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Pujianto, As'at
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Kuat Tekan Beton dan Nilai Penyerapan dengan Variasi Perawatan Perendaman Air Laut dan Air Sungai Pujianto, As'at; Prayuda, Hakas; Zega, Berkat Cipta; Afriandini, Besty
Semesta Teknika Vol 22, No 2 (2019): NOVEMBER 2019
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.222243

Abstract

Penelitian ini membahas pengaruh dari perawatan beton menggunakan air laut dan air sungai terhadap karakteristik beton. Tujuan dari penelitian ini untuk menjelaskan pengaruh dari jenis air pada perawatan beton, khususnya pada beton yang digunakan yang berhubungan langsung dengan air. Pada penelitian ini menggunakan tiga jenis produk semen yaitu Holcim, Tiga Roda dan Gresik dengan total 12 variasi dan 108 benda uji berbentuk silinder berdiameter 15 cm dan tinggi 30 cm. Seluruh variasi menggunakan standar mix design yang sama dengan 6 variasi menggunakan perbedaan jumlah superplasticizer dan 6 variasi menggunakan bahan tambah fly ash. Pengujian yang dilakukan berupa pemeriksaan workabilitas, kuat tekan dan nilai penyerapan. Hasil pada pengujian ini menunjukkan bahwa nilai workabilitas pada beton menggunakan superplasticizer lebih baik dibandingkan beton menggunakan bahan tambah fly ash. Hasil kuat tekan menunjukkan bahwa seluruh benda uji dengan perawatan air laut lebih tinggi dibandingkan dengan beton menggunakan perawatan air sungai. Sedangkan nilai penyerapan menunjukkan bahwa pada umur 28 hari dengan menggunakan air laut menghasilkan nilai yang lebih tinggi dibandingkan perawatan menggunakan air sungai. This study will discuss the effect of concrete treatment using sea water and river water on the characteristics of concrete. The purpose of this study was to determine the effect of water types in concrete treatment, especially for concrete used directly in contact with water. In this study three types of cement brands, Holcim, Tiga Roda and Gresik were used with a total variation of this study as many as 12 with the number of test specimens of 108 cylindrical concrete measuring 15cm in diameter and 30 cm in height. All variations use the same mix design and then modified with 6 variations using super-plasticizer added material while the remaining 6 variations use material added admixture in the form of fly ash which then carried out workability testing, compressive strength and percentage of absorption. The results of this study indicate that the level of concrete workability using superplasticizer added material is much better than using materials added by fly ash. The results of the compressive strength obtained showed that almost all specimens with soaking seawater had a higher compressive strength than concrete with treatment with river water. Absorption results show that at 28 days the seawater absorption rate is greater than river water.  
Evaluasi Beton Bertulang terhadap Perlakuan Panas (Tinjauan pada Tegangan Tarik dan Modulus Elastis Tulangan Baja Lateral) Riswanto, Riswanto; Pujianto, As'at; Zulfiar, Muhammad Heri
Semesta Teknika Vol 16, No 2 (2013): NOVEMBER 2013
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/st.v16i2.4908

Abstract

Fires phenomena have made demands to a building planner to protect, evaluate, and predict the performance of a building after a fires process. The main attention was given to the type of material, in this case, the reinforced concrete that used as a structural element, which due to heating and cooling cycles are alternating, and then the elements of reinforced concrete structures undergo a phase change both in the physical and chemical. This research related to the evaluation of reinforced concrete quality with a focus on heat treatment and reviews tensile stress and elastic modulus of the steel reinforcement. Specimens used in this study was a model of the reinforced concrete beam with a concrete cover types K250 and K300, 7.5 mm of rebar diameter and 2 cm of concrete cover thickness. Heat testing performed after 28 days of treatment with closed combustion in the furnace (heat chamber) without loading at a temperature of 1000ºC for 10 hours, holding time for 1 hour, and slows cooling for 10 hours. In normal specimens, the tensile test results show an equivalent stress value of 324.12 MPa. In specimens heat treatment with a concrete cover of K250, the tensile stress value was 259.52 MPa, while in the K300 was 263.76 MPa. Optimum tensile stress value in normal specimens was 568.62 MPa, and in specimens with heat treatment and with the K250 concrete cover was 473.74 MPa and amounted to 494.41 MPa for K300. The value of tensile fracture stress in normal specimens amounted to 552.52 MPa, and in specimens with heat treatment and with the K250 concrete cover amounted to 461.52 MPa and amounted to 465.24 MPa for K300. Elastic modulus values for normal specimen was 1,612,963.61 kg/cm2, while in specimen heat treatment with the K250 concrete cover was 1,287,888.05 kg/cm2 and was 1,311,545.42 kg/cm2 for K300.