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study of labor cost escalation in delay projects

Journal of Physics: Conference Series 2020年第1期1469卷

作者： R Natawidjana S Nurasiyah Civil Engineering Study Program Universitas Pendidikan Indonesia Bandung Indonesia

Timeliness of implementation is one of the variables in the implementation of construction projects. Evaluation and acceleration of delays projects will generally affect the use of project resources. Project delays can be overcome by making efforts, among others, with the Crashing Method which will affect various alternative costs resulting from Crashing. This study aims to understand that the delay in the construction project schedule will have an impact on the new schedule and the impact of costs that occur due to the acceleration carried out so that the project life is in accordance with the plan. Furthermore, it was analyzed for the need for additional workforce groups or only to maintain the addition of overtime. This research was conducted with descriptive analytic method, which is a research that will explain the conditions in the field in detail about project schedule delays by analyzing the magnitude of escalation of labor costs due to the acceleration of the duration of each activity so that the project schedule returns to the plan age.

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Mechanical properties of self-compacting concrete incorporated with high volume fly ash

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IOP Conference Series: Materials Science and engineering 2020年第1期821卷

作者： M Solikin T Mulyanto Study Program of Civil Engineering Universitas Muhammadiyah Surakarta Surakarta Indonesia

Self-compacting concrete (SCC) is beneficial in concrete casting process as it does not need any tools for consolidation process. In addition, the utilization of High content fly ash in has proven in improving mechanical properties of concrete although the slow strength development is an issue to coop with. This paper presented an experimental program on the mechanical properties test of high strength self-compacting concrete incorporated with high content fly ash. The mix proportion for the concrete was prepared based on ACI high strength concrete with the design strength of 45 MPa. The mechanical properties test consists of slump flow test, compressive strength test development, flexural strength test and water absorption test of concrete. The slump flow test was tested for fresh concrete and the strength development test was tested at the age of 14, 28 and 56 days. In addition, test for flexural strength specimen and absorption specimens were tested at the curing age of 56 days. Moreover, the high strength normal concrete specimen was prepared as control mix design. The result shows, less water was need to reach design flowability for Self-Compacting Concrete High content fly ash concrete and it gives impact to lower water absorption for the type of concrete. In addition, at the curing age of 56 days the compressive strength of high strength high content fly ash-self compacting concrete was comparable to the normal concrete.

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Impacts Due to Foundation Piling Work

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Journal of Physics: Conference Series 2021年第1期1726卷

作者： O L Sari A A I Saputra A Subhakti A P Putri C C S Khala Civil Engineering Study Program Kalimantan Institute of Technology Balikpapan Indonesia

The foundation erection work is a job that has a high enough complexity. In making the decision of the type of pile and the method of erection, practitioners have many choices with various conditions in the field. Decision making will result in an impact during the foundation erection process. This study aims to analyze what are the impacts caused by the choice of pole type and piling method. A preliminary survey was conducted together with four experts to verify and reduce the 11 impact indicators obtained from the literature study, obtained 6 impact indicators which are quite relevant according to experts and will be used in the questionnaire survey. The questionnaire survey was conducted on 45 practitioner respondents who had carried out foundation building work. Data analysis validity and reliability tests were carried out on the questionnaire data. It was concluded that there were three main impacts that occurred due to the choice of the type of foundation pile and the piling method, namely environmental impact, economic impact, and social impact. The main impacts are broken down into six impacts including the use of fuel, ground vibration, fuel and material costs, equipment and labor costs, workplace safety, and noise.

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Effect of Additive Chemicals on Soil Characteristics

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Journal of Physics: Conference Series 2020年第5期1477卷

作者： Encu Sutarman Widjajani Estiyan Dwipriyoko Civil Engineering Study Program Engineering Faculty Universitas Langlangbuana Bandung Indonesia Industrial Engineering Study Program Engineering Faculty Universitas Langlangbuana Bandung Indonesia Informatics Study Program Engineering Faculty Universitas Langlangbuana Bandung Indonesia

The occurrence of landslides in the hills of Walahir, Kidang Pananjung village, Cililin subdistrict. Bandung in May 2004 needed attention and research so that the causes of the landslide could be identified. This landslide took many lives and property, heaped around 5 hectares of rice fields and residents' villages below and claimed 15 lives. Based on geotechnical investigations, the slip plane is at a depth of 4 meters from the ground surface and the area of the landslide ranges from 30,000 m2 leaving weathered rock beneath. Is the opening of agricultural land and fields followed by the use of chemical fertilizers is one of the causes of landslides? This study aims to determine the effect of a single chemical fertilizer (Urea, Za, SP36) and compound (Green Giant NPK, MKP) on the soil under conditions of optimum water content and water saturation or soaked which are carried out at the Chemical Laboratory of the Department of Energy and Mineral Resources of Bandung and Mechanics Laboratory Bandung Institute of Technology. Research on the influence of chemical fertilizers which is carried out using percentages of 1%, 2% and 3% with a relatively short ripening time intends to analyze the extent to which chemical fertilizers have an effect. Research is limited to the identification of minerals and chemical elements of original soil, soil physis properties, Atterberg boundaries, soil index properties, soil classification, soil elastic modulus. Hypothesis; The chemical content of fertilizers in the soil causes changes in soil characteristics. The method of taking original soil is by drilling original soil around the area where landslide disaster occurred at the same height as the height of the landslide slope, soil samples taken from depths of 1 meter and 3 meters from the surface of the land or the base layer between soil and rocks based on ASTM D-1452, 1587, 1586. Laboratory data from the original soil and chemical soil mixture of fertilizers is needed as input data for

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The potency of metakaolin as addition material in high strength self-compacting concrete to increase Modulus of Rupture (MOR) in rigid pavement application

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IOP Conference Series: Earth and Environmental Science 2021年第1期700卷

作者： W Wibowo E Safitri A Setyawan Y Muslih A Mediyanto B Setiawan T R Syaufina Civil Engineering Study Program Universitas Sebelas Maret Surakarta Indonesia

This study focused on the modulus of rupture (MOR) for high strength self-compacting concrete (SCC) using varied metakaolin (MK) composition. The MOR significantly contributes to the resilience and mechanical performance of the rigid pavement, and is enhanced by modifying the regular concrete material. In addition, the MK is known to be potentially economical and occurs abundantly as natural resources. Plain concrete beams with dimensions 400 x 100 x 100 mm3, were tested in the laboratory in an effort to measure the MOR from varied MK composition for each specimen or modified concrete type. The result showed the MOR increase is exclusively as a result of additional metakaolin. Also, the newly modified material was proven to offer more advantages when applied as rigid pavement material. Furthermore, the analytical laboratory result showed the optimum MK dosage was estimated at 20% of the binder weight. This subsequently enhances the MOR by 17.28% compared to non-MK concrete.

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A study on Durability for Rigid Pavement Against Acid Environment and Displacement Model

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IOP Conference Series: Materials Science and engineering 2021年第1期1144卷

作者： Wahyu Widodo Civil Engineering Study Program Faculty of Engineering Universitas Muhammadiyah Yogyakarta Indonesia.

An acidic environment commonly found in peat soils or expansive soil will harm the quality of rigid pavement by considering its use at long-life plan, traffic load, and minimization of damage to the crossroad due to vehicle braking. As a concrete provider, chemical admixture as mixed materials today is widely used with the reasons of workability, initial strength, as well as saving of material used. This research aimed to find out the durability of concrete admixture using sika-NN and plastocrete (retarding and water reducing admixture) at the acid environment and knowing the displacement that occurred using ABAQUS software modeling. It used the laboratory experimental method and the cube concrete sample 15×15×15 cm with the compressive strength of 33.2 MPa. A total of 18 concrete samples were immersed using normal pH water and H2SO4 at pH 1 ± 1 tested at 3, 7, 14, 28, 60, and 90 days using the Duplo method. In this research, the concrete durability was carried out using, Ultrasonic Pulse Velocity Test (UPVT) to test the density, compressive test, and modeling concrete displacement on peat soils with vehicle loads in acidic environments using software ABAQUS. The mixed design results show an average setting time value of about 112 minutes. Coarse aggregate and cement decrease due to additives is approximately 24% and 18% respectively, increasing the use of fine aggregate to 16.49%, but the value of concrete density increases base on soaking time. Besides that, there is a decrease in compressive strength up to 16% at the age of 90 days. The value of displacement in the modelled pavement uses a maximum load of 8 tons each 2.994 mm for concrete with normal water and 3.045 mm for concrete with an acid environment respectively. Concrete soaked in acid water is the greatest deformation that occurred in rigid pavement using ABAQUS and indicates that acid water has an impact on decreasing concrete quality.

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The effect of mixing ratio variation of sludge and organic solid waste on biodrying process

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IOP Conference Series: Earth and Environmental Science 2018年第1期106卷

作者： A C Nasution G A Kristanto Civil Engineering Department Environmental Engineering Study Program Universitas Indonesia Depok Indonesia

In this study, organic waste was co-biodried with sludge cake to determine which mixing ratio gave the best result. The organic waste was consisted of dried leaves and green leaves, while the sludge cake was obtained from a waste water treatment plant in Bekasi. The experiment was performed on 3 lab-scale reactors with same specifications. After 21 days of experiment, it was found that the reactor with the lowest mixing fraction of sludge (5:1) has the best temperature profile and highest moisture content depletion compared with others. Initial moisture content and initial volatile solid content of this reactor's feedstock was 52.25% and 82.4% respectively. The airflow rate was 10 lpm. After biodrying was done, the final moisture content of the feedstock from Reactor C was 22.0% and the final volatile solid content was 75.9%.The final calorific value after biodrying process was 3179,28kcal/kg.

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Comparison of copper adsorption effectivity in acid mine drainage using natural zeolite and synthesized zeolite

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IOP Conference Series: Earth and Environmental Science 2020年第1期473卷

作者： E Wulandari A E Hidayat S S Moersidik Department of Civil Engineering Environmental Engineering Study Program Universitas Indonesia Depok Indonesia

Acid mine drainage (AMD) contains a high concentration of various heavy metals and have low pH levels. In this study, the comparison between the use of natural zeolite and synthesized zeolite for Cu2+ removal in AMD was conducted. The adsorbent of natural zeolite was prepared through a chemical activating method by adding NaOH. While, synthesized zeolite was made from coal fly ash using a two-step method, fusion, and hydrothermal process. The AMD used in this study was artificially designed with the concentration of Cu2+ 100 ppm and pH ± 3. The adsorption experiment was carried out using a batch method to observe the influential parameters such as adsorbent dosage, contact time, adsorbent isotherms, and kinetics. The result show that the removal efficiency of Cu2+ for natural zeolite and synthesized zeolite was 98,16% and 93,98 % with optimum adsorbent dose 1,5 g/l and 21 g/l, respectively. The optimum contact time for both adsorbents was 120 minutes. The Langmuir isotherm model fitted the adsorption for synthesized zeolite and natural zeolite, with the maximum sorption capacity of 23,8 mg/g and 30,03 mg/g, and the kinetics model of pseudo-second-order and pseudo-first-order. The result of this study that the good adsorption effectivity synthesized zeolite. Furthermore, both natural zeolite and synthesized zeolite have great potential as a sustainable and economical material for heavy metal removal ion Cu2+ in wastewater.

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Life cycle assessment analysis of empty fruit bunches utilization: A case study in Riau province

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AIP Conference Proceedings 2024年第1期3215卷

作者： Ayu Wulandari Djoko Mulyo Hartono Astryd Viandila Dahlan Environmental Engineering Study Program Department of Civil Engineering Universitas Indonesia Depok Indonesia

Palm oil consumption has risen due to an increasing preference for vegetable oil. However, this growth in the palm oil industry has given rise to various challenges, especially concerning environmental issues and emissions. This study evaluated the ecological consequences of using empty palm fruit bunches in plantations and furnaces and utilizing solid waste from empty fruit bunches as a renewable energy source. The research findings indicate that, for a 30 tons/hour capacity, the total greenhouse gas emissions (GWP) in the furnace and plantation management amount to 234.72 kg CO2 eq and 234.69 kg CO2 eq, respectively. The acidification impact (0.51 kg SO2 eq) and the eutrophication (0.95 kg PO4 eq) in the plantation and the furnace. For a 60 tons/hour capacity, the total GWP increases to 328.59 kg CO2 eq in the furnace and 328.37 kg CO2 eq in the plantation. Furthermore, acidification (0.73 kg SO2 eq) and eutrophication (1.33 kg PO4 eq) impacts persist in both the plantation and furnace stages. The primary concern highlighted in this research is furnace management, particularly concerning the oil content. Additionally, the production stage emphasizes the importance of raw materials as another critical hotspot. The study recommends implementing technological changes and adopting preventive maintenance practices to minimize the oil content in empty fruit bunches to mitigate the environmental impact during crude palm oil (CPO) production stages; utilizing empty fruit bunches as renewable energy presents an option to reduce greenhouse gas emissions.

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On the delay factors of the private construction projects in Medan city

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IOP Conference Series: Earth and Environmental Science 2018年第1期126卷

作者： A. Perwira Mulia Tarigan Subroto Teaching Staff Post Graduate Study Program of Civil Engineering Universitas Sumatera Utara Former Graduate Student Post Graduate Study Program of Civil Engineering Universitas Sumatera Utara

The delay in construction projects undertaken by contractors is impeding the economic growth of a region. Medan city which is one of the big cities in Indonesia is suffering from it. This study aims to identify the dominant factors causing delays in construction projects conducted by private contractors. The interview method with questionnaires is used to involve 20 contractors, 10 consultants, and 10 owner representatives in the study. From the 45 identified factors causing delays, the highest ranking is the change of work demand by the project owners with 71.84% importance index.

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