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All Journal Rekayasa Sipil Semesta Teknika
As’at Pujianto, As’at
Universitas Muhammadiyah Yogyakarta
Civil Engineering, Building, Construction & Architecture Engineering

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Pengaruh Penggunaan Bambu Sebagai Pengganti Agregat Split terhadap Kuat Tekan Beton Ringan Pujianto, As’at; Tajuddin, M.
Jurnal Semesta Teknika Vol 15, No 2 (2012): NOVEMBER 2012
Publisher : Jurnal Semesta Teknika

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Abstract

The use of bamboo as an aggregate replacement is one of the efforts to reduce the density and static load of structural elements, sincethe structural strength of bamboo is high. This study focus on the issue of the using bamboo as aggregate concrete with flowing method on a review of specific gravity and compressive strength of the concrete. This study uses bamboo as a percentage of the aggregate at 0% (normal), 20%, 40%, 60%, 80% and 100% of the conventional split and using additional silicafume aggregates. Specimens used in this study is the concrete cylinder (diameter 15 cm and height 30 cm). The identification and testing of tap density after 14 days of treatment.Results show that using more bamboo aggregate will result lower slump value, higher water absorption, decreasing in both specific gravity and compressive strength.
Beton Mutu Tinggi dengan Bahan Tambah Superplastisizer dan Fly Ash Pujianto, As’at
Jurnal Semesta Teknika Vol 13, No 2 (2010): NOVEMBER 2010
Publisher : Jurnal Semesta Teknika

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Increasing concrete strength is one of the main necessities of concrete technology. For more than the last 20 years, high strength concretes with compressive strength ranging from 50 MPa up to 140 MPa have been used worldwide in high rise buildings and bridges with long spans, or buildings in aggressive environments. But in Indonesia high strength concretes possesses maximum compressive strength of 60 MPa. The properties of concrete are affected by cementitious matrix, aggregate, and the transition zone between these two phases. Reducing the water-cement ratio and the addition of pozzolanic admixtures like fly-ash are often used to modify the microstructure of the matrix and to optimise the transition zone. The reduction of the water-cement ratio results in a decrease in porosity and refinement of capillary pores in matrix, but flowing ability of the concrete will also decrease so that it can’t be workable. Then it workablity can be improve by the use of a superplastisizer. The method used refers to the planning of normal concrete, which is contained in the SKSNI 03-2834-1992. The results showed that superplastisizer with doses of more than 2% of the cement paste does not increase the strength of concrete. For all the rest of the experiments, the superplastisizer dosage was determined about 2 % of the powder mass. The first tests showed a good workability of the fresh concrete and a good self compacting ability with the fly-ash dosage of 12 % of the powder mass. The interest in reducing costs for increasing the concrete strength, can be successfully achieved in this research.
Pengaruh Lapisan Pasir di Bawah Fondasi terhadap Redaman dan Frekuensi Natural Akibat Beban Gempa Pujianto, As’at
Jurnal Semesta Teknika Vol 12, No 1 (2009): MEI 2009
Publisher : Jurnal Semesta Teknika

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Sand layer under foundation has been widely used for vibration damping by an earthquake since centuries ago. Due to being located in earthquake-zone and sand as natural material is widely distributed over regions, research on the use of sand for earthquake vibration damping is becoming important in Indonesia. The aim of this work is to study sand layer behavior in reducing earthquake vibration. Parameters of soil structure, i.e. damping ratio, displacement, soil pressure, and the change of natural frequencydue to the existence of sand layer under foundation were observed. In this study, soil structure was modeled as layered soil profile where top layer is a clay soil layer. Foundation base is located at a depth of 300 cm underlying varied thicknesses of course sand layer, i.e. 0, 50, 100, 150 and 200 cm under foundation. In order to produce various soil pressures, load magnitudes of 0, 10,000, 20,000, 30,000 and 40,000 tons were selected. Therefore, earthquake loadings with high and low frequency from Koyna and Bucharest earthquake record were implemented to soil structure models. Results showed that the increase of sand layer thickness does not essentially affect to the decrease of displacement. It is depending on the frequency of an earthquake. However, a thickness of 50 cm shows decrease of displacement due to high and low frequency earthwuake loading with the average deviation of 3.67 %. The displacement due to Bucharest earthquake loading is greater than that of Koyna earthquake, with the average ratio of 9.38 times. If ground frequency is higher than earthquake frequency, ground displacement is becoming smaller.
Beton Mutu Tinggi dengan Admixture Superplastisizer dan Aditif Silicafume Pujianto, As’at
Jurnal Semesta Teknika Vol 14, No 2 (2011): NOVEMBER 2011
Publisher : Jurnal Semesta Teknika

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Abstract

Increasing concrete strength is one of the main necessities of concrete technology. For more than the last 20 years, high strength concretes with compressive strength ranging from 50 MPa up to 140 MPa have been used worldwide in high rise buildings and bridges with long spans, or buildings in aggressive environments. But in Indonesia high strength concretes possesses maximum compressive strength of 60 MPa. The properties of concrete are affected by cementitious matrix, aggregate, and the transition zone between these two phases. Reducing the water-cement ratio and the addition of pozzolanic admixtures like fly-ash are often used to modify the microstructure of the matrix and to optimise the transition zone. The reduction of the water-cement ratio results in a decrease in porosity and refinement of capillary pores in matrix, but flowing ability of the concrete will also decrease so that it can’t be workable. Then it workablity can be improve by the use of a superplastisizer. The method used refers to the planning of normal concrete, which is contained in the SK-SNI 03-2834-1992. The results showed that superplastisizer with doses of more than 2% of the cement paste does not increase the flowing ability of the paste anymore. For all the rest of the experiments, the superplastisizer dosage was determined about 2 % of the powder mass. The first tests showed a good workability of the fresh concrete and a good self compacting ability with the silicafume dosage of 10 % of the powder mass. The interest in reducing costs for increasing the concrete strength, can be successfully achieved in this research.
Analisis Kuat Tekan Beton Mutu Tinggi Dengan Bahan Tambah Superplastisizer Dan Limbah Las Karbit Prayuda, Hakas; Pujianto, As’at
Rekayasa Sipil Vol 12, No 1 (2018)
Publisher : Department of Civil Engineering, Faculty of Engineering, University of Brawijaya

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Abstract

This research will discuss about the compressive strength of concrete by using superplastisizer as an addictive substance and waste of carbide weld as the admixture material of cement replacement. Through this research is expected to know the right composition to produce a concrete formula with high quality by utilizing the existing local waste dan superplastisizer (Viscocrete-10). In this study made a sample of concrete cylinders measuring 15 cm diameter with a height of 30 cm totaling 63 specimens with 7 variations with each variation made as many as 9 specimens. The compressive strength test was performed at age 7, 14 and 28 days. Through this research, the result of flowability, compressive strength and elastic modulus of each test object variation.
Co-Authors Hakas Prayuda M. Tajuddin, M.