This paper presents the findings of an experimental study to investigate the structural behavior of reinforced concrete (RC) beams externally strengthened with various types of kenaf fiber reinforced polymer composite laminates with 50% fiber volume content. The experimental parameters including flexural strength, stress-strain relationship, deflection, tensile stress and young modulus of beams strengthened by different kenaf fiber reinforced polymer composites are discussed. In order to test the flexural strength of the RC beams, a total of eight beams divided into two series were used. In each series, every two of the beams were strengthened with kenaf/epoxy, kenaf/polyester, and kenaf/vinyl ester composite laminates respectively. The remaining two were kept as control specimens. The experimental moment capacity of each beam was calculated using tensile strength and young modulus of the composites. Comparisons were made on the load-deflection, strain behavior and failure mode. Moreover, theoretical moment capacity of each beam was calculated using conventional formulation to verify experimental results. The research findings indicated that all strengthened beams improved structural performance where the maximum flexural strength increase by 40% and maximum deflection reduced by 24%.

The deterioration of concrete structures is a matter of critical concern as it threatens the durability and strength of concrete structures. Kenaf fibrous concrete composite (KFCC) can be used with advantage in new structures such as precast elements, as well as the strengthening, repair and rehabilitation of old structures to improve their durability properties. These structures are composite components, with parts as Plain concrete (PC) and others as KFCC. This study, therefore, investigated the interfacial bonding behaviour between KFCC and PC. Shear, tensile and compressive tests were carried out to measure the bond strength in shear, direct tension and compression respectively for PC to PC, PC to KFCC and KFCC to KFCC interface. Three different types of concrete grade (25, 35, and 45 MPa) were produced for the KFCC and one type of concrete grade (35 MPa) for the substrate PC. The outcome of the test showed that KFCC had an excellent interlock with the surface of the PC substrate, and thus, gives bond strength greater than the strength of PC. New concrete with the highest concrete grade of 45 MPa ensued in high compressive, tensile and shear bond strength.

No abstract

Abstract. The development of geopolymers has allowed the flash as the substitution of cement in the application of concrete. Therefore, this will be very useful considering the quite abundant by-product materials from power plants burning coal in South Sumatera. However, the untreated fly ash from the source caused its fineness level unpredictable, whereas the fineness of binder in cementitious material significantly affects the mechanical properties of the harden. Therefore, this study aims to determine the contribution of the fineness level of fly ash to the compressive strength of geopolymer mortar, as well as its excellent composition. Type F fly ash from Tanjung Enim Power Plant was treated by filtering to obtain different fineness levels based on the fall zones of the ash. Activators used in geopolymer mixing were sodium hydroxide (NaOH) and sodium silicate (Na 2 SiO 3 ) with three activator/fly ash ratios which was 0.25, 0.35 and 0.45. The results showed that the fineness level based on fall zone as well as the activator to fly ash ratio significantly influenced the compressive strength of the geopolymer mortar. The compressive strength of the F4-P4 specimen of geopolymer mortar with zone-4 fly ash and an activator ratio of 0.45 achieved 28.2 MPa at 28 days.

Sungai Bendung merupakan salah satu anak Sungai Musi yang memiliki topografi yang relatif datar. Apabila terjadi hujan pada Sub DAS Bendung maka terjadi limpasan permukaan (run off) yang akan menyebabkan banjir. Tujuan dari penelitian ini adalah menghitung besarnya debit limpasan permukaan (run off) pada Sub DAS BendungBagian TengahKota Palembang.Penelitian ini bersifat deskritif yang hanya menggunakan data sekunder.Tahapan dalam penelitian ini yaitu tahap studi pustaka, pengumpulan data, analisis curah hujan, dan analisis limpasan permukaan (run off).Metode yang digunakan dalam analisis limpasan permukaan (run off) adalah Metode Rasional.Hasil dari penelitian menunjukan bahwa debit limpasan permukaan (run off) pada Sub DAS Bendung Bagian Tengah Kota Palembang untuk periode ulang 2, 5, 10, 25, 50, dan 100 tahun adalah 1.533 m3/det; 1.965 m3/det; 2.251 m3/det; 2.612 m3/det; 2.881 m3/det; dan 3.147 m3/det.Hasil dari simulasi aplikasi HecRas 4.1.5 adalah pada kala ulang 2 tahun terjadi banjir 0.1 m -0.25 m pada sta 0 m -1120 m, dan pada kala ulang 5 tahun terjadi banjir setinggi 0.1 m –0.45 m pada sta 0 m -1120 m.