Agus Setyo Muntohar
Universitas Muhammadiyah Yogyakarta

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Journal : Semesta Teknika

Kekuatan Geser Campuran Tanah-Kapur-Abu Sekam Padi Dengan Inklusi Kadar Serat Karung Plastik Yang Bervariasi Widianti, Anita; Hartono, Edi; Muntohar, Agus Setyo
Jurnal Semesta Teknika Vol 10, No 1 (2007): MEI 2007
Publisher : Jurnal Semesta Teknika

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Abstract

Stabilisasi tanah secara kimia yaitu dengan penambahan kapur dan abu sekam padi mampu meningkatkan kekuatan gesernya, namun campuran tersebut cenderung berperilaku getas (brittle). Keadaan ini kurang memuaskan bila digunakan sebagai bahan konstruksi yang lebih menginginkan bahan berkekuatan tinggi tetapi berperilaku ductile. Kombinasi dari teknik perbaikan tanah secara kimia dan secara mekanis (yaitu dengan perkuatan serat-serat plastik) diharapkan akan memberikan hasil yang lebih baik. Tujuan dari penelitian ini adalah untuk mengkaji kuat geser tanah yang distabilisasi dengan kapur-abu sekam padi-serat plastik dengan berbagai variasi kadar serat  dan masa perawatan. Dalam penelitian ini digunakan tanah yang dicampur 12% kapur, 24% abu sekam padi dan serat karung plastik sebanyak 0,1%, 0,2%, 0,4%, 0,8%, dan 1,2% dari berat total campuran. Uji yang dilakukan adalah uji geser langsung pada saat benda uji berumur 7 dan 14 hari. Secara umum dengan adanya penambahan serat karung plastik dan masa perawatan, nilai kohesi, sudut gesek dalam, dan kuat geser mengalami peningkatan dibandingkan nilai pada tanah asli dan tanah yang hanya dicampur dengan kapur-abu sekam padi saja. Campuran tanah - kapur-abu sekam padi dan 0,4 % serat untuk masa perawatan 14 hari memberikan peningkatan nilai kuat geser tertinggi, yaitu sebesar 178,63 % dari nilai kuat geser tanah asli (pada σ = 12,59 kN/m2).
A New Formula For Rate Of Swelling Of Expansive Clay Soils Muntohar, Agus Setyo; Hashim, Roslan
Jurnal Semesta Teknika Vol 8, No 2 (2005): NOVEMBER 2005
Publisher : Jurnal Semesta Teknika

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Abstract

The study of engineered expansive soils attracts the attention of researchers since this soil is mixed and increasingly used in many geotechnical and geoenvironmental application. This paper attempts to the study of swelling properties i.e. swell and swelling pressure, rate of swell, and water adsorption during swell. The kaolin-bentonite mix and sand-bentonite mix specimens are statically compacted and tested in conventional oedometer apparatus for swelling determination. The results of the study show that the mechanism of swell follows three distinct stages: intervoid, primary, and secondary swelling. The swell occurs since the soils adsorb water during water uptake. The rate of swell and maximum swelling are successfully determined using hyperbolic equation.
Uses Of Lime -Rice Husk Ash And Plastic Fibers As Mixtures-Material In High-Plasticity Clayey Subgrade: A Preliminary Study Muhammad, Ario; Muntohar, Agus Setyo
Jurnal Semesta Teknika Vol 10, No 2 (2007): NOVEMBER 2007
Publisher : Jurnal Semesta Teknika

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Abstract

Silica produced from rice husk ashes have investigated successfully as a pozzolanic material in soil stabilization. However, rice husk ash cannot be used solely since the materials lack in calcium element. As a result, rice husk ash shall be mixed with other cementitious materials such as lime and cement to have a solid chemical reaction in stabilization process. The main objective of this study focused on bearing capacity of the stabilized clayey subgrade with lime-rice husk ash and fibers. The main laboratory test shall be compaction and CBR tests. The investigation results revealed that the inclusion of lime-rice husk ash-fiber into the soil decreased MDD and OMC. On the other hand, stabilization and reinforcement with lime-rice husk ash and fibers waste improved significantly the CBR values 
Uji Triaksial Unconsolidated-Undrained pada Campuran Tanah Lanau - Kapur - Abu Sekam Padi dan Serat Karung Plastik Widianti, Anita; Hartono, Edi; Muntohar, Agus Setyo
Semesta Teknika Vol 11, No 2 (2008): NOVEMBER 2008
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v11i2.765

Abstract

Geotechnical and mechanical behaviour of soil stabilized with lime-rice husk ash and strengthened by randomly placed plastic fiber depends on the portions of the added materials and curing time. This research investigates the effect of the waste plastic sack fibers portion and the curing time to the stress – strain relationship and to the shear strength parameters of the mixture. In this study the portions of lime and rice husk ash were set as constant to the value of 12% and 24% respectively. The effect of four waste plastic sack fibers portion variation from 0.1% to 0.8% was measured by unconsolidated-undrained triaxial test. The samples were tested at 7, 14 and 21 days after mixing. In general, according to the test result, the inclusion of randomly waste plastic sack fiber and curing time have enhanced the shear strength parameters, the peak stress and the strain before failure.  With 0.2% fiber content, the cohesion and the internal friction angle values of the samples have increased 335% and 409% respectively compared with those of the samples having no added materials.
A New Formula For Rate Of Swelling Of Expansive Clay Soils Muntohar, Agus Setyo; Hashim, Roslan
Semesta Teknika Vol 8, No 2 (2005): NOVEMBER 2005
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v8i2.897

Abstract

The study of engineered expansive soils attracts the attention of researchers since this soil is mixed and increasingly used in many geotechnical and geoenvironmental application. This paper attempts to the study of swelling properties i.e. swell and swelling pressure, rate of swell, and water adsorption during swell. The kaolin-bentonite mix and sand-bentonite mix specimens are statically compacted and tested in conventional oedometer apparatus for swelling determination. The results of the study show that the mechanism of swell follows three distinct stages: intervoid, primary, and secondary swelling. The swell occurs since the soils adsorb water during water uptake. The rate of swell and maximum swelling are successfully determined using hyperbolic equation.