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Abstrak :
The internal erosion is a common mode of failure in earth dams. The phenomenon of filtration process corresponds to a transport over long distances of fine particles under the effect of seepage forces. The filters arranged by both sides of the clay core are supposed to be dimensioned so to stop this transfer. In a granular material, the constriction is very important in the filtration process. It is the narrowest path linking pores. If there is a fluid flow and the constriction size is larger than the diameter of particle, the particle follows its route. On the other hand, if the constriction size is smaller than the diameter of particle, the particle is stopped. Then, the curve of cumulative size constrictions for a granular material is identified as the key characteristic of the filtration process. This characteristic depends on the density and size distribution curve of the filter. The objective of this research is to find and compare the curve with three different approaches by using periodic conditions. These three approaches are MEDTD (Discrete Element Method Triangulation Delaunay), the probabilistic approach and the inverse approach by experiment.

Abstrak :
Beton merupakan material getas dan lemah terhadap tarik dibandingkan baja. Salah satu solusi untuk mengatasi kelemahan beton adalah penambahan serat plastic jenis polypropylene dalam bentuk kemasan air minum pada material beton. Berangkat dari keberhasilan fiber reinforced concrete, maka dilakukan penelitian mengenai pengaruh penambahan cacahan limbah gelas plastik PP dalam meningkatkan kinerja beton. Tujuan penelitian ini adalah untuk mempelajari efektifitas penggunaan cacahan limbah plastik PP terhadap peningkatan kuat tekan dan kuat geser beton dengan fc? = 25 MPa, di samping itu untuk mengurangi penumpukan limbah gelas plastik minuman yang terus meningkat setiap tahun.

Kadar cacahan polypropylene yang ditambahkan pada beton normal adalah 0,00 kg/m3 (0,00 %); 0,90 kg/m3 (0,10 %); 1,80 kg/m3 (0,20 %); 2,70 kg/m3 (0,30 %); 4,50 kg/m3 (0,50 %); 6,30 kg/m3 (0,70 %); 9,0 kg/m3 (1,00 %); 18,0 kg/m3 (2,00 %); 27,0 kg/m3 (3,00 %) untuk pengujian kuat tekan dengan umur benda uji 7 hari dan 28 hari, serta 0,00 kg/m3 (0,00 %); 0,90 kg/m3 (0,10 %); 1,80 kg/m3 (0,20 %); 2,70 kg/m3 (0,30 %); 4,50 kg/m3 (0,50 %); 6,30 kg/m3 (0,70 %); 9,0 kg/m3 (1,00 %) untuk pengujian kuat geser dengan umur benda uji 28 hari.

Percobaan pembebanan yang dilakukan meliputi pembebanan untuk uji tekan beton, uji geser beton dan uji modulus elastisitas beton. Benda uji percobaan uji tekan dan uji modulus elastisitas beton adalah silinder dengan diameter 15 cm dan tinggi 30 cm. Benda uji percobaan uji geser beton adalah balok double ? L dengan ukuran ( 5 , 7 30 20 × × ) cm⊃³;.

Penelitian dilaksanakan di Laboratorium Struktur dan Material Departemen Sipil Fakultas Teknik, Universitas Indonesia. Metode yang digunakan dalam penelitian ini adalah metode eksperimental. Hasil pengujian akan dibahas dengan analisa kuantitatif, analisa kualitatif dan analisa biaya. Metode pengujian untuk material dasar dan beton mengacu pada ASTM Standard, sedangkan untuk metode rancang campur beton berdasarkan U.S. Bureau of Reclamation.

Dari hasil penelitian beton, dapat disimpulkan dengan bertambahnya kadar cacahan, cenderung adanya penurunan slump pada penambahan kadar cacahan lebih besar dari 0,30%. Dari hasil pengujian, pada penambahan kadar cacahan polypropylene 1,00% terjadi peningkatan kuat tekan 7 hari sebesar 5,000%. Sedangkan tidak ada peningkatan kuat tekan yang signifikan pada kuat tekan 28 hari. Pada penambahan kadar 0,50% peningkatan kuat geser 28 hari sebesar 42,647%.

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Concrete as construction material is known brittle material and has weak tensile strength, compared to steel material. Therefore, need an alternative solution to improve characteristics of the concrete. One of the alternative solution is by adding fiber polypropylene plastic waste on normal concrete.

Based on the successful of fiber reinforced concrete, this research is done by adding crushed polypropylene plastic waste to improve characteristics of the concrete material. The object of this research is to learn the effect of usage polypropylene plastic waste in compressive and shear strength with fc? = 25 MPa, besides to decrease urban waste problem.

The proportion of crushed polypropylene added to normal concrete are 0,00 kg/m3 (0,00 %); 0,90 kg/m3 (0,10 %); 1,80 kg/m3 (0,20 %); 2,70 kg/m3 (0,30 %); 4,50 kg/m3 (0,50 %); 6,30 kg/m3 (0,70 %); 9,0 kg/m3 (1,00 %); 18,0 kg/m3 (2,00 %); 27,0 kg/m3 (3,00 %) for compressive strength test on 7 days and 28 days, also 0,00 kg/m3 (0,00 %); 0,90 kg/m3 (0,10 %); 1,80 kg/m3 (0,20 %); 2,70 kg/m3 (0,30 %); 4,50 kg/m3 (0,50 %); 6,30 kg/m3 (0,70 %); 9,0 kg/m3 (1,00 %) for shear strength test on 28 days.

The tests consist of compressive test, shear test and modulus of elasticity test. The specimen for compressive and modulus of elasticity test is cylinder with 15 cm diameter and 30 cm height. The specimen for shear test is double ? L beam with sizing ( 5 , 7 30 20 × × ) cm³.

The research is done at Structure and Material Laboratory Civil Engineering Department, University of Indonesia. This research used experimental method. The result of experiment will analyze by quantitative analysis, qualitative analysis and cost analysis. Standard test method for raw material and concrete is based on ASTM Standard. Mix design method is based on U.S. Bureau of Reclamation. The result for slump test remain stable by adding crushed polypropylene plastic waste until 0,30%. After proportion of crushed polypropylene is higher than 0,30% added on normal concrete, slump value will decrease.

From the compressive test on 7 days, there is 5,00% of compressive strength improvement by adding 1,00% of crushed polypropylene plastic waste on normal concrete. From the compressive test on 28 days, there is no significant result of compressive strength improvement. From the shear test on 28 days, there is 42,65% of shear strength improvement by adding 0,50% of crushed polypropylene plastic waste on normal concrete

Abstrak :
This paper presents a set of numerical simulations of different 2D boundary-value problems in order to validate a “smoothed-particle hydrodynamics”-“arbitrary Lagrangian-Eulerian” (SPH-ALE) code. This code is intended to be used to study, among other things, the problem of piping erosion in dams and dikes. The case of viscous fluid flows around a fixed cylinder was first examined. Different Reynolds numbers and different shapes for the cylinder were considered. The drag coefficient, lift coefficient, pressure coefficient, and Strouhal number were compared with previous studies from the literature. Next, a validation of the case of a Poiseuille flow between smooth pipe walls with Re = 100 was provided. The friction coefficient was computed and compared to existing analytical solutions.