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Rice straw waste, among other issues, is a significant source of air pollution and methane emissions from biological decomposition. This study examines the use of Rice Straw Ash (RSA), when combined with Fly Ash (FA) and Laterite Soil (LS), as a pozzolan in cementitious systems. The study's purpose is to examine the microstructure and compressive strength of a geopolymer mortar composed of FA, RSA, and LS. The RSA is activated with sodium hydroxide (NaOH), an alkaline activator, with concentrations of 6, 12, and 15 M NaOH. After air and water curing for 3, 7, and 28 days, the compression strength of the geopolymer mortar was tested. To determine the dominant compound of the pozzolan reactions that were generated in cementitious systems, Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) were employed. When geopolymer mortar is cured in air and water, its compressive strength increases with age. This is due to the fact that RSA, FA, and LS have the ability to form iron oxide (Fe3O4) in the amorphous phase and have a strong bond with alumina (Al2O3) and silica (SiO2). The material's fineness affects its compressive strength as well. This study intends to replace cement in mortar and concrete utilizing environmentally friendly materials. Furthermore, the creation of geopolymer material usually requires the use of oven heat to enhance the geopolymerization procedure. However, this study shows that this method does not require oven heat. [ABSTRACT FROM AUTHOR]

This study evaluates the physical and mechanical properties of Abaca Fiber Reinforced Polymer (AbFRP) laminates for sustainable structural application. The research examines the impact of alkali treatment on the weight and diameter of the abaca fibers, as well as the tensile strength of both individual fibers and AbFRP laminates. The results indicate that the application of 0.5 wt% NaOH treatment reduced the weight and diameter of abaca fibers by 5.7% and 4.2%, respectively. Alkali treatment enhanced the tensile strength of single fibers, increasing it from 977.8 MPa to 1978.6 MPa, while the tensile strength of AbFRP laminates decreased from 78.1 MPa to 67.3 MPa. In terms of elastic modulus, the untreated and treated AbFRP laminates exhibited values of 14.9 GPa and 18.5 GPa, respectively. These findings demonstrate that AbFRP laminates possess notable mechanical characteristics, making them suitable for implementation for structural application. [ABSTRACT FROM AUTHOR]

Strengthening of Reinforced Concrete (RC) beams using GFRP to increase flexural capacity often fails due to premature debonding and delamination of old concrete joints and grouting. The current research introduces a method of repairing and strengthening RC beams using grouting mortar, dyna-bold anchors, and Glass composite FRP (GFRP) sheets. Dyna-bold anchors are used as shear connectors between the old concrete and the grouting. In this research, 10 RC beams measuring 150 mm x 200 mm x 3300 mm, consisting of 2 control specimens (BK), 4 GFRP strengthening beams, and 4 GFRP strengthening beams with dyna-bolt anchors, were tested. The results show that the use of dyna-bold anchors in the joints between old concrete and grouting can increase the bending and shear capacity of the beam by 44.70%, indicating that the addition of dyna-bold anchors is able to prevent premature cracking along the joints and increase the stiffness and flexural capacity of the RC beams. These findings have significant practical implications for the repairing and strengthening of RC beams in real-world applications. [ABSTRACT FROM AUTHOR]

Indonesia experiences frequent earthquakes due to its proximity to seismic faults. Many one- or two-story residential buildings with reinforced concrete frames filled with masonry are severely damaged during moderate to high-magnitude earthquakes. One solution to reduce seismic loads on the structures is the use of Cellular Lightweight Concrete (CLC). The behavior of CLC block panels as an infill wall against lateral cyclic loading is the subject of this experimental investigation. The specimens consist of two Reinforced Concrete (RC) frame models: a CLC block panel used as an infill wall for the RC frame (DB-2) and a reinforced concrete frame (DB-1). This research uses displacement control methods and lateral cyclic loading to evaluate the behavior of wall structures according to the ASTM E2126-02a. The results showed that the strength value of the DB-2 specimen was 29.61% higher than that of the DB-1 specimen. Neither loading nor unloading of the DB-2 specimen caused a decrease in relative stiffness, unlike the DB-1 specimen. This indicates that the DB-2 specimen does not experience a squeezing effect and instead becomes more stable and has improved energy dissipation without losing strength. The results show that bricks, concrete blocks, and other fillers can be replaced with precast CLC panels for reinforced concrete frame walls. [ABSTRACT FROM AUTHOR]

Steel dampers are components used in building structures to reduce vibration and energy generated by dynamic loads such as earthquakes. Several factors affect the effectiveness of steel dampers in reducing energy, including the cross-sectional area, mass distribution, cross-sectional geometry, and material stiffness. The cross-sectional geometry or shape of the steel damper can affect how energy is absorbed and dissipated in the structural system. Cross sections with different geometric variations can have different mechanical responses to dynamic loads. This study aims to analyze which type of steel damper is effective in terms of stiffness and damping capacity against lateral cyclic loads. The steel damper cross-sectional variations used are slit steel dampers (SSDs), tapered steel dampers (TSDs), and oval steel dampers (OSDs). Cyclic testing of the dampers used displacement control with the same target deviation for all three damper types. The results showed that the stress and strain distributions of the oval steel damper were more even than those of the other two models. The variations in the energy dissipation capacities of the three cross-section variations are relatively the same. However, the slit steel damper type has the best stiffness compared to the other two types. This research is ultimately expected to influence the science of the structure of a building in preventing and anticipating earthquakes or other disasters. [ABSTRACT FROM AUTHOR]

Corrosion of steel reinforcement from chloride exposure can compromise the strength of reinforced concrete structures. Rust formation expands, applying pressure on concrete, resulting in cracks and spalling. Prompt repair is crucial for severe cases of spalling. This research assessed the efficacy of repair strategies for reinforced concrete beams post-spalling, including grouting and different techniques involving Glass Fiber Reinforced Polymer (GFRP) reinforcement. The research examined four variations of reinforced concrete beams, each sized at 150 mm × 200 mm × 3300 mm. Results showed that the standard beam (BK) had an average maximum load capacity of 29.74 kN. In contrast, the grouted beam (BGR) demonstrated a reduced maximum load of 14.39 kN, along with decreased steel and concrete strain compared to BK. This suggests that the grouting repair did not fully restore the beam's flexural capacity after spalling. Incorporating GFRP strips (BGRS) led to a marginal increase in the beam's maximum load, albeit remaining below BK, with lower steel and concrete strain than BK. However, the steel and concrete approached their yield points, indicating enhanced flexural performance. The full-wrap GFRP beam (BGRSF) experienced an 8.08% increase in maximum load compared to BK, with concrete strain surpassing BK, suggesting an enhancement in flexural stiffness. [ABSTRACT FROM AUTHOR]

The Sulawesi region is located at the confluence of a smaller Philippine plate and three major global plates, namely the Indo-Australian, Pacific, and Eurasian. This strategic location makes Sulawesi and the surrounding earthquake-prone region in Indonesia. Recognizing the seismic vulnerability of this region, various measures, such as the use of houses on stilts, have been explored to enhance earthquake resistance. These structures are designed to avoid direct exposure to seismic energy, according to several reports on Indonesian earthquakes. In the last two years, an in-depth investigation has been carried out to analyze the behavior and resistance of Bugis Traditional Houses to earthquakes. Although simulation and computational studies are still in progress, the results show that Bugis-Makassar House on stilts maintains an elastic state with a high level of performance. Therefore, this study aimed to investigate the mechanical behavior of Bugis-Makassar stilt house structures using full-scale tests. During the investigation, experimental testing was conducted using house specimens measuring 1.5×2.3 m in the laboratory. A cyclic lateral loading analysis was performed using ISO 16670-2003 as a guide. The results showed that cyclic lateral loads caused house structures to sway, while the timber experienced minimal damage. Both the hysteresis energy, EH to EI, and the energy conversion ratio, GPE to ESE (ER), were found to be approximately balanced. This equilibrium suggested that seismic energy can be cyclically stored and released to reduce damage to structural elements. [ABSTRACT FROM AUTHOR]

One of the common causes of damage to the concrete structures close to the sea line is corrosion on the steel reinforcement in the concrete, which may cause spalling on the concrete cover. This paper presents the results of the simulation of the corroded reinforced concrete beams, which were repaired using the grouting method and FRP strengthening. The concrete cover of the beam specimens on the tensile side was filled with grouted concrete instead of filled with normal concrete to simulate the repair of concrete spalling. Three types of beam specimens were prepared and tested under a monotonic loading. BG and BPF were the specimens for beams with grouting only and beams with grouting and flexural strengthening using FRP sheets, respectively. Flexural strengthening using FRP sheets was carried out to restore the flexural capacity. As a comparison, control beams were also prepared in the form of normal reinforced concrete (BN). The results showed that the BG beam had a capacity of only about 50% compared to the control beam (BN). However, applying flexural strengthening using FRP sheet as on the type BGF beams showed that it had approximately the same capacity as BN specimens. This indicated that the repair method using grouting on damaged concrete covers and strengthening using FRP sheets was an effective alternative to repairing the corroded reinforced concrete beams. [ABSTRACT FROM AUTHOR]

Reinforced concrete beams must meet strength and durability standards, but aggressive environmental factors are the main cause of corrosion, which can affect the strength and durability of building structures. Maintenance, retrofitting, and reinforcement of structures are important to ensure safety. It is necessary to take appropriate measures to address corrosion problems in building structures early on. One way to achieve this is by repairing damaged structures using more modern and effective technologies and materials. This study aims to determine the flexural behavior of reinforced concrete (RC) beams repaired with Sikagrout-215 material and reinforced with GFRP sheets with different layer configurations. The study used three RC beams as the control group, three RC beams coated with Sikagrout-215 mortar, and six RC beams reinforced with GFRP. All beams were subjected to 4-point bending tests to determine their load capacity, crack response, ductility, and energy absorption capacity. The results showed that repair with grouting decreased the load capacity, while reinforcement with a combination of mortar grouting and GFRP increased the maximum load. Reinforcement of the support region could restore the function of the beam by 9.3%. Among the three types of reinforcement, BGRST significantly improved the first crack response, yield response, and ultimate performance of the RC beams. Beam fracture occurred more frequently with Sikagrout-215 mortar reinforcement, while reinforcement with GFRP composites partially protected the load capacity after fracture. [ABSTRACT FROM AUTHOR]

The purpose of this study was to understand the deflection behavior of reinforced concrete beams using GFRP bar as flexural reinforcement and GFRP sheet as shear reinforcement. The tested beams with dimensions of span length were 3000 mm, width of 150 mm and height of 250 mm of concrete quality f'c.25 MPa. The beams use GFRP bar 3D13 as flexural reinforcement and U-wrap GFRP sheet 50 mm wide with a distance of 100 mm. U-wrap GFRP sheet shear reinforcement is only installed in shear spans. The beam is loaded with two concentrated loads monotonically until it collapses. The test results show that the loaddeflection relationship of GFRP bar reinforced concrete beams with external shear reinforcement of U-wrap GFRP sheet shows two linear curve patterns. The results of the analysis show that the ACI-440.1R-06 approximation equation can be used to accurately predict the deflection in the middle of the GFRP bar reinforced concrete beam with external shear reinforcement from U-wrap GFRP sheet.

An experimental study was undertaken to examine the behavior of RC-frames employing precast foam concrete reinforced with diagonal CFRP as an infill wall under ASTM E2126-02a cycle testing methodology (ASTM 2003) in order to anticipate the onset of earthquake-related disasters. The study aimed to determine the failure rate and mechanism based on FEMA 356. An RC frame with precast foam concrete acting as an infill wall without retrofitting (WTI) and an RC frame with precast foam concrete acting as an infill wall and CFRP retrofitting at a width of 36 cm (WTC) were constructed as two different types of examples. The results showed that whereas the WTI produced a maximum load value of 44.88 kN at push loading and 52.30 kN at pull loading, the WTC produced a maximum load value of 102.87 kN at push loading and 80.09 kN at pull loading. The diagonal CFRP retrofitting increased the RC frame's capacity to support in-plane horizontal cyclic stresses when foam concrete precast was used as an infill wall. The test specimen with the CFRP retrofitting underwent a shear failure that started with the CFRP strip debonding and ended with a shear structural collapse. The infill wall had an in-plane failure and a diagonal crack with shear collapse. This demonstrates that the maximum load that the RC specimen could withstand after being retrofitted with CFRP rose for each structural performance grade. [ABSTRACT FROM AUTHOR]

Pavement recycling is an appropriate technology for constructing and restoring road pavement structures due to the limited supply and high cost of pavement materials. This study aims to improve the recycled mix's performance by replacing the fine aggregate in the recycled mix for road pavement with Buton Granular Asphalt (BGA). The percentage of recycled material (Reclaimed Asphalt Pavement/RAP) in the mixture was limited to 20% and 30% by weight of the total mixture. BGA was added by 3%, 6%, and 9% in each mixture with the RAP variation. Mixture performance was obtained through Indirect Tensile Strength (ITS) testing. The ITS test results showed that the ITS value of the mixture with RAP and BGA increased by an average of 4.7-15% compared to the mixture without RAP and BGA. The Toughness Index (TI) value increased by 3.5-19.8% with the addition of RAP. With the addition of 3% BGA, the TI value tends to increase and subsequently decrease up to 9% BGA levels. The result indicated that adding 30% RAP and 3% BGA to the mixtures improved pavement performance and could be a solution to increase the elasticity and fracture resistance of the mixture. [ABSTRACT FROM AUTHOR]

Experimental and analytical studies on the behavior of interface between old and new deck slabs were investigated in this study. The test was performed to represent a bridge widening method that has been developed in Japan. Therefore, each specimen consist of the old and new deck slabs. The connection between those deck slabs was varied into a rough and smooth surface. Before testing, the slabs were prestressed using unbonded PC rods which amount of 1.0 MPa. The result of this study indicated that the difference in the level of roughness does not provide a significant effect on the ultimate capacity. Remarkable effects were only observed on crack pattern, deflection, and joint opening behavior. To validate the experiments, the ultimate capacity of experiment was compared with the predicted shear capacity obtained from JSCE Specification and fib Model Code. In the guidelines, the area of the interface is assumed as the total area of the interface. However, such assumption cannot be used in this study. Therefore, the effective area of the interface obtained from FEM analysis was proposed in this study. Eventually, by using the proposed effective area of the interface, the calculated results showed that all guidelines provide a good lower limit to predict the ultimate capacity of the deck slabs.

Pre-stressed concrete (PC) sheet piles are commonly used for river revetment, retaining wall, etc. However, it has not been used in port and harbor structure due to corrosive environmental conditions, which is severe for steel corrosion in concrete structure. Performances of PC sheet piles were evaluated after 12 years exposure in the marine splash environment. An evaluation of mechanical properties, carbonation depth, porosity, chloride content and PC steel condition were carried out. Overall, all specimens showed satisfactory performance: only a few concrete corner and edge chips, low chloride content and low rate of corrosion were observed. Investigation results indicated that BS5 (B = GGBFS, S = steam curing, and cover thickness of 5 cm) showed the best performance (more durable), even though its strength was lower than the other.

Nowadays, castellated beam becomes popular in building structural as beam members. This is due to several advantages of castellated beam such as increased depth without any additional mass, passing the underfloor service ducts without changing of story elevation. However, the presence of holes can develop various local effects such as local buckling, lateral torsional buckling caused by compression force at the flange section of the steel beam. Many studies have investigated the failure mechanism of castellated beam and one technique which can prevent the beam fall into local failure is the use of reinforced concrete slab as lateral support on castellated beam, so called composite castellated beam. Besides of preventing the local failure of castellated beam, the concrete slab can increase the plasticity moment of the composite castellated beam section which can deliver into increasing the ultimate load of the beam. The aim of this numerical studies of composite castellated beam on certain loading condition (monotonic quasi-static loading). ABAQUS was used for finite element modelling purpose and compared with the experimental test for checking the reliability of the model. The result shows that the ultimate load of the composite castellated beam reached 6.24 times than the ultimate load of the solid I beam and 1.2 times compared the composite beam.

This paper presents reduced beam section (RBS) technique on castellated beam. Aim of this study is to ensure the plastic moment reach far from column face without significant of strength decreasing. Four models of castellated beam with various types of RBS and one model without RBS have been considered. ABAQUS FEA software package was used for modelling purpose. Loading condition, i.e. lateral load as representing earthquake load, was monotonic load using displacement control at the top of the column. The result shows that the maximum load and the maximum displacement with RBS and without RBS do not portray significant difference. The maximum load RBS castellated beam and without RBS were respectively 86.17 kN and 80.63 kN. It is indicated that the RBS on castellated beam might share relatively similar maximum load compared to non RBS castellated beam and the RBS can secure the stress concentration and plastic moment, the location of which is far from the column face. The reduced beam section (RBS) is put on beam-to-column moment connected on castellated beam.

Six prestressed concrete beams (PC beam) were used for evaluation, consist of four post-tension beams (PC-O) and two pre-tension beams (PC-R). In order to investigate the effect of crack on prestress loss and bending capacity after long-term exposed, prestressed concrete beams were pre-crack and then exposed to marine environment. Experimental work was carried out to evaluate PC beams performance after long-term exposed. In addition, visual observations and load bearing capacity test was carried out. Furthermore, evaluation of prestress loss conducted using three-point loading bending test and the remaining tendon forces in the beam were determined using Crack Re-opening Method. The experimental results revealed that prestress loss was increased due to corrosion of strand/wire which affected by the pre-crack on the prestressed beams. Approximately a prestress loss around 26% and 30% was recorded for post-tension and pre-tension beams respectively.

Many areas of Indonesia are located near earthquake faults, resulting in the recurrence of earthquake phenomena in various regions of Indonesia. This research is an experimental study on the behavior of prefabricated foam concrete as wall infill material under lateral cyclic loading. This study analyzed the relationship between load and displacement in prefabricated foam concrete as an infill wall. The test object consisted of 2 wall models: reinforced concrete frames (DB 1) and prefabricated foam concrete infill wall (DB 2). Lateral cyclic loading with displacement control method is carried out to evaluate the structural behavior of the wall regarding ASTM E2126-02a. The test results showed that the strength value of the DB 2 specimen resulted in a 29.61% increase of strength than the DB 1 specimen. Furthermore, the relative stiffness degradation on both specimens is not too significant in both the loaded and unloaded state, so there may be no pinching effect. It’s more likely to lead to a more stable condition with higher energy dissipation capability without decreasing the strength of the specimen when compared to the DB 1 specimen. Therefore, foam concrete precast panel can be utilized as an alternative infill material for walls on a reinforced concrete frame structure to be replaced with clay bricks, hebel, batako, etc [ABSTRACT FROM AUTHOR]

Waste materials are often used in brick manufacturing to develop a sustainable building material and reduce the consumption of natural clay resources. In this study, palm oil fuel ash (POFA), a waste generated from the palm oil industry, was used in brick production as clay replacement at dosages of 5, 10, 15 and 20% by weight. The brick specimens were produced in a local factory to study the feasibility of manufacturing bricks containing POFA under real industrial production conditions and their properties were compared with conventional bricks (0% POFA). The results show that a lighter brick is produced when mixed with POFA but the flexural and compressive strength decreased. Water absorption and initial rate of absorption increased when clay is mixed with POFA due to the presence of a more porous structure than conventional bricks. Further, brick specimens containing POFA had a higher resistance to the formation of efflorescence than conventional bricks; however, their resistance was poor when subjected to sulphate attack. The findings of this study suggest that up to 5% POFA can be used as clay replacement for bricks produced in a local brick kiln industry to meet the current international standards for conventional bricks. [ABSTRACT FROM AUTHOR]