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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.

Natural fiber based composite materials are increasingly being developed as an environmentally friendly alternative to synthetic fiber-based composites. This study aims to characterize the thermal and mechanical properties of natural fiber composite materials and evaluate their potential use as sustainable materials. Composites are made using natural fibers as reinforcement and a polymer matrix through a specific molding method. Mechanical property characterization includes tensile tests, flexural tests, and impact tests, while thermal property characterization is carried out using thermal analysis to determine the thermal stability of the material. The test results show that the addition of natural fibers has a significant effect on improving the mechanical properties of the composite, especially tensile strength and elastic modulus, compared to the unreinforced matrix. In addition, natural fiber composites show quite good thermal stability over a certain temperature range, making them suitable for non-structural applications. Based on these results, natural fiber composite materials have the potential to be developed as environmentally friendly materials that have competitive mechanical and thermal performance.

The unknown exact flexural strength of low carbon steel, Randu ribs wood, paving stones, and lightweight bricks is a problem faced. The purpose of this research is to obtain the flexural strength of low carbon steel, Randu ribs, paving stones, and lightweight bricks. The research method is carried out through the preparation of low carbon steel specimens 16mmx200mm, Randu ribs 40mmx60mmx250mm, paving stones 55mmx100mmx200mm, lightweight bricks 95mmx100mmx300mm, Tarno Grocky flexural testing machine settings, flexural testing support distance for low carbon steel 160mm, Randu ribs 220mm, paving stones 170mm, and lightweight bricks 260mm, flexural testing of each material, making flexural stress and deflection curves for low carbon steel, and analyzing flexural test results. The results of the study showed that the flexural strength of low carbon steel was 698 MPa at a deflection of 1.1 mm, the flexural strength of Randu rib wood in an upright position was 40.7 MPa, in a horizontal position was 55.5 MPa, in a normal position of paving stone in an upper position (normal) was 6.64 MPa, in a lower position (upside down) was 6.62 MPa, and in a lightweight brick was 1.28 MPa, which implies that the type of material, the distance between supports and the cross-section of the specimen greatly affect its flexural strength, except for ductile materials for low carbon steel which do not have flexural strength, but have yield strength at a certain deflection.

Leaf springs serve as vehicle weight supports and vibration dampers from uneven roads. Reducing vehicle weight can support fuel consumption reduction. The use of composite materials allows for a reduction in leaf spring weight without reducing load capacity and stiffness. The purpose of this study was to find the composition of composite leaf springs with a polyurethane matrix that were resistant to tensile and flexural tests using e-glass, epoxy, and polyurethane materials. This study used an experimental method, in which specimens were tested using a tensile and flexural testing machine. The variations included polyurethane matrices of 10%, 20%, and 30%. The data was statistically analyzed using Excel to determine the significant effect of the variables. The results showed the effect of polyurethane variation on the composite. The tensile test showed that the greatest tensile stress was on the 30% polyurethane specimen at 1.574 N/mm² and the smallest was on the 10% specimen at 7.007 N/mm². In the flexural test, the greatest effect on flexural strength was observed in the 30% specimen at 14.36 MPa and the smallest in the 10% specimen at 25.82 MPa. Without the addition of polyurethane, the tensile stress was 39.678 N/mm² and the flexural strength was 157.09 MPa. Conclusion: The addition of polyurethane reduces the mechanical strength of composite leaf spring material without polyurethane addition.

Leaf springs serve as vehicle weight supports and vibration dampers from uneven roads. Reducing vehicle weight can support fuel consumption reduction. The use of composite materials allows for a reduction in leaf spring weight without reducing load capacity and stiffness. The purpose of this study was to find the composition of composite leaf springs with a polyurethane matrix that were resistant to tensile and flexural tests using e-glass, epoxy, and polyurethane materials. This study used an experimental method, in which specimens were tested using a tensile and flexural testing machine. The variations included polyurethane matrices of 10%, 20%, and 30%. The data was statistically analyzed using Excel to determine the significant effect of the variables. The results showed the effect of polyurethane variation on the composite. The tensile test showed that the greatest tensile stress was on the 30% polyurethane specimen at 1.574 N/mm² and the smallest was on the 10% specimen at 7.007 N/mm². In the flexural test, the greatest effect on flexural strength was observed in the 30% specimen at 14.36 MPa and the smallest in the 10% specimen at 25.82 MPa. Without the addition of polyurethane, the tensile stress was 39.678 N/mm² and the flexural strength was 157.09 MPa. Conclusion: The addition of polyurethane reduces the mechanical strength of composite leaf spring material without polyurethane addition.

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.

This paper was made to explain the results of research on how to obtain the most appropriate citric acid adhesive composition in the manufacture of randu wood fiber composites in order to obtain a strong and suitable composite material. The research was carried out by experimental methods in the laboratory through a series of mechanical tests, namely the bending strength test and the screw grip strength test. The sample specimen is 5 cm × 20 cm × 1 cm for flexural strength testing and 5 cm × 10 cm × 1 cm for screw grip strength test. Composite specimens were made with variations in the composition of citric acid adhesives of 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5%, and 20% by weight of randu wood. The results showed that the composite of randu wood particles with a citric acid matrix had optimal strength at a certain ratio, which was 7.5%. At the same ratio, the test results of the screw grip strength test also provide the highest value. These findings confirm that the exact composition of the adhesive has a significant impact on the final performance of the resulting composite.

Concrete roof tiles are an important material in building construction, particularly for roofing work, due to their advantages in terms of strength, durability, and material availability. This study aims to analyze two main physical characteristics of concrete roof tiles, namely bending load and water absorption, using a literature review approach from various previous studies. Bending load refers to the material's ability to withstand bending forces, while water absorption describes the material's capacity to absorb and store water through its pores. These two properties significantly influence the quality and durability of roof tiles in facing external environmental conditions, especially wet-dry cycles and mechanical loads. The results of the literature review indicate that the use of waste as an aggregate substitute in concrete mixes can significantly improve the performance of concrete roof tiles. For example, research using broken roof tiles and ceramic waste as aggregate substitutes successfully increased flexural strength to a range of 12.5–15.0 MPa. Meanwhile, variations in water absorption were recorded in the range of 4%–8%, depending on the material composition and production method. This proves that the use of recycled materials not only supports sustainability but also improves the mechanical and physical properties of concrete roof tiles. Overall, this study underscores the importance of material innovation in concrete roof tile production, particularly utilizing waste as an alternative aggregate. However, further research is needed to explore the best combination of materials and production techniques for producing high-quality, efficient, and environmentally friendly concrete roof tiles.

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

This study examines the performance of a total of ten reinforced concrete T-beams, nine of which were made as hybrid beams by casting the web with LW concrete and the flange with HS concrete; the last beam was cast as a normal beam (entirely cast with HS concrete). All beams underwent testing under two-point loads following a 28-day period. The variables of the experimental program include the concrete grade within the web (46, 62, and 82 MPa) and stirrup distribution distances (100, 200, and 300 mm). The experimental program includes load-deflection curves and failure modes for hybrid and normal beams. The results showed that all the beams failed in shear-flexural mode. Also, increasing flange compressive strength increased shear. strength. Increasing stirrup distribution distance from 100 to 200 and 300 mm reduced the ultimate load capacity; specimens with stirrup spacing of 300 mm failed directly after yielding of steel due to crushing the concrete over the support and spalling concrete cover within the shear zone. The study also determined that reducing stirrup spacing to 100 mm did not alter the failure mode, as shear failure was dictated by the compressive strength of the lower layer of the hybrid beams (19 MPa compressive strength of LW concrete).

Concrete is an important aspect of building construction, one of which is road construction. Concrete is used for road construction because it has the advantages of high compressive strength, easy maintenance, ease of formation, and easy to obtain components. Road construction using concrete is applied to the reconstruction of the Kebumen South Ring Road, where the Kebumen South Ring Road is a 9.07 km long national road. National roads are arterial and collector roads in the primary road network system that connect provincial capitals, national strategic roads, and toll roads. Therefore, construction on national roads requires strong and good materials on the Kebumen South Ring Road to optimize road use. In this study, the concrete is composed of Bima cement as Portland cement, coarse aggregate from Kebumen, fine aggregate from the Progo River, and water from drilled wells. The admixture was obtained from a Conmix HK 2. Subsequently, all ingredients were mixed using a mixer truck. The concrete mixture was molded into cylinders and blocks. In this study, the average results of the 5-day concrete compressive strength test were obtainedwhich is 373.42 kg/cm2 and 28-day-old concrete is 442.32 kg/cm2. The average result of the 5-day concrete flexural test is50.65 kg/cm2 and that of 28-day-old concrete was 60.73 kg/cm2. The results are in accordance with the general specifications of the Bina Marga, namely, 45 kg.

Leaf springs are one of the suspension systems that are still widely used in various modes of transport such as cars and trucks. The spring functions to support the load and reduce vibration from operational activities. This study aims to analyse the bending strength and hardness of steel leaf springs of trucks and cars resulting from tempering heat treatment. The three point bending method was used as the flexural strength testing method and the Rockwell C Hardness method testing was used for hardness testing with leaf springs in raw, tempered 460°C, and tempered 510°C conditions. From the results of the study, the highest average bending strength value of 3733,55 MPa was obtained and an average roughness value of 31,8 HR was obtained for the 510°C tempered truck leaf springs. This also applies to the 510°C tempered car leaf springs, where the average bending strength value obtained is 3392,65 MPa and the average hardness value obtained is 29,5 HR. Thus, it is recommended that tempering heat treatment that can be applied to truck and car leaf springs be carried out at 510°C to increase the bending strength and ductility of the leaf springs.

A mixed-use building refers to a combination of several different functions within a single structure, such as residential, office, shopping, and recreational functions built on one site. Designing a mixed-use building requires careful planning and consideration of various factors such as functional needs, aesthetics, and energy conservation. Additionally, the design of mixed-use buildings incorporates various functions within a single area. Floor slabs and beams use plain reinforcing steel with a quality of Fy = 240 MPa (Ø8mm). The concrete cover is taken as 20 mm. From the design results, several thickness types of slabs were obtained according to the load requirements that must be accommodated above them. The following are the moments acting on the floor slabs and beams. The reinforcement calculations are performed using the capacity strength design method according to SNI 2847-2019. The capacity design concept involves controlling the formation of plastic hinges at predetermined locations. The SAP2000 program can directly calculate the feasibility of the structural dimensions and the amount of reinforcement needed from the input program results. In the SAP2000 program, the concrete code used is the American concrete code ACI-318-05/IBC 2003, which differs in some respects from the concrete code in Indonesia SNI 2847-2019. Adjustments need to be made to comply with the regulations in Indonesia. Internal forces from the SAP2000 program are selected from load combinations that generate the maximum moments at the column face. The flexural and shear reinforcement for beams can be directly read from the SAP2000 output in the form of information on the required area of reinforcement. 

A mixed-use building refers to the combination of several different functions in one building, such as residential, office, shopping, and recreational functions built on one site. Designing the structure of a mixed-use building requires careful planning and consideration of various factors such as functional needs, aesthetics, and energy conservation. Additionally, the design of mixed-use buildings includes various functions in one area. The floor slabs and roofs use plain reinforcing steel with a strength of Fy = 240 MPa (Ø8mm). Concrete cover is taken as 20 mm. The design results in several types of slab thicknesses according to the working loads that must be accommodated above them. Below are the moments acting on the floor slabs and roofs. Reinforcement calculations are carried out using the capacity strength design method according to SNI 2847-2019. The concept of capacity design refers to controlling the formation of plastic hinges at predetermined locations. The SAP2000 program can directly calculate the feasibility of structural dimensions and the required reinforcement area from the input program results. In the SAP2000 program, the concrete regulations used are those of the American Concrete Institute ACI-318-05/IBC 2003, which in some aspects differ from Indonesian concrete regulations SNI 2847-20219. Adjustments need to be made to comply with Indonesian regulations. Internal forces from the SAP2000 program are selected from load combinations that produce the maximum field moments and support moments at the column faces. Flexural and shear reinforcement of beams can be directly read from the SAP2000 program output in the form of the required reinforcement area information

Background: Glass Reinforced Concrete (GRC) is an innovative construction material that combines glass fiber with concrete, providing high strength and durability. However, the influence of GRC mixture composition on flexural strength values has not been studied in depth. Therefore, this study aims to analyze the effect of GRC mixture composition variables, such as the ratio between glass fiber and concrete binder, on flexural strength. It is hoped that the results of this research can provide deeper insight into the use of GRC in construction and help develop more efficient and durable construction materials. Results: From the results of the discussion regarding the effect of differences in fiberglass composition on flexural strength, it was found that the addition of 2% fiber resulted in an average flexural strength of 23.01 kgf/cm2, with an increase of up to 49.77 kgf/cm2 at 1% fiberglass. However, with a fiber composition of 0.8%, the highest flexural strength was obtained at 56.84 kgf/cm2. The addition of fibers that exceed the maximum limit can reduce the density of GRC concrete so that its ability to distribute bending strength forces is reduced. Meanwhile, the effect of fly ash substitution on flexural strength shows that replacing some of the cement with fly ash by 20% can increase the flexural strength value of GRC, because the silica and alumina compounds in fly ash can speed up the hydration process. However, of the five specimens tested, none met the SNI 8299:2017 standard which requires a minimum average flexural strength of 100 kgf/cm2

The development of science, especially in the field of transportation, especially roads, requires adequate infrastructure in the form of roads or pavement that is suitable for the conditions in the field. This research aims to determine the analysis of the addition of strapping band fibers on the flexural strength of concrete, the variation in influence is 0.5%, 1 .0%, 1.5%, the best composition for making rigid pavement flexural strength. This research uses experimental research methods, namely research in the laboratory which aims to investigate the effects of each other and compare the results. The research results of 4 variations, namely 0% (normal), 0.5%, 1.0% and 1.5% of fine aggregate, in testing concrete aged 28 days on normal concrete were 3.333 Mpa, for variations of 0.5% on average an average of 2,800 Mpa, a 1.0% variation an average of 2,133 MPa, and a 1.5% variation an average of 1,333 MPa. So it can be concluded that concrete with a variation of 0.5% achieves the design strength and is suitable for use. Meanwhile, variations of 1.0%, 1.5% do not reach the design compressive strength and are not suitable for use in construction.

Self Compacting Concrete (SCC) is an innovative concrete that can compact itself (without vibrators) and flow under its own weight to saturate the shape without segregation. The SCC material is not much different from ordinary concrete, namely coarse aggregate, fine aggregate, cement, water, only SCC has additional ingredients such as superplasticizer. This research uses quantitative methods. The aim of this research is to determine the workability, compressive strength, flexural strength of SCC concrete with the addition of 2% fiberglass to each sample with added material in the form of sika visconcrete with variations of 0%, 1%, 1.5%, and 2%, % of the cement weight. Slump flow testing was carried out which was obtained from several variations of SV `0%, 1%, 1.5%, 2%, the slump flow values were obtained for 80 mm fiber concrete and 550 mm, 575 mm, 600 mm SCC concrete with the time taken to reach 500 mm of 4.25 seconds, 3.57 seconds and 2.11 for SCC concrete. The compressive strength value of the cylinder size (15 x 30) in samples BFS0, BFS1, BFS2BFS3 aged 28 days obtained a compressive strength of 30.29 Mpa, 34.44 Mpa, 31.23 Mpa, while the flexural strength test of the beam was 15 x 15 x 60 d samples BFS0, BFS1, BFS2BFS3 obtained results of 3.11 Mpa, 4.35 Mpa, 3.64 Mpa and 3.29 Mpa, excessive use of visconcrete in the concrete mixture can reduce the strength of the samples.

Innovations in concrete design continue to be made to obtain maximum strength. The granulated sugar can be an added ingredient that functions to inhibit the concrete setting time so it doesn't dry out too quickly. Use to delay concrete setting time (setting time) for example with hot weather conditions, or extend compaction time to avoid cold joints and avoid the impact of settlement when fresh concrete is carried out at the time of casting. As for the curing experiment/treatment of the concrete by immersion in seawater to find out how construction buildings on the seaside affect construction such as bridge abutments, pile caps or buildings on the coast that are submerged or exposed to sea water whether there is a decrease in the quality of making concrete blocks. The experiment was carried out by adding a variety of granulated sugar to the concrete mixture of 50 grams (2% by weight of water), 70 grams (3% by weight of water) and 100 grams (4% by weight of water) then all the samples were immersed in sea water. Based on the results of the flexural strength test of concrete after 28 days of age, the highest test results obtained for the flexural strength of concrete were the addition of 100 grams of granulated sugar worth 3.00 MPa for the second was the addition of 50 grams of granulated sugar worth 0.515 MPa and for the third was the addition of sugar sand 70 grams 0.454 Mpa. This composition cannot be said to have decreased due to immersion in sea water, because there is no proven comparison with immersion using ordinary water.

Self-compacting concrete (SCC) is self-flowing concrete that can be printed on formwork with very little or no compaction. One of them is by adding admixture superplasticizer. The purpose of this research is to determine the effect of superplasticizer admixture with various variations on flexural strength. The method used in this research is the experiment of adding superplasticizer admixture to the concrete mixture with variations of 3%, 4% and 5%. The sample was made of 3 test objects in the form of blocks with dimensions of 15 cm x 20 cm x 100 cm for a design value of 15 MPa. Based on the results of the flexural strength test of concrete beams after 28 days of flexural strength testing, the highest yield was obtained in the second sample of 4% mixture with a maximum P load of 32.2 KN after converting to 18.22 MPa. Whereas for the 1st sample it was a 3% mixture with a maximum P load of 22 KN after converting to 12.44 MPa and for the 3rd sample it was a 5% mixture with a maximum P load of 22.9 KN after converting it to 12.95 MPa. 3. It was found that the average of the 3 samples was 14.54 MPa, a little more to exceed the target of 15 MPa.