Revista de la Construcción. Journal of Construction

Effect of waste oyster shell powder as additive on properties and sulfate attack resistance of mortar

2023-08-07T08:51:30+00:00

In this study, the waste oyster shell powder was added in mix design to investigate the properties, sulfate attack resistance and sulfide bacterial of concrete. Add 0%, 1%, 3%, 6% and 9% oyster shell powder to the concrete to replace part of the sand. The study conducted flow tests, compressive strength tests, sulfate corrosion resistance and antibacterial tests. From the results, it was found that adding oyster shell powder improved the resistance to sulfate corrosion and antibacterial properties and became more effective as the substitution ratio increased. In addition, the sulfate attack resistance and antibacterial have a linear relationship of mortar with oyster shell powders.

Investigation of plastic hinge length in high-ductility reinforced concrete shear walls

2024-03-05T13:10:46+00:00

In this study, the plastic hinge lengths of reinforced concrete (R/C) cantilever shear walls were analytically determined considering various design parameters. Nonlinear static (Pushover) analyses were conducted on R/C shear wall models and their nonlinear behavior was examined using ABAQUS software. In the study, 72 shear wall models with different parameters were analyzed under the influence of vertical and horizontal loads. Parameters whose effects on plastic hinge length were investigated height/length ratio (H_w/L_w), axial load ratio (N/N_o), and horizontal web reinforcement ratio (ρ_sh). The load-displacement graphs of the modelled shear walls were obtained. The plastic hinge height of shear walls was determined according to the heights of the deformations in the concrete and longitudinal steel reinforcement in the section when the shear walls lateral load decreased by 15%. The analytical plastic hinge lengths (L_pz) were determined with respect to the location of the yield occurred at the longitudinal steel reinforcement of the shear wall. The observed plastic hinge lengths (L_p) were determined based on the height of observed the crush as of the foundation top level in the concrete shear wall model. The relationship between the findings of this study and empirical formulas in the literature was determined. It was determined that there is greater closeness between the values obtained from empirical formulas in the literature and the observed plastic hinge length values. It was observed that the plastic hinge length generally increases as the shear span increases. It was observed that the change in ρ_sh was not a very effective parameter in plastic hinge formation. As the N/N_o decreases, the plastic hinge length values generally increase. The L_p/L_pz ratio varied within the range of 0.15-0.50. In addition to ductility (μ) values were determined by using the displacements determined according to both the crushing occurred in the shear wall concrete and the yield observed in the steel reinforcement. The observed that the ductility value depends more on H_w/L_w ratio as N/N_o ratio decreases.

An alternative approach for increasing the visibility of roads

2024-02-16T12:06:56+00:00

Visibility problems occur on highways that are not sufficiently illuminated at night, endangering traffic safety. Phosphor material, which has a natural glow feature under ultraviolet (UV) light, is planned to increase road visibility in areas with inadequate lighting. Phosphor powder (PP) was used in four different percentages (25%, 50%, 75%, and 100%) as fillers in hot mix asphalt (HMA), reduced to filler size. Asphalt specimens were prepared using a super pave gyratory compactor and super pave volumetric mixture design. Compacted specimens were exposed to artificial 12V UV light for 10-minute intervals in a dark room, and UV light absorption was observed. Visibility analyses were performed on the specimens by taking high-resolution photos with long exposure from a distance of approximately 30 cm from the asphalt specimen using a professional camera. According to the analysis results, the visibility values increased by 200.4%, 378.5%, 538.1%, and 728.5% compared to the reference specimen for substitution rates of 25%, 50%, 75%, and 100%, respectively. Experiments were conducted to determine the behavior of the specimens prepared as phosphorus substitutes in the mixture. After selecting the optimum binder contents, the modified Lottman test procedure was applied to measure the specimens' strength values and moisture sensitivity prepared at optimum ratios. The indirect tensile test results show that the 25% PP-substituted specimen had a better strength value. The tensile strength ratio (TSR) value, the ratio of dry and wet tensile stresses, was determined to have minor moisture sensitivity in the 50% PP-substituted specimen. HWTT was applied to the specimen containing 50% PP content, which exhibited the best TSR ratio, resulting in improved rutting performance compared to the reference specimen.

Evaluating the effective factors of BIM for enhancing the construction interface management

2024-02-19T12:21:28+00:00

Maintaining the proper interface management among the construction stakeholders is becoming more crucial due to the interconnected nature of construction work. Adopting and implementing building information modelling (BIM) technology can aid in the proper execution of construction projects. Therefore, the main goal of this study is to evaluate the effective factors of BIM using DeLone and McLean’s (DM) model. The DM model's factors evaluate the system or technology in terms of system quality, information quality, service quality, and most importantly, the system's net benefits and user satisfaction. The questionnaire was developed with the expert's opinion and the survey was conducted. As megaprojects have more complicated and various levels of information sharing, this study targeted collecting responses from industrial project practitioners in India. From the survey, a total of 166 responses were obtained. Using these data, the frequency test, reliability test, and the relative importance index (RII) were performed. These effective factors of BIM contribute significantly to project performance improvement through proper interface management and communication among stakeholders. The findings of the study emphasized the importance of user satisfaction and the net benefits of BIM. Thus, this study provides further insights to increase the adoption and implementation of BIM technology.

Heavy aggregate and different admixtures efffect on parquets: chrome, magnetite, and quartz-based surface hardener

2023-12-19T16:56:24+00:00

This paper presents the mechanical and micro-structure results of concrete parquet blocks. The blocks were generated by utilizing the same part in the bottom part and by substituting different proportions (40%, 30%, 20%, and 10%) of heavy aggregate like chromite aggregate, magnetite aggregate, normal aggregate, and surface hardener in the upper part. The parquet sample tests were conducted on TS 2824 EN 1338. The test outcomes indicated that utilizing diverse aggregate and chemical materials boosted the abrasion resistance, 40% magnetite and quartz-based concrete parquet block samples demonstrated the best abrasion resistance values. Also, the minimum amount of mass loss was discovered in the samples that possess high water absorption at the freezing-thaw test. The different material substitutions in the sheet of the surface of the concrete parquet block samples altered the tensile strength of the samples, even though they did not bring about an outstanding variation in the compressive strength of the concrete parquet samples.

Mechanical properties of cement-based composites incorporating eco-friendly aggregate of waste rubber

2023-11-01T21:58:13+00:00

The purpose of this study is to evaluate the waste tires that harm the environment as aggregate in concrete and to examine the effect on the mechanical properties of concrete. Three different classes (powder, crumb and chips) of waste rubber with seven different ratios (0%, 4%, 8%, 12%, 16%, 20% and 24%) and two different water to cement ratio (0.4 and 0.5) were used in concrete production. In this regard, this study conducted various experiments consisting of 28 and 90 days of the curing process to determine the properties of unit weight, compressive, flexural, and splitting tensile strength, along with ultrasonic pulse velocity (UPV) and dynamic modulus of elasticity. The waste rubber concrete with the highest compressive strength at the end of 90 days is the concrete that includes 4% waste rubber (0.4WR4) with 58.81 MPa. Concrete containing 8% waste rubber has the highest UPV of 5660 m/s after 90 days. The increase in the water/cement ratio from 0.4 to 0.5 and the waste rubber ratio cause deterioration in the mechanical properties of concrete. Although the use of waste rubbers does not bring an increase in strength, it is feasible to produce high strength concretes with 4% and 8% waste rubber substitution ratios. The water/cement ratio and curing time were highly effective on the mechanical properties of rubberized concrete.

Numerical investigation of the behavior of reinforced concrete beams produced with self-compacting concrete

2024-01-15T10:19:32+00:00

In this study, 1/2 scaled 16 reinforced concrete beams were compared in terms of concrete type, concrete strength, and stirrup spacing. The variables of this study consist of self-compacting concrete and normal concrete as concrete type, C30 and C60 as concrete strength, and without stirrup, 20 cm, 10 cm and 5 cm spacing as stirrup spacing. All elements were tested with 4-point bending mechanism. The stiffness, ductility, load bearing capacity and energy consumption capacity values of the beams were obtained from the load-displacement curves acquired from the experimental study and the elements were compared over them, and the damages of the beams during the experiments were interpreted. In addition to the experimental study, the numerical analyzes of the beams were conducted with the finite element analysis software. Experimental study results were validated by finite element analysis. When all the results were examined, it was concluded that although the initial stiffness of SCC (self-compacting concrete) was less than NC (normal concrete), the ductility of SCC was higher than that of NC, especially in high strength concretes.

Project characteristic-based performance prediction model for school constructions: hierarchical regression approach

2024-02-28T22:58:50+00:00

Project underperformance remains a significant concern in the construction industry. The majority of prior studies have focused on identifying the subjective factors that affect project performance. However, there are currently no in-depth studies evaluating the influence of project characteristics and managerial/organizational obstacles on construction project performance for design-bid-build projects using empirical data. Therefore, this study aims to present a predictive model that illustrates the correlation between project characteristics, managerial/organizational complexity and difficulties, and construction project performance. Project data relating to the construction of 101 public schools within a developing country was collected. Subsequently, the project characteristics were identified, and two performance indicators (schedule performance index and cost performance index) were calculated for each project. A survey was conducted with construction professionals who took part in all of the control and management processes of these school projects to evaluate their managerial and organizational difficulties. Hierarchical regression model approach and correlation analyses were employed to develop the predictor model. The results indicate that factors such as location, school type, and project duration significantly predict both the schedule performance and managerial and organizational difficulties in school construction. An indirect correlation, rather than a direct association, was found between schedule performance and managerial and organizational difficulties. The proposed model will be a helpful guide for construction professionals, engineering managers and government decision-makers seeking to improve the performance of "design-bid-build" school construction projects. We suggest integrating the qualification-based selection (QBS) system into traditional procurement methods for public investments.

Effects of low clay content on the anisotropic behavior of sand-clay mixtures: laboratory investigation using TSHCA

2024-02-20T09:52:29+00:00

Undrained behavior of sandy soil with fines content is a challenge in geotechnical research. In this article, the effect of low clay content (plastic Kaolin) on the anisotropic behavior of sand is studied. In the technical literature, there are different data about the effect of fine particles (generally high percentage), but there are not enough studies on low fines content (especially plastic fines) and anisotropic conditions. For this purpose, 30 undrained tests are performed using a torsional shear hollow cylindrical apparatus (TSHCA) with constant (α^o) and (b) values on Firoozkuh sand. The specimens had Kaolin contents of 0, 3, 5, 7 and 10%, and the inclination angle (α^o) is varied from 15^o to 60^o. The specimens are prepared by dry deposition method and are consolidated under P'c= 100 and 200 kPa. The results of the experiments show that increasing the (α^o) leads to more contractive behavior in sand. By adding clay particles to the host sand up to 3%, the peak strength of the specimen is increased (7% and 6% for α=15°and 30°, respectively), and then with the increase of clay content up to 10%, the strength of the specimen is decreased (33% and 22% for α=15°and 30°, respectively). But at α = 60^o, with the addition of 5% clay, decrease in the peak strength is observed (about 15%) and with a further increase in the clay content, unlike the angles of 15^o and 30^o, increase in the peak strength of the specimen is observed, so that at 10% clay, the strength of the specimen is higher than the host sand (about 7%), which can be attributed to the cohesion nature of the clay particles. With the increase of clay content, anisotropy degree is decreased. In other words, with the increase of fines content, the anisotropic behavior is decreased.

Investigation of the earthquake behavior of the historical Adana great clock tower using FEM updated based on environmental vibration data

2024-02-07T11:04:50+00:00

In this study, the historical Adana great clock tower's dynamic characteristics (natural frequencies and mode shapes) were determined using the operational modal analysis (OMA) method. The finite element model (FEM) of the Clock Tower was updated based on the experimentally obtained dynamic characteristics. The update process was performed manually using the material properties of the Clock Tower. Linear dynamic analyses of the structures under earthquake loadings were performed using its updated finite element model. The acceleration records of the 1998 Adana-Ceyhan earthquake, scaled according to the horizontal elastic design spectrum defined in TBEC (2018) were used for dynamic input. The displacements, maximum and minimum principal stresses of the Clock Tower were obtained and evaluated. As a result of the analyses, it was determined that there was a potential for damage to the Clock Tower due to exceeding the tensile strength of the walls, but the potential for damage to the Clock Tower due to exceeding the compressive strength of the walls is weak.

Strengthening of flexural behavior of reinforced concrete beams by using hybrid fibers: experimental and analytical study

2024-02-08T01:20:27+00:00

The research investigates the flexural behavior of reinforced concrete (RC) beams by incorporating hybrid fibers (a combination of glass and steel fibers). Ten specimens measuring 150 mm x 200 mm x 1500 mm were cast and tested under two-point loading. The specimens were divided into three groups, each containing three specimens. Additionally, a control specimen was examined. Comparing the strength performance of each group to the control specimen revealed that the hybrid fiber-reinforced beams exhibited increased strength. The optimal hybrid fiber composition was 0.4% steel and 0.2% glass fiber. Similarly, the optimal steel and glass fiber percentages were both 0.4%. Experimental results showed that the load-carrying capacity improved significantly: 28.80% with glass fiber, 63.74% with steel fiber, and 79.23% with hybrid fiber compared to conventional RC beams. The study evaluated load-carrying capacity, load deflection, ductility, stiffness, and failure modes of RC beams. An analytical study using finite element modelling was conducted, and the analytical results were compared to experimental findings. Fundamental statistical values included mean, standard deviation, and coefficient of variation for load and deflection. Finite element analysis (FEA) was employed to predict experimental outcomes, and the analytical results closely correlated with experimental data. The load mean, standard deviation and coefficient of variation were 0.98, 0.01, and 0.56, respectively. The deflection exhibited corresponding values of 0.97, 0.01, and 1.41. The graphical abstract of the present study is displayed in Figure 1.

Evaluation of mechanical characteristics of high strength steel fiber reinforced concrete with various concrete strengths

2024-02-27T18:48:16+00:00

The performance of concrete is robust in compression but lacks tensile strength, making it brittle. Steel fibres are added to enhance concrete properties. These fibres play a crucial role in construction by improving structural performance, preventing cracks, and increasing ductility. The study investigated high-strength steel fibre-reinforced concrete (HSSFRC) with varying concrete strengths. Three high-strength concrete grades (70 MPa, 80 MPa, and 90 MPa) and different water-cement ratios (WCR) (0.25, 0.30, and 0.35) were studied. Hooked-ended 50mm steel fibres were added at content levels of 0.25%, 0.50%, 0.75%, and 1.00%. As steel fibre content increased from 0.25% to 0.75%, the compressive strength (CS) improved by 3.37%, 7.29%, and 10.54%. At the same time, the split tensile strength (STS) increased by 20.86%, 24.07%, and 26.74%. Similarly, the flexural strength (FS) increased by 19.87%, 23.12%, and 25.82% for a WCR of 0.25 in 70 MPa grade of concrete. However, adding 1.0% steel fibre led to decreased mechanical properties. The optimal steel fibre content across all concrete mixes was 0.75%. Mechanical properties weakened with higher WCR (0.25, 0.30, and 0.35). Additionally, regression analysis explored the relationships between CS, STS, and FS in the concrete mixes. The comparison between the test results and the regression analysis was carried out alongside the previous empirical formulas. Remarkably, the empirical formulas exhibited strong alignment with the experimental findings.

Prediction of mechanical properties of high strength steel fibre reinforced concrete using linear regression techniques

2024-02-27T18:42:58+00:00

In this study, researchers investigated the mechanical properties of high-strength steel fiber-reinforced concrete (HSFRC). The experimental study involved evaluating high strength concrete (HSC) using various steel fibre contents (ranging from 0.25% to 2.00%) and different water-cement ratios (WCR) (0.25, 0.30, 0.35, and 0.40). Adding 1.50% steel fibre to HSC led to an increase in compressive strength (CS). Specifically, the CS improved by 13.42% to 15.19% for WCR of 0.25, 0.30, 0.35, and 0.40. Including 1.50% steel fibre enhances split tensile strength (STS). The STS increased by 25.89% to 32.62% for the same WCR. High-strength concrete with 1.50% steel fiber exhibited improved flexural strength (FS). The FS rose 29.00% to 35.07% for the specified water-cement ratios. The study also considered the modulus of elasticity (ME) at 28 days. Interestingly, the strength of HSC decreased as the WCR increased. Lower WCR generally contributed to better mechanical properties. The experimental results were compared with linear regression analysis and existing empirical formulas. The regression analysis demonstrated good agreement with the experimental findings. Overall, the optimal steel fibre content was 1.50% across all WCR, significantly improving mechanical properties. The study provides valuable insights for designing HSC with enhanced performance.

Sustainable and strength-enhanced concrete using microbial consortia

2024-02-09T01:52:33+00:00

The mechanical properties of concrete were examined by using steel fibres and two types of bacteria (Pseudomonas otitidis and Bacillus cereus). These steel fibres and bacteria were incorporated into the concrete mix in proportion to the weight of the cement. To ensure the resilience of microbial consortia incorporated into bio-concrete against the mechanical and chemical stresses encountered during concrete production, these microorganisms should exhibit critical characteristics, including robust alkali resistance and the ability to produce endospores. By employing 16S rRNA gene sequencing, we verified the identity of a group of organisms isolated from fermented lime mortar and curing construction water. Microbiologically induced calcite precipitation (MICP) was confirmed through microstructural analyses using techniques such as scanning electron microscope (SEM) and x-ray diffraction (XRD). The concrete was prepared with optimal concentrations of cultured bacteria (ranging from 10³, 10⁵ and 10⁷ cells/ml), and steel fibres were added to the concrete at varying percentages (0%, 1%, 1.5%, and 2%). The optimal steel fibre content was 1.5%, and its strength properties were compared to conventional concrete. Notably, when Pseudomonas otitidis and Bacillus cereus bacteria were added to the traditional and optimal concrete mix, the compressive strength was significantly enhanced compared to the conventional concrete mix.

Effect of silica fume on the microstructural and mechanical properties of concrete made with 100% recycled aggregates

2024-03-05T13:18:50+00:00

Recycled concrete aggregate can be utilized in structural concrete in order to reduce the use of natural resources and the harmful impacts of waste concrete on the environment. This present research aimed to assess the effectiveness of using recycled aggregate concrete with the partial replacement of cement by silica fume (SF) to analyze the microstructural and mechanical properties of recycled aggregate concrete (RAC). In this study, recycled stone was used as coarse aggregate. The main variables of the study included the dosage of silica fume that was employed as a partial replacement of ordinary Portland cement (OPC) with four different percentages: 4%, 8%, 12%, and 16% by weight. Five different mixes were prepared, with four mixes created by varying amounts of silica fume, which were designated as RSACSF4, RSACSF8, RSACSF12, and RSACSF16. The other mix was created as a reference mix without silica fume and designated RSACSF0. Slump test was conducted to investigate the workability of concrete mixes. From the test result, a decreasing trend was found after adding more percentage of SF. Compressive and splitting tensile tests were conducted to analyze the mechanical properties of RSAC at 7 and 28 days. The results showed that the addition of SF improved the performance of RSAC at early and later curing ages, and a 12% addition of SF showed the best result. Scanning electron microscopy and X-ray diffraction analysis were performed to explore SF's microstructural performance and effect on RSAC. The results showed that silica fume showed a positive pozzolanic impact, and when combined with calcium hydroxide, it underwent a secondary hydration reaction that boosted the generation of calcium silicate hydrate and improved the parameters of the interface transition zone. X-ray diffraction analysis showed that silica fume and silica fume have similar pattern intensities. Finally, 12% SF is recommended as a partial replacement for cement in RSAC.

Properties of self-curing and self-cooling eco-friendly novel green cement-based mortar

2023-12-20T09:56:51+00:00

In this study, mullein plant (MP) (Verbascum Thapsus) was replaced with cement at a dosage of 300 (the amount of cement in mortar for producing 1 m³ mortar) in cement-based mortars at different weight ratios (0%, 1.5%, 3%, 4.5% and 6%). To investigate the impact of MP on the hydration (internal) temperature and the formation time of hydration products in mortars, the mortars' interior temperature and moisture ratios were measured and recorded every minute for one day. It was concluded that the MP had a high-water absorption capacity and delayed the initial and final setting times. The optimum ratio of MP as a replacement for cement was found to be 1.5%. The study also investigated the effects of direct current (DC) application on fresh mortars (both with and without MP). The results showed that the 7-day mechanical strength of the reference mortars exhibited a significant increase with the application of DC. Previous studies have not explored the use of MP in cementitious composite materials. This study concluded that adding a specific amount of MP to cement-based materials can provide self-curing and self-cooling properties. This research is critical for water conservation as it develops a novel self-curing method.