Fly ash from Coal-Combustion Waste as an Additive for Quality Improvement and Compressive Strength of Cement

A series of tests were carried out to determine the effect of the addition of coal combustion fly ash as an additional mineral (additive) on improving the quality and compressive strength of cement according to the Indonesian National Standard (SNI 15-2049-2004). Research methods include sample preparation, manufacture of cement with 0%, 5%, 8%, 12%, and 15% fly ash variations, chemical and physical properties of cement. The parameters measured were the level of chemical composition (%) using X-Ray Fluorescence Spectroscopy (XRF) ARL 9800 OASIS, free lime content (%) by volumetry, insoluble residue level (%) by gravimetry, compressive strength (kg/cm2), and smoothness cement (cm2/g). The results showed that the addition of fly ash increased the SiO2 content of cement, thereby increasing C3S and C2S compounds which are compressive strength components of a cement. Besides, the addition of fly ash is directly proportional to IR levels, compressive strength, smoothness, and inversely proportional to free lime levels. So the addition of fly ash can improve the quality of cement by increasing chemical components, increasing compressive strength, and reducing cracking or expansion of cement.

Reservoir sedimentation regime analysis: case study of Kedungombo reservoir and Sermo reservoir

The Kedungombo and the Sermo Reservoirs have problems in fulfilling basic services because of sedimentation. Sedimentation that occurs in each of the reservoirs would form a specific reservoir sedimentation pattern that is supposed to be similar because the hydrology and physiography conditions of the reservoir's catchment area are similar. This study aims to determine the dynamics of sedimentation patterns that occur in the dead storage for reviewing the characteristics/sedimentation regime of the two reservoirs. The analysis was carried out by processing bathymetrical data which were processed into a digital terrain model (DTM) using ArcGIS. Furthermore, the storage volume, sedimentation volume, storage percentage, and specific reservoir sedimentation rate are calculated. The results showed that the two reservoirs showed an increase in sedimentation volume each year so that the reservoir characteristic curve shifted from the plan graph. The dead storage capacity of Kedungombo Reservoir is 100% in 1989 to 43% in 2016 and 100% of Sermo Reservoir in 1997 to 58% in 2011. The specific reservoir sedimentation rate, i.e. 0.0031 and 0.0042 million m3/year/km2 for the Kedungombo Reservoir (between 1989 and 2016) and the Sermo Reservoir (between 1997 and 2011) respectively, indicating that the two reservoirs are in the same regime

The Use of Ground Motion Parameters to identify the Liquefaction during a Strong Earthquake in Northern Thailand

This paper presents a ground response analysis to simulate the liquefaction phenomenon during the 2011 Tarlay Earthquake in northern Thailand. The site investigation data and geophysical measurements on 7 sites in northern Thailand were collected. The multi-springs element model was implemented in finite element ground response analysis. Several parameters, such as peak ground acceleration, peak ground velocity, amplification factor, excess pore pressure ratio, were observed. Furthermore, the correlation from the ground motion parameters was generated to estimate liquefaction potential, which was represented by excess pore pressure ratio. The result showed that the excess pore pressure ratio was relatively well correlated with several ground parameters, such as amplification factor, velocity-acceleration ratio, and factor of safety against liquefaction. The results could be also used for the engineering practice in predicting liquefaction potential in Northern Thailand.

Trajectory Stress and Angle Values Correlation to Deep Beams Dimensional Ratio

SNI 2847-2019 defines a deep beam as a structural component that is loaded on one side and supported on the opposite face, allowing compressive components such as struts to form between the loads and supports. It is also stated that the ratio of the net span of the beam to the height of the beam must match the standards (l/h) 4. The goal of this investigation is to determine the value of the stress’s correlation and the trajectory angle to the ratio of the l/beam h's with a span of 4 meters when subjected to a point load of P = 2,000 kN. In the analysis procedure, SAP v.14 is being used to determine the value of stresses and trajectory angles of variations l/h. The results obtained from this study is ratio of l / h of deep beam affects the magnitude of the stress and the angle of the trajectory. Increasingly the width of the beam has no significant effect on the resulting trajectory angle.

Effect of Addition Polypropylene Fiber on Compressive Strength and Permeability Values in Porous Concrete

The infrastructure growth has an impact on reducing green areas, which will be followed by reduced water catchment areas. Porous concrete is one of the porous materials that can be used on a pedestrian walk, which is able to drain water. The porous concrete has a limitation strength. This research aims to determine the effect of using various content of chemical additive and polypropylene fibers for porous concrete mixtures related to the compressive strength and permeability values. This experimental method referring to ACI 522R-10 Standard. That specimens using chemical additives and variations of polypropylene fibers: 0.05%, 0.1%, 0.15%, 0.2%, and 0.25% by weight of cement. The results showed that the specimen which had the highest compressive strength was 16.9 MPa, which was added 0.25% polypropylene fiber. The addition of polypropylene fibers increases the compressive strength value by 5.6%. Based on the compressive strength and permeability graphs, it can be estimated that the optimal content of polypropylene fiber is 0.17% by weight of cement.

Developing Floating Constructed Wetland in Laboratory Scale as Domestic Waste Contaminant Reductor in Urban Waters

Low awareness of sanitation of urban citizens creates negative effects on the environment which varied. The triggering factors of the phenomenon are education and conservation technology. A conservation technology, eco-technology e.g. constructed wetlands, is proposed to solve the problem. Laboratory work is conducted to obtain comprehensive analysis about floating constructed wetland. The research paper aims to illustrate the efficiency performance of constructed wetlands, with domestic species, in the lab-scaled area from urban wastewater. The constructed wetland media is prepared horizontally. The analysis of its performance leads to a discussion of urban water quality. Samplings and laboratory tests are conducted to examine pH, phosphorus, nitrogen, suspended solids, conductivity, COD, and BOD. The benefit of Nasturtium officinale as FTW media reduce phosphate, nitrate, and BOD as 100% in 14 days. The discharge simulation during 14 days reduce TDS and TSS as 100%.

A Note on The Design of Seawall for Tsunami Disaster Mitigation

Many coastal structures or structures in coastal areas were destroyed by a tsunami attack. Such destructions were due primarily to the fact that such structures were not designed to withstand a tsunami. Those which were designed to withstand tsunami force may also have been destroyed due to some damaging factors which were not included in the design. The damage of the coastal structures is one of the important factors that have caused casualties. Especially, when the destroyed structures were originally aimed to mitigate the area against tsunami, they may cause higher fatalities. Examples of such structures are sea walls in many parts of Japan which were destroyed by the 2011 tsunami. This paper discusses the important factors relevant to the damage of seawall as tsunami mitigation structure such as impact force due to tsunami front, hydrostatic force, and hydrodynamic force, debris force and scour due tsunami. The study was carried out based on literature about the damages of seawall as tsunami protection structures and laboratory experiment reports. The destructions to the structures were divided into three classifications namely instantaneous direct destruction due to impact and drag forces, slowly direct destruction due to drag force, and slowly indirect destruction due to scour. Finally, important aspects to be considered in the design of seawall as tsunamis protection were proposed.

Commuters' Behavior in Response to the Policy of Conversion of Paratransit to City Buses in the Bandung City

Bandung City Government plans to improve their bus services which are expected to decline traffic congestion,reduce air pollution, and improve road safety. One of the efforts is to implement the conversion policy of minibus/paratransit to public bus. The purpose of this study is to analyze people's behavior related for theconversion policy above and their intentions to use it. For that purpose, the analysis performed with the datathat obtained by interviewing public transport users in Bandung City. The method used in this research isTheory of Planned Behavior. It is found that, the effect of evaluation outcomes, motivation to comply andperceived power proven to be significant on the behavioral intention to shift the use of public transportationfrom mini public buses to city buses. The contribution of evaluation outcomes influences the highest comparedto other factors, which is 32.36%, this shows that the evaluation of the performance of city bus services is themost dominant factor in shaping the behavioral intention to use city bus. Positive perception towards theconversion policy is in the high number, however, the intentions to shift to public transport should be supportedby ensuring high quality bus services.

Vehicle Trajectory Test on Interlocking Pavement Made From No Fine Agregate Concrete

In rainy season, many cases of roads being submerged in water because of a lack of drainage capacity and low water absorption by the subgrade. This study makes no fine aggregate concrete as an interlocking pavement to increase water absorption to the drainage layer and subgrade. No fine aggregate concrete is made from mix of cement : coarse aggregate = 1 : 6 with water cement ratio 0,4. The results showed the value of specific gravity, water absorption, compressive strength, and Na2SO4 resistance are 1,703 gr/cm3, 2.57%, 10.8 MPa, and 0.79%. To see the level of interlocking pavement performance, no fine aggregate concrete is arranged above the drainage layer and the levelling layer, and then a trajectory and inundation test is performed. The result of inundation and trajectory tests shows that interlocking pavement can pass water to subgrade without inundation and can withstand the wheel loader that is equivalent to 13,000 kg so that it can be used for sidewalks, park lanes, and pavement with a maximum axle load of 8 tons.

Creep Behavior of Open Web Truss Joist Made of LVL Sengon

Laminated Veneer Lumber (LVL) Sengon is classified as one of the engineering products having a significant increase of both physical and mechanical properties compared with Sengon solid wood. Considering its short planting years and sustainable production, Sengon wood is very potential to be used as construction materials of low-rise houses to support the housing needs in Indonesia. Creep behaviour of LVL Sengon material is one of the mechanical properties that needs to be considered. This article evaluated value of creep factor of the open web truss joist (OWTJ) LVL Sengon test and compared this experimental creep factor with the numerical results developed by FE model taking into account the viscoelastic parameters of authors' previous study. The viscoelastic parameters were based on a 217-day creep test of compression and tension parallel to the grain of LVL Sengon at 20 % of stress level that were further modeled using Prony series creep model having n equals to 3. The reduction in the modulus of elasticity over time resulted in creep deflection and creep factor values at 217 days of testing results and FE numerical analysis of the OWTJ LVL Sengon ranging from 1.50–1.54; while the predicted creep factor at 25 years of service life is 1.57 or greater than the creep factor value provided in SNI 7973: 2013 of 1.5.