Pengaruh Penambahan Sika Grout Pada Balok Beton Bertulang Dengan Kondisi Spalling

Grouting merupakan metode perbaikan kerusakan struktur yang sering kali digunakan saat ini karena menerapkan standar corps of engineering CDR C-621 dan ASTM C-1107. Tujuan penelitian ini untuk mengetahui pengaruh penambahan sika grout pada balok beton yang telah mengalami kondisi spalling. Dalam penelitian ini digunakan Sika grout 215 yang mempunyai karakteristik tidak susut, tidak korosif, dan dapat mengalir dengan baik sehingga dapat dengan mudah mengisi bagian-bagian kecil pada beton dimana digunakan benda uji berupa balok beton bertulang dengan dimensi 150 mm x 200 mm x 3300 mm, mutu beton yang digunakan 20 MPa. Benda uji yang dibuat dalam dua variasi yaitu balok beton bertulang tanpa grouting yang berfungsi as balok kontrol diberi simbol BK sebanyak 3 buah. Variasi kedua balok beton bertulang dengan penambahan sika grout pada daerah tarik balok dan diberi simbol BGR sebanyak 3 buah balok. Hasil penelitian menunjukkan beban maksimum balok BGR menurun 47,62% dibandingkan balok BK, hal ini menunjukkan bahwa penggunaan grouting pada balok yang mengalami kerusakan tidak mampu meningkatkan kapasitas kekuatan beton tetapi hanya berfungsi sebagai perbaikan untuk menutupi beton yang mengalami spalling agar bentuknya seperti semula. Hasil uji balok BK menunjukkan bahwa semua balok mengalami kegagalan lentur sedangkan untuk balok variasi mengalami kegagalan debonding

FLEXURAL CAPACITY OF THE PRECAST RC BEAM-COLUMN CONNECTION USING CFRP SHEET

Precast concrete have advantages in quality and shorter construction time. The connection of a precast concrete structures is important for the successful construction. This paper presents an experimental investigation of the flexural capacity of the portal system beam-column connection of precast concrete using CFRP sheet. The study was conducted to develop a connection system using CFRP sheet on a precast concrete frame of a highway bridges. A series of specimens with parameter of CFRP sheet patterns was prepared. A shear key on the column was prepared to support the beams connected to the column. Therefore the CFRP sheet was patched to sustain only the flexural forces occurred on the connection. The CFRP sheet patterns applied were combined with CFRP belt to increase the bonding capacity of the main CFRP sheet. A monolith specimen was also prepared as control specimens. Initially the columns and beams were casted separately to produce a precast concrete. The shear key on the column was strengthened using anchored steel plate. Results indicated that the specimens using CFRP sheet as connection has flexural capacity of approximately 85% of the monolith specimens

KAJIAN EKSPERIMENTAL PADA MIKROSTRUKTUR DAN KEKUATAN BETON YANG MENGGUNAKAN AIR LAUT, PASIR LAUT DAN SEMEN PORTLAND KOMPOSIT SEBAGAI INOVASI TEKNOLOGI UNTUK MENDUKUNG PEMBANGUNAN PULAU-PULAU TERPENCIL

Kendala utama pengembangan budidaya perairan (aqua culture) dan pembangunan infrastruktur di gugusan pulau-pulau terpencil serta daerah pesisir pantai yang lebih rendah dari permukaan air laut (low land) adalah sumber air bersih yang tidak memadai untuk memproduksi beton. Pembuatan kolam dari beton atau pasangan batu yang terbuat dari mortar (semen, air dan pasir) memberikanketahanan (durability) yang tinggi pada kolam untuk budidaya perikanan. Material beton adalah material yang paling banyak digunakan dalam pengembangan infrastruktur. Penggunaan air laut dan pasir laut dalam pembuatan beton bertulang hingga sekarang dibatasi karena mempercepat karat pada besi tulangan dalam beton. Penelitian ini bagian dari inovasi teknologi untuk mengatasi keterbatasan sumber air bersih dan agregat sungai atau gunung. Penelitian ini menggunakan semen Portland Komposit yang merupakan ecosemen dengan unsure limbah seperti abu terbang. Bentuk penelitian adala heksperimental sungguhan (true experimental research) yang dilaksanakan 3 tahun. Penelitian tahun I menitik beratkan pada mix desain, analisa karakteristik mikro struktur dan kekuatan beton yang berorentasi pada optimalisasi air laut dan pasir laut sebagai sumber daya alam nasional. Penelitian tahun ke II dan III melanjutkan uji mikro struktur dan kekuatan, dan secara bersamaan merancang dan menguji pelat beton serta tulangan non korosif yang dapat diimplimentasikan di gugusan pulau-pulau terpencil. Hasil penelitian ini diharapkan menjadi detail rujukan bagi pemangku kepentingan (pemerintah daerah, Dinas Pekerjaan Umum, Lingkungan Hidup dll) untuk mengembangkan budidaya perikanan di wilayah pesisir pulau-pulau terpencil. Penelitian ini juga dapat menjadi salah satu rujukan penggunaan material untuk pengembangan infrastrktur yang memperkuat konektivitas darat dan laut dan memperkuat pembangunan kawasan strategis untuk industry perikanan dan maritim di wilayah Koridor Ekonomi (KE) Sulawesi serta gugusan pulau-pulau berdasarkan Master Plan Percepatan dan Pengembangan Ekonomi Indonesia (MP3EI)

Pengaruh Variasi Jarak Baut Terhadap Perilaku Geser Balok Beton Bertulang yang diperkuat dengan Panel Mortar Geopolimer

Abstrak Penelitian ini menyajikan perilaku balok beton bertulang yang diperkuat dengan panel mortar geopolimer dan serat Polyvinyl Alcohol  (PVA). Benda uji terdiri atas 3 buah balok dengan dimensi 150x300 mm dan panjang 2300 mm. Panel mortar geopolimer dipasang pada bentang geser balok beton bertulang dengan variasi jarak antar baut 200 mm (GM-200) dan 300 mm (GM-300). Hasil penelitian dibandingkan berdasarkan pendekatan beban-lendutan, beban maksimum, perilaku beban regangan tulangan dan beton, dan pola retak. Hasil penelitian menunjukkan bahwa kapasitas geser balok meningkat sebesar 34.98% (GM-W-200) dan 28.81% (GM-W-300) dibandingkan dengan balok kontrol (CB). Selain itu, variasi jarak baut juga berpengaruh signifikan terhadap pola kegagalan balok. Balok dengan jarak antar baut 200 mm menunjukan pola kegagalan lentur dan daktail, sementara balok dengan jarak antar baut 300 mm menunjukan pola kegagalan geser yang getas. Kata kunci: beton bertulang, jarak antar baut , mortar geopolimer, perkuatan   Abstract This study presents the behavior of reinforced concrete (RC) beams strengthened with geopolymer mortar panels and Polyvinyl Alcohol (PVA) fibers. fibers. The specimens consist of three RC beams with dimensions of 150x300 mm and length of 2300 mm. Geopolymer mortar panels are installed on shear spans of RC beams with variations in the distance between the bolts of 200 mm (GM-W-200) and 300 mm (GM-W-300). The study results were compared with the control beam (CB) without strengthening. The shear behavior of the beams was discussed based on the load-deflection behavior, the maximum load, the reinforcement and concrete stress-strain behavior, and the crack pattern. The results indicated that the shear capacity of the strengthened beams increased by 34.98% (GM-W-200) and 28.81% (GM-W-300) compared to the control beam (CB). In addition, differences in bolt spacing had a significant influenceon beam failure patterns. Beams with a bolt sapcing of 200 mm exhibited ductile bendingfailure, whereas beams with a bolt spacing of 300 mm showed brittle shear failure. Keywords: bolt spacing, mortar geopolymer, reinforced concrete, reinforcemen

Performance of Fly Ash Concrete with Nickel Slag Fine Aggregate in the Marine Environment

This research aims to assess the feasibility of the mechanical strength and the durability of the concrete containing 50% nickel slag and a combination of 15% and 30% fly ash with a water-cement ratio of 0.25 and 0.45 in a marine environment. Four types of concrete, namely OPC-sand (C) as control concrete, OPC-50GNS (S), 15FA-50GNS (F1), and 30FA-50GNS (F2) as comparison concrete, were tested with a 100×200 mm cylindrical specimen. The results showed an increase in the mechanical strength and potential resistance of the comparison concrete at the age of 28 days. While at the age of 180 days, fluctuating changes were found. The compressive strength of S concrete increased by 36.9 and 9.3% respectively, F1 concrete by 37.7% and 1.7%, F2 by 33.7% and 5.9% at ratio 0.45 and 0.25. Likewise, the value of the split tensile strength and modulus of elasticity of concrete. This result was followed by reduced porosity, sorptivity, and chloride penetration resistance as an indication of better concrete durability. Fly ash appears to have a greater positive impact on potential durability than mechanical strength at a water cement ratio of 0.25 versus 0.45. Although the chloride penetration resistance is decent, the compressive strength of concrete with a water-cement ratio of 0.45 does not qualify for application in the marine environment. In contrast, concrete with a water-cement ratio of 0.25 containing 50% nickel slag and the addition of class C fly ash up to 30% was declared suitable for application to concrete in the marine environment zone C2 according to ACI 318-19. Doi: 10.28991/CEJ-2022-08-12-010 Full Text: PD

Performance of Retrofitted Square Reinforced Concrete Column using Wire Mesh and SCC Subjected to Cyclic Load

One way to restore or increase the strength of the structure against earthquakes is to use retrofit method and wire mesh is a material that has high prospects as retrofit material. The purpose of this study was to examine the use of wire mesh as a retrofit material on reinforced concrete columns burdened with cyclic loads. In this study, testing of 3 square column samples of reinforced concrete with dimensions of 300  300 mm. The first specimen is fully retrofit on the entire cross-section of the column, the second specimen is retrofitted on the plastic hinge area of the column and the third specimen is a control column without retrofit. In the first and second specimens were retrofitted with wire mesh size M6 using SCC which was then tested with a cyclic load using displacement control method based on the provisions stipulated in the Indonesian Standard SNI 7834:2012. From the test results and analysis results, it was found that the capacity and ductility of displacement in retrofit specimens increased significantly compared to specimens that were not retrofit. In addition, the decrease in stiffness in retrofit specimens was smaller than in non-retrofit specimens. As for the value of energy dissipation in fully retrofit specimens and in retrofit on the plastic hinge area is almost close. Based on these conditions, the use of wire mesh size M6 and SCC can be used as retrofit material on the column that is burdened with cyclic load. Doi: 10.28991/cej-2021-03091685 Full Text: PD

Flexural and Shear Behaviour of Reinforced Concrete Slab With PVC Pipe as A Cavity Forming in Two-Way System

Piping modifications Polyvinyl Chloride as forming a hollow cavity in the concrete slab is one alternative to reduce the self-weight of structure. The placement of PVC pipe that has been modified on the concrete tensile area is expected not to reduce the bending strength of the plate. In the study, the analysis was compared to reinforced concrete slab massive (PB-1) with a hollow reinforced concrete slab PVC (PB-2) with the same thickness and compared well with hollow reinforced concrete slab PVC (PB-3) with an equal volume of the concrete slab massive reinforced (PB-1). All test objects have the same dimensions, including the number and spacing of reinforcement. The analysis method of the moment coefficient obtained flexural strength of PB-1 amounted to 328.175 kN, plate PB-2 amounted to 329.624 kN, and the plate of PB-3 amounted to 387.184 kN. While the results of the analysis using the Navier method deflections values obtained for the plate PB-1, PB-2, and PB-3 are 0.0948 mm, 0.33952 mm, and 0.04267 mm, respectively. Shear forces values for plate PB-1, PB-2 and PB-3 is 965.908 kN, 231.818 kN and 281.429 kN respectively

Effect of Bonding Area on Bond Stress Behavior of GFRP Bars in Concrete

The application of Glass Fiber Reinforced Polymer (GFRP) bars is suitable for concrete structures that are susceptible to corrosion, owing to their corrosion-resistant characteristics. Therefore, it is feasible to reduce the concrete cover on reinforced concrete beams by utilizing GFRP bars. However, this can reduce the bonding strength between GFRP bars and concrete. Therefore, this study aims to investigate the bonding behavior between GFRP bars and concrete as a preliminary test for structural applications. The bond stress behavior between GFRP bars and concrete was analyzed by 18 pull-out tests. The test specimens comprised GFRP bars with three different variations, namely GFRP bars with concrete cover (GFRP-C), GFRP bars without concrete cover (GFRP-E), and GFRP bars with a complete wrapping of GFRP sheet (GFRP-C-Sheet). The bond stress-slip curve, bond strength, and failure pattern were utilized to analyze the effect of each variation. The research results indicate that the bonding stress between GFRP bars and concrete was strongly influenced by the concrete cover, where the bonding strength decreased by 65%. Nevertheless, the utilization of a complete wrapping GFR) sheet resulted in a 26.4% increase in bonding stress. The present study has identified three distinct modes of failure, including pull-out (GFRP-C), concrete crushing (GFRP-E), and GFRP sheet debonding (GFRP-C-Sheet). Doi: 10.28991/CEJ-SP2023-09-010 Full Text: PD