Construction Technologies and Architecture Vol. 18

Abstract: This paper presents effect of low contents graphene oxide (GO) on the properties of cement mortar that could be developed for nano modification in cement composites. The characteristic of GO-cement mortars were first evaluated using slump flow test. Then, mechanical properties of GO-cement mortars were carried out. Specimens were made on a 5×5×5 cm³ cube mold with five different contents of GO (e.g., 0.01% to 0.05 %) using a water to cement (w/c) ratio of 0.485. The compressive strength tests were performed at specimen age of 3, 7, and 28 days. Results showed that the incorporation of GO significantly improved mechanical properties of GO-cement mortars. Further, the obtained compressive strength of mortars significantly increased and achieved the highest 28 day-strength by 63.6% at 0.04% GO.

Abstract: Geopolymers offer a sustainable alternative to reduce reliance on Portland cement in construction. This study examines coal fly ash and rice husk ash as potential substitutes in geopolymer formulations. Microstructural tests, including chemical composition analysis (SNI 2049-3-2022), Density (SNI 1964-2008), FTIR, and SEM-EDS, were conducted to evaluate their properties. Chemical analysis showed that coal fly ash contains 90.55% silica (SiO₂) and less than 10% calcium oxide (CaO), categorizing it as Class F fly ash, while rice husk ash has 50.86% SiO₂ and 38.41% CaO, both comparable to cement. FTIR confirmed hydroxyl group presence through O-H stretching, while SEM-EDS revealed elements like silicon, aluminum, calcium, and metallic oxides, consistent with their surface morphology. The results demonstrate that coal fly ash and rice husk ash meet the pozzolanic element requirements necessary for geopolymer formation. Their chemical composition, supported by FTIR and SEM-EDS findings, highlights their potential as alternative cement substitutes in sustainable construction.

Abstract: Indonesia is a tropical country with high rainfall, which necessitates pavement with higher void content and good drainage conditions. The quality of road pavement depends on the materials used. One type of asphalt mixture with high void content and permeability but low stability is porous asphalt. This is due to the composition of porous asphalt, which consists predominantly of coarse aggregates compared to fine aggregates. This study utilizes waste tires, Low-Density Polyethylene (LDPE), gilsonite, and 60/70 penetration asphalt as binders, referred to as modified asphalt, in porous asphalt mixtures. The objective of this study is to determine the Optimum Asphalt Content (OAC) using waste tires, LDPE, gilsonite, and 60/70 penetration asphalt as binders in porous asphalt mixtures and to compare it with the OAC of conventional asphalt. The method used in this research is based on the Australian Asphalt Pavement Association (AAPA) (2004) method, employing open-graded porous asphalt with a maximum aggregate size of 14 mm. According to AAPA (2004), OAC determination requires three parameters: Cantabro Loss (CL), Asphalt Flow Down (AFD), and Voids in Mix (VIM). The study began with testing the physical properties of aggregates and asphalt, both conventional and modified. After testing the physical properties, the next step was determining the optimum asphalt content. The OAC obtained for porous asphalt mixtures using modified asphalt as a binder was 5.3%, while the OAC for conventional asphalt was 5.75%, serving as a comparison.

Abstract: Rigid pavement is a type of pavement that uses cement as the main binding material and has a high level of stiffness. The prolonged use of cement has increasingly negative impacts on the environment. Using geopolymer as a substitute for cement can be an eco-friendly alternative solution. Geopolymer is an environmentally friendly material that can be developed as an alternative to cement concrete in the future. The purpose of this study is to determine the compressive strength of geopolymer concrete using rice husk ash and shell as fine aggregates in rigid pavement. The research method used is experimental. The method used for mix design calculation is AASHTO 1993, by making 8 test specimens. Each test specimen uses 4 aggregate and binder ratios, which are 75:25, 70:30, 65:35, and 75:25, each with 2 alkaline activator ratios, which are 3:1 and 5:2. The compressive strength testing of the specimens was conducted at 28 days. The concrete quality used, K225, is equivalent to 18.68 MPa. The compressive strength testing of geopolymer concrete achieved optimum compressive strength at a variation of 65:35 aggregate, 3:1 alkaline, 5% rice husk ash, and 5% shell, which was 18.9667 MPa. At the variation of 75:25 aggregate, 3:1 alkaline, 5% shell, the highest value was 21.4013 MPa. Based on the type of concrete according to its compressive strength, geopolymer concrete with fly ash, rice husk ash, and shell is classified as normal concrete because its compressive strength exceeds 15 MPa and can be a substitute for cement with relatively low strength.

Abstract: Syzygium cumini is a plant belonging to the Myrtaceae family and is widely used in medicine and food. However, its application in the engineering field is still very minimal, particularly as an anti-corrosion material. There are also limited studies on the quantitative screening of phytochemical and bioactivity of S. cumini. Therefore, this study aims to analyze the chemical compounds of S. cumini fruit as a corrosion inhibitor as well as determine total tannin (TTC) and flavonoid (TFC) content. The extraction process was carried out with a soxhlet extractor using 96% ethanol solvent. Characterization was then conducted using FTIR (Fourier Transfer Infrared) test and total antioxidant test with a UV-Vis spectrophotometer. Spectrum analysis showed the presence of Hydroxyl (O-H), Alkane (C-H), Carbonyl (C=O), Aromatic Ether (C-O), and Amine (C-N) functional groups. The results also revealed that TTC was 26.83% higher, while TFC was 2.11%. In addition, S. cumini fruit was reported to contain high functional groups and antioxidant compounds, which were useful as active molecular inhibitor ingredients.

Abstract: Erosion and sedimentation generally occur in river channels. Erosion impacts reducing the walls and bottom of the channel due to shear stress between the moving fluid particles and the channel particles. Sedimentation causes a buildup of sediment particles resulting from erosion in an area of the river which results in shallowing. In efforts to overcome erosion on river walls, especially at river bends, the river “groynes” is usually used. In this research, we tested the effectiveness of river “groynes” spacing in reducing erosion on river walls. We carried out numerical simulations to prove the effectiveness of river “groynes” in reducing flow velocity. Based on the results of this research, it is proven that with the presence of a river “groynes”, there is a decrease in flow velocity on the river wall where the river “groynes” are installed. The closer or smaller the distance between the river “groynes”, the smaller the impact of erosion that will occur.

Abstract: Central Java is one of the provinces in Indonesia having the largest potential for wind energy consumption with a potential of 8.56 Gigawatts. The development of wind energy through the construction of Offshore Wind Turbines (OWT) can supply the demand for power consumption in Central Java. The monopile is the most adopted foundation concept for the sea depths of less than 40m. This study aims to design an optimum monopile foundation to support the wind turbine structure and to evaluate the stability of the foundation based on a combination of extreme wind and extreme wave conditions. The design is based on the criteria of deflection and rotation requirements. The analysis was conducted in consideration of variations in the diameter, thickness and embedded length of the monopile. The soil layers in the studied area consist of very soft clay to very stiff clay. Monopile foundation is designed based on design criteria according to limit state design, namely ultimate limit state (ULS), Serviceability Limit State (SLS) and Fatigue Limit State (FLS). It was obtained the diameter, thickness, and embedded length of the monopile about 3.25m, 0.042m, and 52.8m. The embedded length and diameter have significant contribution to the bearing capacity and reduce the magnitude of deflection and rotation monopile.

Abstract: This study evaluates the accuracy of satellite gravity methods in disaster risk mapping for the coal mining areas of West Coast Aceh, specifically between longitudes 96.00°E to 96.30°E and latitudes 4.00° to 4.30°. The satellite gravity technique was utilized to detect fault zones through the examination of rock density variations. The collected data was processed to determine the complete Bouguer anomaly, including terrain corrections based on an initial average density of 2.67 g/cm³. The complete Bouguer anomaly values span from -36.2 mGal to 42.4 mGal, with higher values concentrated in the northeastern region and lower values noted in the southwestern coastal area. Regional and residual anomalies were distinguished through first-order trend surface analysis, resulting in residual anomalies between -33.1 mGal and 32.9 mGal. Gradient analysis was utilized to define geological boundaries, which were confirmed with geological maps. The horizontal derivative results exhibited an intense connection with fault structures found on the reference geological map, whereas the vertical derivative predominantly emphasized major fault boundaries but was less effective in identifying smaller structures. The results of this study are anticipated to substantially enhance disaster risk reduction initiatives and facilitate safer, more sustainable development planning in the West Coast Aceh region. Furthermore, these findings serve as a significant reference upcoming research and decision-making concerning disaster mitigation in mining regions.

Abstract: This research is against the backdrop of the frequent occurrence of recurring floods in urban drainage channels in the Meulaboh City area. The locations of the observation areas are Kuta Padang Village, Ujong Baroh Village, and Drien Rampak Village in Johan Pahlawan District, West Aceh Regency because this area has several flood and inundation problems at several observation points. The purpose of this study is to analyze and evaluate the existing condition of drainage channels in the study area and seek solutions to minimize inundation and flooding or zero runoff. The research method used is descriptive quantitative and starts from field surveys, data collection, hydrological analysis with the Rational Method, and hydraulic analysis using HEC-RAS 6.3.1 Software. The results of the analysis show a comparison of the total flood discharge with the channel discharge where 6 (six) drainage points are unable to accommodate the total channel discharge, namely S3, S6, S7, S9, S10, and S14 on a runoff height of <5cm. Ujong Baroh Village obtained 5 (five) drainage channel points that were unable to accommodate the total channel discharge, namely S2, S4, S5, S11, and S12 with a runoff height of <5cm, while in Drien Rampak Village 3 drainage channel points have not been able to accommodate the total channel discharge, namely S6, S7, and S10 with a runoff height of 5-10 cm. Regarding several alternative recommendations that can be doable, namely normalization in the form of cleaning from sedimentation and garbage and the need to increase the channel dimensions and efforts need to be made to study and implement environmentally friendly drainage concepts such as integrating rainwater harvesting with infiltration wells or bio pore holes.