+-doped cements was lacking and mammalian cell viability was slightly affected, Cu2+-concentrations maintained the physicochemical properties as well as the compressive strength of cements and the slow ion release from cements produced with phytic acid is considered advantageous compared to citric acid-based formulations.

Evaluation of compressive and diametral tensile strength of novel bioactive material with conventional glass ionomer cement and silver amalgam: An in vitro study.

The aim of this study was to compare the compressive and tensile strength of two different brands of conventional glass ionomer cement (GIC), with new zirconia-reinforced GIC and silver amalgam. Eighty specimens with 20 samples in each group were prepared (Group 1-Fuji IX GIC, Group 2-FX-II Shofu GIC, Group 3-Amalgam, and Group 4-Zirconia-reinforced glass ionomer [Zirconomer]) for compressive strength (CS) using cylinder molds with dimensions 6.0 mm diameter × 12.0 mm height. Eighty specimens using cylinder molds with dimensions 6.0 mm diameter × 3.0 mm height were prepared for testing diametral tensile strength (DTS). CS test was carried out using Micro Universal Testing Machine (Mecmesin, PPT Group, UK) having a crosshead speed of 1.0 mm/min. DTS was determined using Instron universal testing machine at a crosshead speed of 1.0 mm/min. The data were submitted to two-way analysis of varianceand post hoc Tukey tests (alpha = 0.05). The mean CS value was more for Group III (256.2), followed by Group IV (181.2 Megapascals [MPa]), Group II (129.8 MPa), and the least was Group I (117.9 MPa). The mean DTS value was high in Group III (73.7 MPa), followed by Group IV (58.0 MPa), Group II (36.0 MPa), and the least was seen in Group I (23.2 MPa). It can be concluded that although Zirconomer has mechanical properties greater than that of unmodified GICs, additional studies are essential to evaluate its long-time ability.

Effect and mechanism of calcination on improving the hydration activity of titanium extraction slag

Titanium extraction slag (TES) is a special waste residue in China’s Panxi region. It exhibits low hydration activity because of its high titanium content and carbon- and chlorine-based impurities introduced during production. Thus, TES wastes can only be stored in large quantities. Oil and gas wells’ high-temperature and high-pressure environments contribute to TES hydration. However, its hydration activity should be improved to transform it into a well cementing material. The optimal calcination temperature was 550 ℃. Using NaOH (6 %) as an activator, the compressive strength values of the calcined TES cured for 1 and 14 days reach 19.23 and 34.40 MPa, respectively, 65.49 % and 39.78 % higher than those of untreated TES. These values meet oil and gas well cementing construction requirements. X-ray diffraction, 29Si nuclear magnetic resonance, scanning electron microscopy, and other characterization methods indicate that calcination can reduce the content of the glassy phase in TES. However, it induces impurity removal and reduces the degree of glassy phase polymerization. Thus, TES’s ion leaching and deposition rates, hydration, and compressive strength after calcination improved. Therefore, the method proposed in this study can be successfully used to convert TES into new cementing materials for large-scale applications.

Waste glass as an eco-friendly substitute in plastering mortars: analyzing microstructure, thermal, and mechanical properties

This study investigates waste glass (WG) as an environmentally friendly substitute for natural sand in cement mixtures. Plastering mortars were fabricated by replacing sand with WG at proportions of 10%, 20%, and 30%. X-ray diffraction, Thermogravimetry, Scanning Electron Microscopy, and Energy-dispersive X-ray spectroscopy characterized the mortars. Compressive strength was measured at two ages (7 and 28 days) for WG-containing mortars. Results confirm the suitability of waste glass as a sand replacement in mortars, with the 20% WG sample showing optimal compressive strength, contributing to environmental and economic impact reduction. Thermogravimetric analysis of the 30% WG mortar shows a significant difference in mass loss percentages compared to the reference mortar, losing only 3.65% at 28 days versus 7.85%. Additionally, waste glass increased mortar density, reducing porosity and enhancing structural uniformity. Despite a decrease in compressive strength values, the results remain satisfactory for application in the Civil Construction industry. This comprehensive exploration underscores the potential of waste glass as a sustainable alternative, emphasizing its positive effects on both performance and environmental considerations.

Manufacturing of hexagonal cross-section thermoplastic matrix composite parts with automatic filament winding system

Thermoplastic filament winding is a flexible manufacturing method typically used in the production of cylindrical composite structures, allowing for in-situ consolidation without the need for a second consolidation step. The objective of this study is to produce non-cylindrical geometries, typically manufactured using thermoset matrix composites according to the literature, using the thermoplastic filament winding process. For this purpose, glass fiber (GF) reinforced polypropylene (PP) prepreg tapes were used to produce hexagonal cross-section thermoplastic composite parts. The critical process parameters; hot-air heater nozzle temperature, compression roller pressure, the linear speed of mandrel rotation, and corner radius of the mandrel, were determined using the Taguchi experimental design method. The interlaminar shear strength (ILSS) and maximum compressive strength (σmax) values were obtained as 211 MPa and 49.40 MPa as maximum, respectively. ANOVA analysis showed that the corner radius had the most significant impact on ILSS, while mandrel rotation speed and temperature were critical for σmax.