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Construction cementitious materials or construction-based materials, such as cement paste, mortar, and concrete, are one of the most utilized materials in building construction today. This material's advantages include its high compressive strength, durability, lower labor costs, and applicability to a wide range of building applications. In its use, this material is susceptible to shrinkage, which produces a decrease in the material's volume because of reduced moisture content and loss of water during the hardening process. In a mixture of cement-based construction materials with a low water-cement ratio, superabsorbent polymer (SAP) is known to be one of the materials with "healing agent" capabilities. In addition, the usage of this material can automatically cover cracks. This study aims to examine the use of superabsorbent polymer in improving the durability of cement-based construction materials, as well as the problems that could occur if this material is applied in Indonesia. Several techniques, including data collection techniques, data reduction, data analysis, data presentation, and drawing conclusions, are used to conduct a literature review. The result of this research is a literature review on the definition of SAP, its durability, and its challenges in Indonesia. [ABSTRACT FROM AUTHOR]

Self-healing concrete (SHC) is a concrete material innovation which can cure a crack on the concrete by microorganism supplementary as a healing agent. Besides, plastic is a material frequently utilized, yet it increases the amount of plastic waste in environment. Thus, the plastic waste has been developed as a synthetic fiber inside the concrete. Plastic waste supplementary in SHC has potential in increasing mechanic characteristics on the concrete. However, research discussing plastic waste substitution in SHC has been uncovered. This research aimed at analyzing load strength value ability accession, elasticity modulus, strength of tensile, and evaluation result resulted from crack cover of SHC Bacillus subtilis bacteria based with the substitution of plastic waste on the concrete was normal. This study employed experimental method by utilizing two compositions of concrete: A's composition (bacteria concrete and plastic fiber) and R (normal concrete). Both of compositions later would be molded consisting of 3 cylinders 150×300 mm and 3 prism 75×75×150 mm. Next, the treatment was undertaken for 28 days before testing. To evaluate the crack, the tested concretes were placed into three different treatments; indoor, outside, and immersed on water. Furthermore, the research showed the elasticity modulus value, and it decreased up to 7.75%, compared with normal concrete. The crack closure evaluation showed that crack closure in concrete by immersed on water by coverage as calcium carbonate sediment in the crack area on the 14th and 28th compared with other treatment. [ABSTRACT FROM AUTHOR]

The reinforced concrete beam structure plays a role in receiving bending force and shear force so that it will undergo deformation during loading. In order to maximize the performance of the beams, reinforcement is added to help in withstanding tensile stresses because the concrete is weak against tensile. If the deflection arising from large loading results in the servisability of the beam is also less comfortable. For this reason, the rigidity of the beam needs to be designed so that the deflection of the beam can be limited. Realizing the importance of rigidity to the behavior of structures, the researchers conducted research on the behavior and characteristics of graded concrete beam. This research was conducted to determine the effect of singly and doubly reinforcement configurations on the rigidity of graded concrete beam. There were six specimens in this study. Each specimen is formed with two concrete mixtures, namely 20 MPa and 40 MPa with a beam shear span ratio of 2.5. Testing was performed numerically using the FEA application. The results showed that the behavior of single-reinforced and double-reinforced graded beams was between their control beams. Then, the double reinforced configuration on the gradation beam results in higher rigidity than the single reinforced gradation beam with an increase of up to 27.51%. The deformation ability of double reinforced gradation beams has increased by up to 38% than that of single-reinforced gradation concrete beams. In addition, with a double reinforcement configuration, the curvature of the gradation concrete beam is reduced to -2.19%. The design of the double reinforcement configuration is more recommended as a reinforcement for gradation concrete beams in subsequent studies. [ABSTRACT FROM AUTHOR]

The expected failure of the structure is an important parameter to consider when designing reinforced concrete beams. The magnitude of tensile and compressive stresses due to loading, which is determined by the reinforcement configuration, has a large influence on structural failures. The addition of reinforcing steel can improve the resistance of reinforced concrete beams to tensile stress, but it reduces the beam's ductility. On the other hand, in recent years, reinforced concrete innovation has been developed in an effort to optimize the performance of beams by grading the quality of concrete. In comparison to normal concrete beams, reinforced graded concrete beams (RGCB) exhibit more complex behavior. Based on this, this study was carried out to investigate the effect of single and double reinforcement on RGCB. In the modeling, RGCB with concrete quality of 40 MPa on compressed fibers and 20 MPa on tensile fibers was modeled. The beam geometry is b=179 mm, h=358 mm, and the a/d ratio is 2.5. All specimens of the test object are designed with a low rebar ratio in the expectation that the beam will be ductile. The study's findings are as follows: (1) the crack pattern created on the RGCG resembles a higher quality control concrete beam; (2) RGCB experience bending failure in the middle of the span followed by shear failure; (3) the use of different concrete strengths in RGCB creates an unsustainable cracking pattern; and (4) the use of double reinforcement on RGCG shows more distributed strain propagation compared to RGCG with single reinforcement. [ABSTRACT FROM AUTHOR]

Concrete is the largest contributor to carbon emissions in the construction sector. However, recently there have been no studies analyzing embodied carbon in normal concrete with specific reviews on one structural element and reinforced concrete buildings with variations in structural configuration. The purpose of this study is to determine the influence of material variables and designs of reinforced concrete beam and reinforced concrete buildings on the value of embodied carbon which can then be used as a consideration of low-emission building design. This research was conducted using parametric analysis methods using Building Information Modeling-based applications and ICE Cement, Mortar, and Concrete Model – V1.1 Beta. Reinforced concrete beam were designed with single reinforcement with minimum and maximum reinforcement ratio and in cross-sectional dimension ratios, namely 1:3, 1:2, and 2:3. Reinforced concrete buildings were designed with 3 variations of column elevation, namely 3000 mm, 3500 mm, 4000 mm, and 3 variations in beam span, namely 3000 mm, 4000 mm, 6000 mm. The results of this study show that the greater the ratio of width to height of the beam (b/h) and the reinforcement ratio, the higher the embodied carbon produced. The denser and higher the elevation of the column used, the greater the embodied carbon produced. In reinforced concrete buildings, the cradle-to-gate stage produces embodied carbon by 49.69%, the construction stage by 2.93% and End of Life by 4.39%. [ABSTRACT FROM AUTHOR]

Based on the empirical equation, the calculation of the bearing capacity of the pile foundation is influenced by the characteristics of the soil indicated by the cone resistance and friction (CPT) and the SPT value. However, determining the bearing capacity is also influenced by the material parameters of the foundation used. Based on SK SNI T-15-1991-03 [1] and ACI 363-92 [2], the determination of the concrete elasticity modulus is influenced by density, concrete compressive strength, and the correction factor. The value of this parameter can affect the bearing capacity and the settlement. Based on this, this study analyzes the behavior of driven single concrete piles at a diameter of 400 mm on the downward and uplift bearing capacity and the settlement with the variation of concrete compressive strength. This parameter can affect the elasticity modulus and the density of the material. The analysis was carried out using the Allpile program and empirical equation. The pile was reviewed at depth of 8 meters on clay soil. The results show that the downward bearing capacity is not affected by the weight, density, concrete compressive strength, and elasticity modulus (pile parameter material). Meanwhile, the result of the uplift bearing capacity is influenced by the alteration in the weight and density which affect the compressive strength and elasticity modulus. The value of the elasticity modulus affects the settlement of the foundation. The relationship that results in a corresponding point between weight, settlement, and uplift bearing capacity occurs approximately at 2.78 kN/m, 0.032 cm, and 94.6 kN. [ABSTRACT FROM AUTHOR]

Research-based on numerical studies requires comprehensive competence at least in determining material properties, failure criteria, element modelling, boundary conditions, and loading iterations used. The results of reliable modelling of materials, elements, and structures can be used as a validation instrument from the results of previous experimental tests or as a preliminary study before carrying out laboratory-based research. Reinforced concrete is a composite material that has complexity in numerical modelling. Errors in determining the interaction between the constituent materials and elements interaction result in a non-converging solution. Previous research related to numerical studies of graded concrete beams found that there were limitations so that the results of the analysis could not be compared with the experimental results. In this study, the research intends to evaluate the basics and approaches to modelling graded concrete beams, especially in terms of the constitutive model of the material used. The results of the study show that: (a) Kent and Park's constitutive concrete model can be used as the basis for developing a simplified damage plasticity model approach for finite element modelling of graded concrete; (b) Graded concrete beams can provide a level of performance in the form of elastic stiffness and load capacity in yield conditions; (c) Graded concrete beams have better post-rupture load resistance, which is characterized by a slower rate of increase in deflection and strain of tensile reinforcement, compression reinforcement, and tensile fibre concrete; and (d) Graded concrete beams can dissipate maximum energy through the crack formation along the beam span. [ABSTRACT FROM AUTHOR]

The application of lean construction principles aims to minimize waste, reduce variability, increase reliability and productivity, and increase efficiency. This is in line with the aims of the development of graded concrete (GC) on structural elements which is predicted to reduce the use of cement but still maintain the performance of the designed structures. Previous research only focused on the structural performance of GC beams without assessing the cost aspects that are considered in its implementation in the projects. This research aims to further analyse the costs and benefits of implementing GC in construction on varying reinforcement ratios. This research was conducted experimentally in the laboratory. Several GC beams were prepared and tested under the four-point bending method. The results showed that the GC beams with maximum reinforcement are not feasible applied in the project construction due to higher cost. It is recommended to design GC beams using the minimum reinforcement ratio because it provides a greater increase in load-carrying capacity but at a more affordable cost. [ABSTRACT FROM AUTHOR]

The combination of concrete and steel in reinforced concrete beam structures creates new composite material, reinforced concrete, with distinct properties. When compared to standard concrete beams, the incorporation of graded concrete in structures is projected to minimize cement, which in turn could boost beam structure capacity, serviceability, and cost savings. The goal of this experiment is to look at the load-deflection relationship on RC graded concrete beams of various concrete strengths. The tensile regions of graded concrete beam specimens received a lower strength concrete mix, whereas the compression parts received a higher strength concrete mix. In a structural laboratory, the specimens were tested utilizing a four-point bending method with hinge-roller support. At rupture, the greatest significant beam load capacity was seen in specimens with a quality differential of 20 MPa, which experienced a 14.3% increase in load capacity and a 9.4% reduction in deflection, according to this experimental investigation. Therefore, the bigger the difference in concrete quality between compressive and tensile fibres, the greater the resistance response of the beam in distributing the load into compressive and tensile stress on the cross-section. The most significant deflection reduction pattern was seen in specimens with a higher difference in concrete strength. Finally, the graded concrete can improve the structure's serviceability, particularly the flexural sections, allowing for greater performance constructions. [ABSTRACT FROM AUTHOR]

Since the Covid-19 virus pandemic that hit the world, many activities cannot be done directly and everything has shifted digitally, causing one of them to do activities such as shopping. The phenomenon of shopping for stuff online or digitally is currently one of the hobbies of both men and women to carry out activities that are usually carried out directly by meeting buyers, shopping in this way makes it easier for people to buy and just wait for the desired item to be sent by the seller. However, when making purchases online, there are still many obstacles, such as the stuff received in damaged packaging and the long duration of delivery from the courier, and the delivery of stuff received by the buyer from the courier which can increase the spread of Covid-19. The increasing number of shipments of stuff made by conventional couriers causes environmental pollution to increase because these couriers use trucks that produce air pollution, and this air pollution can also trigger global warming. To reduce the spread of Covid-19 and reduce global warming triggers caused by courier vehicles and anticipate damaged packaging during delivery, courier service delivery parties and sellers can use drones to deliver stuff. This drone moves through the air so that the stuff sent will reach the buyer quickly and reduce direct contact between the courier and the buyer. [ABSTRACT FROM AUTHOR]

Connections are often one of the causes of structural failure. The connection structure using cold-formed steel material has been widely studied using 180°straight rod. This study used type C and 90° upright connection. The test objects were joints in various shapes. This study aimed to determine the tensile strength, length increase, and damage with connection in various shapes. This study consisted of six test object variations; each had three repetitions. The variation consisted of rod built in back-to-back and hollow profiles. The second variation was the connection form, consisting of without lip connection, continuous plate, and elbow plate. The cold-formed steel was formed in an I-shaped letter and pulled using UTM. The obtained results were the greatest tensile strength can be held by the rods which are assembled back to back with L plate connection. Back to back connection of rods affects the tensile strength of CFS rods, even though they have the same cross-sectional area. Connection using L plate produces greater tensile strength and less deformation. [ABSTRACT FROM AUTHOR]

Cobalt oxide synthesis with difference stirring time is rarely highlighted because it is considered to have little effect when, in fact, the stirring time influences the final product. Cobalt oxide has multiple applications since almost all modern technologies that use nanotechnology use cobalt oxide with an easy example is the manufacture of the electrodes in supercapacitors. Cobalt oxide in this study was synthesised using the sol-gel auto combustion method with stirring time variations of 15 minutes, 75 minutes, and 135 minutes. The analysis of phase identification and crystal size used XRD. The morphological analysis used SEM, analysis of functional group bonds used FTIR, and three secondary data were used as amplifiers to determine the specific capacitance value. The smallest crystal size of cobalt oxide in this study was 21.2872 nm at a stirring time of 15 minutes with the final sample having a single phase. The synthesised samples' morphology using the sol-gel auto combustion method appeared to have low agglomeration and porosity levels. Based on the FTIR testing, there was a double absorption peak in the fingerprint region, namely 569–671 cm−1. Based on the three secondary data observed, cobalt oxide's specific capacitance values ranged between 235 F/g, 391.4 F/g, and 430.6 F/g. From this statement, comparing each factor, and the obtained results from other studies, it showed that the synthesised cobalt oxide in this study had the feasibility and potential to be applied in the manufacture of the electrodes of a supercapacitor. [ABSTRACT FROM AUTHOR]

Concrete is the most popular material construction which can be applied in broad construction projects. In addition, concrete is also featured with robust strength, durability, reflectivity, and versatility. However, concrete is prone to rupture that results in decreasing life span and its quality, so it requires additional cost for repair toward its damage. Self-healing concrete is one of the innovations developed by researchers to solve the cracks in concrete allowing the concrete to recover the cracks through the healing process. A self-healing concrete has more superior mechanical properties compared with normal concrete. Self-healing mechanisms can be divided into two types: autogenic and autonomic self-healing. Autogenic self-healing takes advantage of the formation of calcium carbonate crystals from unhydrated cement or mineral particles. Meanwhile, autonomic self-healing uses a healing agent capsulized into microvascular, microencapsulation, and pallets. Researchers applied self-healing concrete on a macro-scale, such as in panel walls, roof slabs, and river floodgates. This paper uses the literature review method to collect the data about self-healing concrete. This study aims to discuss self-healing concrete, its mechanical properties, durability, and analysis of the use of self-healing concrete from multi-perspective disciplines including economy, health and environment, construction, and public policy in Asia's countries. [ABSTRACT FROM AUTHOR]

The usage of aluminium as an alloy has great demands in the construction, aerospace/aircraft, especially in the automotive sector. Almost all frames and engine construction are made of aluminium alloy. The advantages of aluminium include its lightweight metal, corrosion resistance, good electrical conductor, easy integration with other metals, and machinability. Al-Si alloys in the automotive sector, such as conditional pistons are very suitable because of their wear resistance, corrosion resistance, and lightness properties. This study aimed to identify the effect of adding copper to the Al-Si alloy to obtain the Al-Si-Cu alloy, which was expected to provide mechanical strengthening and microstructure from the stir casting process. The mechanical toughness test results showed an increase in toughness at the addition of 1.5 wt% with a value of 0.0977 J/mm2. Simultaneously, the raw material had a value of 0.0707 J/mm2, gradually decreased with the addition that exceeded 1.5 wt%, namely 2.5 wt% addition resulted in a value of 0.0661 J/mm2, and the addition of 3.5 wt% with a value of 0.0578 J/mm2. The formed microstructure showed continuous smaller granules with increasing Cu percentage, while the dendrites had slender characteristics that increased with increasing Cu percentage. [ABSTRACT FROM AUTHOR]

In non-ferrous metals, solution annealing is often known as the method of precipitation hardening. Precipitation hardening is a heat treatment process which consists of two heating processes: the solid solution process and precipitation hardening/ageing. In this study, a heat treatment was carried out using precipitation hardening method with solution treatment at a temperature of 800 °C for 5 hours and precipitation hardening was performed at a temperature of 300 °C with holding time variations of 15 minutes, 30 minutes, and 45 minutes. After, the hardness and microstructure testing was carried out to determine the mechanical properties. This research aimed to obtain the optimal holding time during precipitation hardening method of 44%Cu-27%Zn-23% Nb Zn brass material. The improvement of mechanical properties, especially hardness value, occurred in the brass specimen with a holding time of 15 minutes. The brass's microstructure with precipitation hardening treatment did not change, namely the α + β phase. The changes occurred in the α phase size, decreasing and the emergence of a new β phase in a small size. Thus heat treatment create new precipitate phase namely γ phase as the result of 22% Nb content. As the holding time increases, the size of precipitate will grow larger become the coarse precipitate and reduce the mechanical properties of the specimen especially hardness value. [ABSTRACT FROM AUTHOR]