#TITLE_ALTERNATIVE#

• Main Author: (NIM: 35012003), ROSIDAWANI
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/30692
• Institution: Institut Teknologi Bandung

<p align="justify">The development of high strength concrete demands an improvement over the natural behavior of brittle concrete into ductile. Concrete strength and ductility are considered in that development of concrete materials. Synthetic fiber reinforced concrete is one of the innovation to improve the brittle nature of concrete. Many studies showed that the performance fiber reinforced concrete has deformation resistance especially in post crack conditions. Synthetic fiber reinforced concrete (SNFRC) is able to increase the capacity of tensile, flexural and tension stresses, as well as to show good residual strength and energy adsorption strength. The compression ductile behavior of SNFRC allows its application to column elements. <br /> <br /> <br /> Since the brittle behavior of high strength concrete column increases, it requires the tighter confinement as well as the complicated configuration of the reinforcement detailing to achieve ductile behavior. However, the tighter confining reinforcement will cause problems. The tight confining reinforcement causes the difference in stress between the cover and the core concrete so that there will be "plane of weakness" between them. This will lead to premature spalling, lowering the strength capacity before the confining stress works. In addition, the tighter and more complicated configuration of the reinforcement detailing creates difficulties at the site. The difficulties faced by the handyman and the lack of strict supervision in carrying out the reinforcement detailing work cause the reinforcement work is not as expected. As the result, those will affect to the overall behavior of the columns. <br /> <br /> <br /> This dissertation aimed to answer the problem by developing concrete material with the use of modified olefin macro-type synthetic fiber (SNFRC) to improve the mechanical characteristics of concrete, in the form of ductile behavior. The ductile behavioral ability of column is expected to provide a constraint mechanism along with reinforcement bars to produce a better-performing column elements. <br /> <br /> <br /> The study consisted of 3 stages, i.e. mechanical testing of SNFRC material and 2 types of column element structure testing. The mechanical testing of SNFRC consisted of some cylinders of compression and tensile stress and modulus elasticity as well as some beams of modulus of rupture and flexure behavior. The structure element speciment tests consisted of 20 columns with concentric axial load and 4 columns with axial-lateral cyclic load. The main test variables for both types of tests were the synthetic fiber volume ratio and the space of confining reinforcement (volumetric ratios). The reference specimen made of non-fiber concrete with minimum volumetric ratios based on SNI 03-2847-2013. The column specimen of the concentric axial test have diameter of 135 mm diameter and height of 600 mm height with the same longitudinal reinforcement configuration (6 D8mm). The columns were confined by 6 mm diameter of spiral with consisting of spacing of 60 mm, 45 mm and 30 mm with each consisting of 1.25%, 0.75% and 0% fiber additions (non-fiber concrete). The specimens with spacing of 30 mm and 0% fiber addition was become the reference. While in cyclic axial-lateral tests with axial ratio of 0.3 Po, the column specimens have cross section area of 260 mm x 260 mm and height of 1500 mm with the same longitudinal reinforcement configuration (8 D13 mm). The columns were confined by 10 mm diameter of ties with consisting of spacing of 90 mm, 60 mm and 45 mm with each consisting of 1.25%, 0.75% and 0% fiber additions (non-fiber concrete). The specimens with spacing of 45 mm and 0% fiber addition was become the reference. <br /> <br /> <br /> The result of the material mechanical tests showed a more ductile of synthetic fiber reinforced concrete. The application of synthetic fiber reinforced concrete to the concentrically axial column elements as well as cyclic axial-lateral load can increase the ductile behavior of the columns. The specimen columns which used synthetic fiber reinforced concrete by reducing column volumetric ratios up to 50% tended to behave identically with the reference columns. Thus it can be concluded that the combination of confining reinforcement and a number of volume fraction of the synthetic fibers contributed to the reinforcing mechanism of the core concrete, thereby increasing the strength and a significantly increasing the ductile behavior of the columns. <br /> <br /> <br /> The results of this study also indicated that the use of synthetic fiber reinforced concrete in the column can reduce the use of the minimum volumetric ratios required under the article 23.4.4 of SNI 03-2847-2013. The study also proposed the SNFRC stress-strain model, the confined SNFRC stress-strain model, and those both models are able to produce SNFRC moment-curvature model. The stress strain models were made as the formula constructed from the function of the effective confinement indefinite index due to the combined contribution of the confining reinforcement and a number of volume fraction of synthetic fibers. <br /> <br /> The development of high strength synthetic fiber reinforced concrete has been proven to increase the ductile behavior of columns and enables the reduction of volumetric ratios of confining reinforcement. This renewal innovation of the research that has been achieved is expected to contribute to the science, especially in civil engineering.<p align="justify"> <br />