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The problem of urban flooding is a growing issue due to high population density, increasing volumes of plastic waste, and the reduction of water absorption areas. The use of conventional paving blocks, which are impermeable, further exacerbates flooding conditions because they do not allow water to infiltrate into the soil. This study aims to develop an innovative plastic waste-based paving block incorporating rice straw and sugarcane bagasse, along with the integration of phytoremediation concepts as a solution for urban flood mitigation. The method employed was an experimental approach involving the following stages: material preparation, plastic incineration, material mixing, molding, and testing of water absorption capacity and compressive strength. The results showed that paving blocks with a combination of plastic waste, rice straw, and sugarcane bagasse had the highest water absorption rate of 34% and compressive strength of 21 kg/cm², meeting SNI standards. The addition of natural materials containing silica was proven to enhance the material’s porosity and strength. Additionally, the application of phytoremediation using water hyacinth has the potential to improve the quality of water seeping into the soil. Thus, this phytoremediation-based paving block innovation can serve as an effective alternative solution to reduce flood risks while supporting sustainable waste management and environmental stewardship.

Self-Compacting Concrete (SCC) requires a high cement content, which contributes to increased carbon emissions; therefore, this study evaluates the effect of partial cement substitution with fly ash (5%, 10%, and 15%) and the addition of Polyethylene Terephthalate (PET) waste (0.5% and 0.7%) on the mechanical properties of SCC with a target strength of f’c 30 MPa. The research employed laboratory experimental methods, including fresh concrete tests (slump flow, L-box, and V-funnel) and hardened concrete tests (compressive, tensile, and flexural strength) at 7 and 28 days. The results indicate that fly ash substitution enhances compressive strength, with the highest value of 49.59 MPa achieved at 5% fly ash at 28 days, exceeding normal concrete (34.73 MPa). The addition of PET tends to reduce compressive strength due to increased porosity; however, it significantly improves flexural strength, as the combination of 5% fly ash and 0.5% PET achieved 4.7 MPa compared to 2.9 MPa for normal concrete. Overall, the combination of fly ash and PET waste shows potential for application in structural elements requiring high flexural performance.

Slope stability studies are crucial in determining the sustainability and operational safety of mining activities. This research was conducted to analyze the correlation between rock porosity and Unconfined Compressive Strength (UCS) results, as well as the corrleations between Point Load Index (PLI) and Unconfoned Compressive Strength (UCS) results. These two correlations form the primary components of the study. Three types of rock were tested claystone, coal, and siltstone. The results of the study are as follows for the correlation between porosity and Unconfoned Compressive Strength (UCS), claystone yielded a coefficient of determination (R2) of 0.32 is classified as weak correlation, with the linear regression equation Y=-0.11X+6.98. Coal yielded an (R2) of 0.56 is classified a moderate correlation, with the equation Y=-1.98X+103.77. Siltstone yielded an (R2) of 0.86 is classified a strong correlation, with the equation Y=-0.38X+20.02. Regarding the correlation between Point Load Index (PLI) and Unconfoned Compressive Strength (UCS), claystone achieved an (R2) of 0.12 is classified a very weak correlation, with the linear regression equation Y=8.91X. Coal achieved an (R2) of -0.27 is classified a very weak correlation, with the equation Y=27.87X. Lastly, siltstone achieved an (R2) of -0.45 is classified a very weak correlation, with the linear regression equation Y=24,90X.

The increasing demand for housing in tropical regions requires building materials that are fast to apply, environmentally friendly, and resilient to extreme climate conditions as well as disaster risks. Conventional interlocking bricks are often chosen for their ease of construction, yet they still face challenges such as moisture and early cracking. This study proposes the innovation of the Hybrid Living Green Brick, a combination of lightweight bricks made from rice husk ash and fly ash waste (FRCB) with a biological layer of cyanobacteria. FRCB improves compressive strength by approximately 30% with the addition of 5% rice husk ash, achieving 65 kg/cm², thereby meeting Class 50 requirements (≥50 kg/cm²) according to SNI-15-2094-2000. The incorporation of 3% cyanobacteria provides an additional though not significant strength improvement, while still within the Class 50 category. It also reduces brick weight by 4.3%, with further optimization potential through cyanobacteria integration, and lowers carbon emissions from the firing process. Cyanobacteria induce the formation of CaCO₃ layers that seal pores, reduce water absorption by an average of 10%, and provide self-healing properties for microcracks. Preliminary observations indicate that FRCB offers stable mechanical performance, while biological activity was observed on the 7th day with the formation of pale-white mineral layers continuing until the 28th day. This hybrid innovation shows potential to support sustainable and disaster-resilient tropical construction by combining the mechanical strength of waste-based materials with the biological durability of cyanobacteria against extreme climates. Despite challenges related to moisture control and production standardization, the Hybrid Living Green Brick concept opens new pathways for developing environmentally friendly construction materials that are more adaptive to disaster-prone tropical conditions.

The use of laminated bamboo columns as alternative building materials has attracted increasing attention, particularly as a substitute for wood in construction. Bamboo lamination techniques enable the production of structural materials with tailored mechanical properties. Numerous previous studies have investigated the compressive strength of laminated bamboo short columns subjected to various treatments. This study aims to evaluate the compressive strength and failure patterns of laminated bamboo short columns under compression loading. The experimental program included physical and mechanical characterization of bamboo, followed by compression testing of laminated bamboo short columns with dimensions of 10 cm × 10 cm × 30 cm. Three treatment variations were examined: untreated laminated columns, epoxy resin–coated columns, and steel plate–reinforced columns. The results indicate that untreated laminated bamboo columns exhibited an average compressive strength of 28.044 MPa, with cracking concentrated at the top of the column. Epoxy resin–coated laminated bamboo columns achieved an average compressive strength of 28.774 MPa, showing crack formation distributed across several regions of the column. Steel plate–reinforced columns demonstrated the highest average compressive strength of 31.138 MPa, with failure localized in the region between the steel plates. These findings provide valuable insights into the effectiveness of different treatment methods in enhancing the compressive performance and failure characteristics of laminated bamboo columns.

The development of science and technology generally brings positive impacts in terms of convenience in various human activities, but on the other hand, it also leads to negative consequences such as an increase in waste. One of the significant wastes produced from construction activities, including building and house construction, is feldspar, which typically comes from leftover ceramic materials. Feldspar is a type of waste that is difficult to decompose naturally and has no economic value, often accumulating and polluting the environment. Therefore, innovation is needed to utilize this waste to create value. This study aims to use feldspar powder as a replacement for fine aggregates in K-200 grade concrete mixtures. The research method involved mixing feldspar powder in specific proportions as a substitute for sand, followed by a series of tests, including compressive strength and flexural tests, to determine the feasibility and performance of the resulting concrete. The results indicate that the use of feldspar powder as a fine aggregate produces a concrete mixture with satisfactory mechanical characteristics, meeting the K-200 concrete standards. These findings not only provide an alternative environmentally friendly material but also offer a solution to reduce ceramic waste, contributing positively to sustainable construction.

A research about study of sandstone slope stability using the Bishop Simplified method in Uu Samarinda has been conducted. This study was conducted to analyze the rebound number values of sandstone slopes, evaluate their stability level, and calculate the safety factor using the Bishop method. The results showed that the rebound number values were 22.34 at point 1, 19.83 at point 2, and 18.07 at point 3. The Uniaxial Compressive Strength (UCS) values at the observation points were 1.90 MPa, 1.62 MPa, and 2.21 MPa, respectively. Geological Strength Index (GSI) evaluation indicated a rating of 80–85, demonstrating intact/massive rock structure, fresh and unweathered rock surfaces, and very good rock quality. Based on the Bishop method analysis, the slope factor of safety in 6.525  with a probability of failure is 0.000%, indicating that the sandstone slope in Ulu Samarinda is highly stable even under external pressures such as heavy rainfall or minor earthquakes. This study provides crucial information on the mechanical characteristics and stability of sandstone slopes in ulu Samarinda, which can serve as a reference for technical planning, geotechnical risk mitigation, and the sustainable development of safe areas.

Expansive clay soil is soil that can expand and contract significantly in response to changes in soil moisture content. This study used an experimental method to stabilize expansive clay soil using a mixture of gypsum waste powder, which was tested using the Atterberg test, the Unconfined Compression Strength test, and the California Bearing Ratio test with mixture variations of 0%, 10%, 20%, and 30%. The results showed that the addition of gypsum waste powder could reduce the expansivity level of the soil from a very high level of 42% to a moderate level of 20%, increase the value in the Unconfined test at a maximum mixture of 10%, and increase the value in the CBR test at a maximum mixture of 30%. Based on the above description, this study aims to determine the extent of the effect of gypsum waste powder on expansive clay soil on the bearing capacity and compressive strength of expansive clay soil.  

The use of sengon albasia ash waste as a partial cement substitute in concrete production is carried out to reduce combustion waste and also reduce cement use. This study focuses on the use of sengon albasia wood ash waste. The use of sengon albasia wood ash as a cement substitute causes a significant decrease in the slump test value. The use of sengon albasia wood ash as a partial cement substitute in concrete mixes actually produces different results depending on the proportion. If added as much as 10%, the concrete's compressive strength actually increases, but if it reaches 20% or 30%, the compressive strength actually decreases. This occurs because this type of wood ash has a significant water absorption capacity. As a result, the water that should be used for The chemical activity occurring between cement and water is diminished, so that the bond between the cement mixture as a binder and aggregate as a filler is reduced, and ultimately the concrete's compressive strength also decreases.

The soil in Kedungdandang Hamlet, Muncar, has previously been identified as expansive clay that is highly sensitive to changes in moisture content and exhibits significant shrink–swell behavior, which leads to a reduction in bearing capacity and structural damage such as cracking in floors and walls, therefore, soil improvement through stabilization is required. This study aims to determine the effect of adding cement and rice husk ash (RHA) on the mechanical properties of expansive clay soil by using 3% cement and 6%, 8%, and 10% rice husk ash based on the weight of the soil. The results of the unconfined compressive strength (UCT) test indicate that the natural soil has a qu value of 28.62 kN/m², which increases to 55.08 kN/m² with the addition of 3% cement and 6% RHA, to 62.66 kN/m² with 3% cement and 8% RHA, and reaches the highest value of 86.98 kN/m² for the mixture containing 3% cement and 10% RHA. This increase in qu value indicates that the stabilization process improves the mechanical properties of the soil through a pozzolanic reaction, resulting in a more stable soil structure and a higher bearing capacity.

Rock stability and service life in geotechnical and mining engineering are highly dependent on the rock's mechanical and physical parameters, where the variation in sandstone grain size is a crucial intrinsic factor. This study aims to comprehensively analyze the correlation between sandstone grain size with uniaxial compressive strength (UCS) and resistance to weathering (Slake Durability Index) in samples taken from the Balikpapan and Pulau Balang Formations in the Samarinda area, East Kalimantan. The research methodology involved a series of standard laboratory tests, including rock physical properties analysis, grain size distribution analysis, UCS testing, and slake durability testing through three cycles. The test results show a significant correlation: sandstone with finer grain sizes and higher density consistently demonstrates greater UCS values and a higher Durability Index, indicating superior mechanical and physical resistance. Specifically, the Pulau Balang Formation exhibits a more compact structure and finer grain size, resulting in better durability values compared to the Balikpapan Formation. These findings are important as a geomechanical data basis for slope design planning, rock mass stability analysis, and material selection in infrastructure projects or mining operations involving both formations.

Consistent and efficient concrete quality in each implementation is one of the main factors in the success of construction projects. Concrete as a structural material requires strict quality control in order to meet the technical standards that have been set. One way to improve the quality of concrete is to add certain additives to the job mix formula (JMF). This research is focused on the application of SG type additives known as chemical-based additives to improve the properties of fresh concrete and hard concrete. SG additives have an important function in increasing workability, speeding up or slowing down the binding time as needed, maintaining quality stability, and strengthening concrete finishes. In this study, a comparison was made between a concrete mixture with SG additives and a concrete mixture without additives. The tests included slump parameters, initial binding time, and compressive strength at 7 and 28 days of age. The test results showed a significant difference, especially in the improvement of the consistency and compressive strength of concrete with the use of additives. The results of the discussion showed a comparison of Trial Mix 1 and Trial Mix 2 that are different in terms of material composition, cost efficiency, and compressive strength of concrete. Trial Mix 2 with the composition of cement, admixture, water, and aggregate (sand and split) showed more optimal results. The compressive strength achieved was 821,396.00 kg/cm² at the age of 28 days. In terms of cost, Trial Mix 2 requires Rp. 351,582.00 per m³, with an efficiency difference of around Rp. 32,953.00 per m³ compared to the previous mix

This study analyzes the potential use of cockle shell waste and coal fly ash as alternative raw materials in the production of composite brake pads. The high volume of industrial and fisheries waste, which has not been optimally utilized, encourages the exploration of environmentally friendly materials with adequate mechanical performance. The main focus of this research is the compressive strength of the produced brake pads, as this parameter is crucial for ensuring effective and safe braking performance. The method used includes the mixing and molding of composite materials with varying compositions of cockle shell and fly ash, followed by compressive strength testing according to standards. This study also takes into account the environmental impact of using waste as filler material, which is expected to reduce reliance on conventional materials and decrease waste that contaminates the environment. The results of the study are expected to provide empirical data on the potential of these two wastes as fillers in brake pad matrices and to identify the optimal formulation that provides the highest compressive strength. This study contributes to the development of sustainable braking materials and efforts to mitigate the environmental impact of waste, while also opening opportunities for the reuse of waste that has previously been poorly managed.

This study investigates the potential of Low-Density Polyethylene (LDPE) plastic waste as a partial substitute for sand in concrete block mixtures, focusing on its effects on compressive strength and water absorption. LDPE is a non-biodegradable plastic waste that poses significant environmental challenges. Its incorporation into construction materials offers a promising solution to reduce pollution while enhancing the performance of building components. The research employed LDPE substitution levels of 10%, 15%, 20%, 25%, and 30% by weight of sand, compared against conventional concrete blocks without LDPE. Experimental results revealed that the highest compressive strength was achieved with a 15% LDPE mixture, reaching 80.762 kg/cm² at 28 days of curing—an increase of approximately 40.8% compared to normal blocks, which recorded 57.359 kg/cm². LDPE additions up to 20% maintained favorable strength characteristics, while higher proportions (25% and 30%) led to a decline in mechanical performance. In terms of water absorption, the inclusion of LDPE demonstrated a decreasing trend, attributed to the hydrophobic nature of plastic, which enhances moisture resistance in the concrete blocks. These findings suggest that a 15% LDPE substitution represents an optimal formulation for producing eco-friendly concrete blocks with improved strength and reduced water absorption. The study highlights the dual benefits of waste management and material innovation, aligning with sustainable development goals. By repurposing plastic waste into construction applications, this approach not only mitigates environmental impact but also contributes to the advancement of green building technologies. Further research is recommended to explore long-term durability, thermal properties, and scalability of LDPE-based concrete products in real-world construction settings.

This study aims to analyze how internal strategies and external challenges can influence the achievement of Regional Original Revenue targets at the Laboratory Technical Implementation Unit (UPTD) of the Public Works and Public Housing Agency (Dinas Pekerjaan Umum dan Perumahan Rakyat) of Cilacap Regency. The research object is the performance of the Laboratory Technical Implementation Unit (UPTD), a technical unit providing construction material testing services, which directly contributes to Regional Original Revenue in Cilacap Regency. The qualitative approach employed a case study method, and data collection techniques included interviews, observation, and documentation. The sample in this study was obtained purposively. The results indicate that internal strategies focused on superior testing methods such as core drilling, abrasion, and concrete compressive strength have been conducted. However, limited equipment, human resources, and the lack of accreditation are major obstacles. On the other hand, external challenges include the lack of updated Regional Regulation tariff regulations, the absence of formal obligations for the use of laboratory services for regional budget projects, and a saturated local market. These findings provide important implications for the Laboratory Technical Implementation Unit (UPTD) in emphasizing policy revisions, increasing internal capacity, and strengthening inter-agency coordination to increase Regional Original Revenue realization.

The durability of Self-Compacting Concrete (SCC) containing fly ash and Sika Viscocrete can be affected by exposure to seawater. This research investigates how seawater curing impacts the compressive strength of SCC modified with varying fly ash content and Sika Viscocrete admixture. The concrete mixtures were designed with 0% and 30% fly ash by cement weight and a constant 1% dosage of Sika Viscocrete. Compressive strength tests were conducted at 7, 14, and 28 days. The findings indicate that seawater curing has a notable effect on compressive strength, producing generally higher strength values than those cured in freshwater. Under freshwater conditions, strength increased steadily at 14 and 28 days, peaking at 54.1 MPa with 30% fly ash at 28 days. Conversely, the highest strength under seawater curing was achieved earlier, at 7 days, also with 30% fly ash, reaching 56.1 MPa. Overall, the optimum compressive strength was attained with a 30% fly ash mixture cured in seawater, suggesting this method enhances early-age strength in SCC.

Compressive strength is one of the mechanical properties of rock behavior. This study focuses on the Balikpapan and Kampungbaru Formations located in the Kutai Kartanegara area, East Kalimantan. The Schmidt Hammer testing method was applied due to the lack of previous studies utilizing this tool to evaluate rock hardness in correlation with compressive strength. The research site is situated in the Kutai Kartanegara area, specifically in the districts of Muara Badak, Muara Jawa, and Sanga-Sanga. Field observations revealed the presence of claystone slopes at predetermined locations. Based on the test results, the uniaxial compressive strength (UCS) values for the Balikpapan Formation range from 3.453 MPa to 5.454 MPa, while the Kampungbaru Formation ranges from 3.317 MPa to 8.571 MPa. The Schmidt Hammer rebound number (RN) values for the Balikpapan Formation range from 17 to 19.6, and for the Kampungbaru Formation from 15 to 23.7. A negative correlation was found between the rebound number and UCS, where higher RN values tend to correspond with lower UCS values. This is supported by the linear regression analysis showing a negative coefficient (-0.450).  

This research was conducted to analyze the performance of the extruder machine on the production quantity and quality of bricks. Analysis shows that the engine transmission uses a type B belt with a belt circumference of 1063.622 mm, so the v belt used by the motorbike has a nominal belt number of 41 inches. From the results of the linear regression of red bricks before being burned with a correlation value of 98.7%, it can be categorized as very strong. The linear regression for red bricks before burning is 0.10 while alpha < 0.05 so it can be concluded that there is no significant influence on variables X and Y. The linear regression for red bricks after burning is 0.07 while alpha < 0.05 so It can be concluded that there is no significant influence on variables X and Y.

This research utilizes waste from PLTU Tanjung Jati B Jepara, namely FABA (Fly ash Bottom Ash) as an alternative to fine and coarse aggregate. From this research, the physical properties of faba aggregate can be seen from the results of the faba aggregate sieve analysis test, which obtained a fineness modulus value of 1.74, which is included in the medium aggregate type. The water content of fine aggregate (fly ash) obtained a value of 3.63% and coarse aggregate (bottom ash) obtained a value of 1.5%. The fine aggregate sludge content (fly ash) obtained a value of 0%. The fine aggregate organic substance (fly ash) acquires a reddish brown NaOH color, therefore it must be washed before being used as a concrete mixture. The face dry specific gravity of fine aggregate (fly ash) obtained a value of 2.63 gr/cm2 and coarse aggregate 2.52 gr/cm2. From the data that has been obtained, faba aggregate is considered to have physical properties that meet the requirements for fine aggregate and can be used as a substitute for sand. The results of the final compressive strength of faba concrete and normal concrete at the age of 7 days and 28 days showed that the compressive strength of normal concrete (control) was higher than that of faba concrete. The standard deviation values ​​at the ages of 7 and 28 days are included in perfect working conditions because they have a standard deviation value of less than 3 MPa. From the results of the concrete flexural strength test, only the control concrete was 1;1.5 with a flexural strength of 4.18 MPa, which is close to SNI 2847:2013, namely with a minimum flexural strength of fs = 4.4 MPa. Normal concrete has a higher flexural strength than faba concrete. Based on tests carried out with the planned mix design, the 1:1.5 variation obtained the highest results.

This research is an experimental study on porous concrete and the use of fly ash as a binder for concrete to analyze the effect of compressive strength and porosity. The research method used in this study is the experimental method which is a research method used to find the effect of certain treatments on concrete. In this research, the concrete mix design uses a ratio of gravel and geopolymer paste as a binder, namely 4: 1 and uses a molarity ratio of 10M with differences in grading of coarse aggregate using sieves number 4, 1/2 ", and 3/8". The optimum compressive strength value was obtained in mix design 1 using sieve gradation no.4 which was 4.25 MPa at 28 days old. While the results of the highest porosity value were found in mix design 1 which was 7.15% at 28 days old