Study for determination of coefficient of thermal expansion of concrete at early ages

ABSTRACT Two active mechanisms producing self-induced stresses in immature concrete have been identified as a result of thermal and non-thermal deformations. The thermal stress generated from thermal deformation is commonly estimated considering the temperature increase on concrete elements multiplied by the coefficient of thermal expansion of concrete. Various different values for coefficient of thermal expansion, generally expressed as \u27a \u27, have been reported ranging from 6 to 32 µs/°C. The experimental work in the present study yields a value of a of 10.8 ge/C. This resulted value confirms with those suggested in the codes (BS 8007, BS 8110, Eurocode, ACI). Furthermore, the result also implies that the value of this coefficient considers the total strain, where the strain still incorporates the influence of drying and autogenous shrinkage, not solely the influence of thermal strain. The variety of the reported values of a at the earlier stages of hardening concrete might be attributed to the nature of experimentation adopted in the research

PENGARUH SUBSTITUSI BAHAN PENGISI NANO HYDRATED LIME TERHADAP PERANCANGAN CAMPURAN ASPHALT CONCRETE-WEARING COARSE

Abstract   Asphalt Concrete-Wearing Coarse (AC-WC) is the top layer of a flexible pavement structure. As a road surface layer, the AC-WC coating is very susceptible to moisture damage due to weather influences. Therefore, the use of hydrated lime has been widely studied to improve the performance of asphalt pavements. In this study, the use of hydrated lime, with a finer size or nano scale, is used as a substitute for filler in the AC-WC mixture, with the aim of evaluating the use of nano hydrated lime as a substitute for filler in the AC-WC mixture. This study shows that the use of nano hydrated lime filler substitution in the AC-WC mixture increases the optimum asphalt content value of the mixture along with the addition of nano hydrated lime.   Keywords: flexible pavement; nano-hydrated lime; quenched lime; fillers; asphalt pavement     Abstrak   Asphalt Concrete-Wearing Coarse (AC-WC) merupakan lapisan paling atas dari struktur perkerasan lentur. Sebagai lapis permukaan jalan, lapisan AC-WC sangat rentan terhadap kerusakan akibat kelembaban karena pengaruh cuaca. Oleh karena itu, pemanfaatan kapur padam (hydrated lime) telah banyak diteliti untuk meningkatkan performa perkerasan beraspal. Pada penelitian ini pemanfaatan hydrated lime, dengan ukuran yang lebih halus atau dengan skala nano, dimanfaatkan sebagai subtitusi bahan pengisi pada campuran AC-WC, dengan tujuan untuk mengevaluasi penggunaan nano hydrated lime sebagai subtitusi bahan pengisi pada campuran AC-WC. Studi ini menunjukkan bahwa penggunanaan subtitusi bahan pengisi nano hydrated lime pada campuran AC-WC meningkatkan nilai kadar aspal optimum campuran seiring dengan penambahan nano hydrated lime.   Kata-kata kunci: perkerasan lentur; nano hydrated lime; kapur padam; bahan pengisi; perkerasan beraspa

Perilaku Lentur Panel Beton Semi-Precast pada Daerah Lapangan Tanpa Metode Perkuatan Elemen Pracetak: Tinjauan pada 1, 2 dan 3 Panel

A slab where only the lower portion of the floor slab is prefabricated and receives the top layer of floor slab which is cast in situ, in the context of this research is called semi-precast. For small projects, the transportation, storage, and installation of precast units can be a problem. There will be more problem if it is located in congested urban area. For this reason, precast slab panel system in smaller size and weight was introduced. The precast concrete element which is has a rough surface was predicted capable to act as composite, although no shear reinforcement method was used. The objective of this research is to study the characteristic behavior of semi-precast panel without shear reinforcement method on its interface. The characteristic investigated includes flexural capacity, stiffness, ductility, and failure mode of the slab. In this study, the specimens were divided into two groups. The first group is monolith slab that consists of one, two, and three panel(s). Each panel has 120 mm thickness, 3000 mm span length, and 200 mm width of concrete slab. The second group is semi-precast slab that consists of one, two, and three panel(s). Each panel has 70 mm thick precast slab that serves as formwork for 50 mm in situ concrete layer, to form a 120 mm thick of concrete slab. Dimension and shape between semi-precast and monolith slabs are identical. All specimens were tested under static load and failure load. Experimental results revealed that the stiffness of semi-precast slabs is lower than the monolith slab. More number of panels reduced stiffness differences between semi-precast and monolith slab. It also increases the value of stiffness and flexural capacity of the slabs. The failure mode and crack pattern is classified as flexure. Existence of interface plane which is using no shear reinforcement method can decrease the value of stiffness and flexural capacity of the slab. From the results, it is shown that the slip occurred on the semi-precast slab’s interface. It is predicted that the slip was due to the influence of no shear reinforcement on the interface

PEMODELAN NUMERIK KAPASITAS LENTUR BALOK BETON DENGAN PENULANGAN SERAT BERPOLIMER

Aplikasi Fiber Reinforcement Polimer (FRP) sebagai tulangan menjadi salah satu inovasi baru untuk sistem beton bertulang. FRP atau serat berpolimer merupakan material dengan sifat elastis dan mempunyai kuat tarik yang lebih tinggi dibandingkan baja. Selain mempunyai kelebihan sifat mekanika, FRP juga memiliki sifat tahan korosi, dan sifat non-magnetik, yang dapat memperlambat deteriorasi material akibat lingkungan. Pemodelan balok bertulangan FRP secara numeris dengan finite element perlu dibuat untuk menggantikan pengujian ekseperimental. Dalam penelitian ini dilakukan pemodelan elemen balok lentur dengan perangkat lunak ABAQUS CAE. Dimensi balok 150 mm x 100 mm, panjang 2400 mm dengan tulangan memanjang jenis glass fiber reinforcement polimer (GFRP) tekan dan tarik masing - masing 2D10 dan sengkang D4-100 dengan pembebanan statik  four point loading.  Dalam pemodelan digunakan interaksi perfect bond antara GFRP dan beton sekelilingnya. Untuk validasi pemodelan, kurva beban - defleksi hasil pemodelan dibandingkan dengan kurva beban – defleksi hasil pengujian eksperimental sebelumnya. Hasil model tervalidasi relatif baik dibandingkan hasil eksperimental. Dengan hasil pemodelan yang sudah tervalidasi, beban maksimum model numerik dibandingkan dengan analisis kapasitas lentur nominal SNI 8970 : 2021 sehingga didapatkan rasio perbandingan kapasitas nominal dan beban maksimum model numerik. Diagram beban-defleksi di awal sangat dekat, dengan selisih beban ultimit pada model dengan hasil pengujian lentur balok 12,1%. Perbandingan kapasitas lentur nominal bertulangan GFRP berdasarkan SNI 8970:2021 dan beban maksimum model numerik diperoleh 0,5, aman digunakan sebagai acuan perencanaan balok beton bertulangan

NUMERICAL MODELING OF APPLIED NEAR-SURFACE MOUNTED ON REINFORCEMENT SLAB WITH ABAQUS CAE

Reinforced concrete (RC) is the most applied material in modern construction. Research on strengthening RC concrete members has also been widely carried out. Over time, concrete elements might deteriorate due to several factors, such as load, creep, or any other environmental aspects, leading to stiffness or strength reduction. Following the rapid development of studies on RC, the development of strengthening of concrete structure Reinforced Polymer (FRP) is also the case to overcome concrete deterioration. To improve the strength capacity of the concrete beams, Ega (2020) investigated the effect of epoxy adhesive length on the bonding strength of rebar using several laboratory tests. The result of the study yielded that the optimum length for the epoxy was 150 mm with a strength increase of up to 165.3%. The laboratory tests were modeled numerically using Abaqus CAE to simulate the behavior of the RC beam. Investigating the ideal mesh size and crack model behavior was the first stage of modeling. An RC beam previously experimentally tested by Ega (2020) was used for validation. Therefore, this research compares the numerical results from the Abaqus simulation with experimental data results. The specimen tested for this research was a concrete beam of 1200 mm x 450 mm x 120 mm subjected to 3-point loading. This study aims to develop a suitable numerical model for one of the tested beams and facilitate the design of NSM that follows the character of the previous research

An Analysis of Energy Consumption in the Campus Building’s Operation (Case Study: The Building of Faculty of Engineering and Department of Civil and Environmental Engineering, Universitas Gadjah Mada)

Energy Consumption Intensity (IKE) is an indicator that is used to determine the amount of energy used per area by an air-conditioned building within a month or a year as a reference to determine how much energy conservation can be done in the building. To determine the energy consumption of buildings and to determine the savings opportunities, there should be an effort to review the energy consumption through energy audits. In this research, energy consumption analysis was conducted at the Main Office building of the Faculty of Engineering (KPFT) and Department of Civil Engineering and Environmental (CEED) of UniversitasGadjah Mada Yogyakarta. The analysis was conducted on the main variables of energy efficiency, namely: measurement of temperature and relative humidity, calculation of Overall Thermal Transfer Value (OTTV) and Roof Thermal Transfer Value (RTTV), calculation of Energy Consumption Intensity (IKE) in air-conditioned and non-air-conditioned rooms as well as an analysis of opportunities to increase the efficiency of energy consumption in the buildings.The results showed that the temperature and the relative humidity of the KPFT building = 28.4℃ and 62%, while CEED Building = 28.4℃ dan 65%. Calculation of average OTTV of the KPFT building = 17.61 W/m2 and CEED building = 43.05 W/m2. Average IKE of the KPFT building in 2015 was 3.25 kWh/m2/month and in 2016 was 3.45 kWh/m2/month, while the average IKE of CEED building in 2015 was 1.5 kWh/m2/month and in 2016 was 0.79 kWh/m2/month. Based on the calculation of IKE in both buildings, they are still considered in the category of efficient. However, based on the measurement of temperature and relative humidity, it shows that in both buildings air conditioning is still necessary to achieve the level of thermal comfort, therefore an increase of efficiency in the load is needed to avoid wastage

Base Course Stabilization Performance Using Fly Ash-Based Geopolymers and Their Effect on Water Quality Standards

The road is the main gateway to human life and links essential access points. Some structure pavement failures happened due to the base layer's instability. Fly ash has been used in several parts of pavement structures to increase stability. One significant concern with using fly ash in base course stabilization is its proportion and potential impact on water quality standards. This research aimed to evaluate base course stabilization performance using fly ash-based geopolymers, as well as assess their impact on water quality standards. Materials in this study consisted of aggregate, fly ash, water, and alkaline reagent solutions. The variation of mix considered with a variety of alkaline reagents, namely without alkaline reagents, 3 mol, 6 mol, 9 mol, and 12 mol of NaOH. The ratio between NaOH and Na2SiO3 is 1:2. The use of fly ash in the class A aggregate base course layer has not been able to meet specifications. However, by providing 9 mol of alkaline reagent, the strength of the mixture increases so that the CBR value meets the specifications due to geopolymer bonding. When the alkaline reagent solution becomes more concentrated, the optimum water content decreases, and the bond between aggregates strengthens. The effect of alkaline reagents on water quality standards increases the acidity (pH) value, while other parameters such as BOD, COD, and TSS still meet the standards. This research point to another practical approach that is effective in the field to increase the stability of the base course layer and is environmentally friendly

GEOMETRIK TEMPAT PARKIR PESAWAT UDARA BANDAR UDARA FATMAWATI SOEKARNO DI KOTA BENGKULU

Abstract   Flight services at Fatmawati Soekarno Airport, located in Bengkulu City, continue to develop, along with the increasing public need for air transportation. The increasing need for aviation services affects the number and types of aircraft required. Aircraft maneuvering and parking affect the dimensions of the aircraft parking space. In this study, an analysis of the dimensions of the apron at Fatmawati Soekarno Airport was carried out, with a service life of 20 years. The analysis in this study was carried out using the design aircraft B737-900ER. The existing apron dimension lot is 475 m long and 80 m wide. By using the International Civil Aviation Organization method and the Federal Aviation Administration method, to accommodate aircraft movements for the next 20 years, an apron with a length of 475 m and a width of 100 m is required. Thus, the width of the existing apron must be increased by 20 m, in order to be able to serve the B737-900ER aircraft until the service life of the next 20 years.   Keywords: airport; flight services; apron; air transport.     Abstrak   Layanan penerbangan di Bandar Udara Fatmawati Soekarno, yang terletak di Kota Bengkulu, terus mengalami perkembangan, seiring dengan meningkatnya kebutuhan masyarakat akan transportasi udara. Peningkatan kebutuhan akan layanan penerbangan tersebut memengaruhi jumlah dan jenis pesawat udara yang diperlukan. Pesawat udara yang melakukan manuver dan parkir memengaruhi dimensi tempat parkir pesawat udara. Pada studi ini dilakukan analisis terhadap dimensi tempat parkir pesawat udara di Bandar Udara Fatmawati Soekarno, dengan umur layanan 20 tahun. Analisis pada studi ini dilakukan dengan menggunakan pesawat udara rencana B737-900ER. Tempat parkir pesawat udara eksisting mempunyai panjang 475 m dengan lebar 80 m. Dengan menggunakan metode International Civil Aviation Organization da metode Federal Aviation Administration, untuk melayani pesawat udara hingga 20 tahun mendatang diperlukan tempat parkir pesawat udara dengan panjang 475 m dan lebar 100 m. Dengan demikian lebar tempat parkir pesawat udara eksisting harus ditambah 20 m, agar dapat melayani pesawat udara tipe B737-900ER hingga umur layanan 20 tahun mendatang.   Kata-kata kunci: bandar udara; layanan penerbangan; tempat parkir pesawat udara; transportasi udara

GEOMETRIK TEMPAT PARKIR PESAWAT UDARA BANDAR UDARA FATMAWATI SOEKARNO DI KOTA BENGKULU

Abstract   Flight services at Fatmawati Soekarno Airport, located in Bengkulu City, continue to develop, along with the increasing public need for air transportation. The increasing need for aviation services affects the number and types of aircraft required. Aircraft maneuvering and parking affect the dimensions of the aircraft parking space. In this study, an analysis of the dimensions of the apron at Fatmawati Soekarno Airport was carried out, with a service life of 20 years. The analysis in this study was carried out using the design aircraft B737-900ER. The existing apron dimension lot is 475 m long and 80 m wide. By using the International Civil Aviation Organization method and the Federal Aviation Administration method, to accommodate aircraft movements for the next 20 years, an apron with a length of 475 m and a width of 100 m is required. Thus, the width of the existing apron must be increased by 20 m, in order to be able to serve the B737-900ER aircraft until the service life of the next 20 years.   Keywords: airport; flight services; apron; air transport.     Abstrak   Layanan penerbangan di Bandar Udara Fatmawati Soekarno, yang terletak di Kota Bengkulu, terus mengalami perkembangan, seiring dengan meningkatnya kebutuhan masyarakat akan transportasi udara. Peningkatan kebutuhan akan layanan penerbangan tersebut memengaruhi jumlah dan jenis pesawat udara yang diperlukan. Pesawat udara yang melakukan manuver dan parkir memengaruhi dimensi tempat parkir pesawat udara. Pada studi ini dilakukan analisis terhadap dimensi tempat parkir pesawat udara di Bandar Udara Fatmawati Soekarno, dengan umur layanan 20 tahun. Analisis pada studi ini dilakukan dengan menggunakan pesawat udara rencana B737-900ER. Tempat parkir pesawat udara eksisting mempunyai panjang 475 m dengan lebar 80 m. Dengan menggunakan metode International Civil Aviation Organization da metode Federal Aviation Administration, untuk melayani pesawat udara hingga 20 tahun mendatang diperlukan tempat parkir pesawat udara dengan panjang 475 m dan lebar 100 m. Dengan demikian lebar tempat parkir pesawat udara eksisting harus ditambah 20 m, agar dapat melayani pesawat udara tipe B737-900ER hingga umur layanan 20 tahun mendatang.   Kata-kata kunci: bandar udara; layanan penerbangan; tempat parkir pesawat udara; transportasi udara