The current study is related to laboratory investigations to utilize Central Kalimantan coal ash as a sustainable construction material, which is green paving blocks. For this purpose, coal ash from the Pulang Pisau coal-fired power plant, both in the form of fly ash and bottom ash, was used as an additional proportion of cement. The addition of fly ash was set at 10%, 20%, and 30%. Meanwhile, the addition of bottom ash was set at 5%. Water to binder ratio (w/b) was set at 0.45, and the curing times were set at 7, 28, and 56 days for all samples. Moreover, the sample’s compressive strength test was based on BS 6717:1986 regarding the precast concrete paving block. Based on the test results, it was proven that the addition of fly ash and bottom ash could increase the compressive strength of paving blocks. The highest compressive test results were obtained from the addition of 20% fly ash and 5% bottom ash (24.62) MPa at the age of 56 days. This result is 30% higher compared to the ordinary paving blocks test result. Furthermore, according to SNI 03-0691-1996, paving blocks with a compressive strength of 20 MPa until 40 MPa can be applied as parking lots pavements.

In this study, effects of crushed stone waste from Katunun’s quarry as fine aggregate on mortar and concrete properties will be examined. Samples with varying crushed stone waste replacement ratio, ranging between 0% until 100%, will be analysed at 3, 7 and 28 days curing time. Mortar sample is using 0.5 w/c ratio, while concrete sample is using 0.45 w/c ratio. The mixture of mortar sample is based on SNI 03-6825-2002, whilst concrete sample is based on SNI 03-2834-2000. The examination of concrete samples workability was conducted based on the slump test according to SNI 1972:2008. Moreover, the compressive strength test of mortar sample is based on SNI 03-6825-2002. In addition, the compressive strength test of concrete sample is based on SNI 1974:2011. Regarding compressive strength of mortar samples, the average compressive strength results of mortar with crushed stone waste rose significantly in line with the increase in replacement ratio. As for the workability of fresh concrete, sample using natural river sand had better workability compared to sample using crushed stone waste. However, the workability of concrete with crushed stone waste is still meet the slump value specified in the job mix formula. In addition, it has been found out that the combination of 75% crushed stone waste with 25% river sand will give the highest compressive strength compared to others combinations. Based on these findings, the utilization of crushed stone waste from Katunun’s quarry in mortar and concrete mixture can be proposed.

Penelitian ini bertujuan untuk mengetahui kuat tekan beton dengan variabel agregat dan air dari beberapa lokasi kuari di Kabupaten Tanah Laut dan Kabupaten Banjar Kalimantan Selatan. Pada penelitian ini telah dilakukan pemeriksaan bahan campuran beton (baik kerikil, pasir dan air yang digunakan), pembuatan rencana campuran beton, serta hasil uji tekan sampel beton dan rekomendasi yang dapat diberikan. Pada penelitian ini menggunakan acuan pembuatan campuran beton (Job Mix) sesuai dengan Peraturan Menteri Pekerjaan Umum No. 11/PRT/M/2013 tentang Pedoman Analisis Harga Satuan Pekerjaan Bidang Pekerjaan Umum. Untuk kerikil yang diuji yaitu batu batu split Katunun, batu split gunung Martadah dan batu split gunung Awang Bangkal. Adapun air yang diuji adalah air dari sungai maluka dan awang bangkal. Adapun air PDAM juga digunakan pada sampel kontrol. Adapun faktor air semen ditetapkan sebesar 0.5 terkecuali campuran beton dengan agregat Awang Bangkal dan air PDAM yang menggunakan faktor air semen 0.4, 0.45 dan 0.5. Dari penelitian ini diketahui bahwa agregat batu gunung Martadah memberikan nilai kuat tekan yang lebih konsisten. Adapun untuk struktur beton dengan kekuatan sedang, penggunaan agregat Awang Bangkal sangat direkomendasikan. Sedangkan ketiga jenis air yang diujikan pada penelitian ini dapat digunakan dalam campuran beton.  Kata kunci: agregat lokal, campuran beton, kuat tekan beton

A deep beam is a beam with a small ratio of its shear span to its effective depth. Deep beams at failure under shear mechanism behave as brittle in contrast to the normal beams which become ductile under the flexural mechanism. The shear failure of deeps beams can be prevented by providing a sufficient amount of web shear reinforcements. Providing horizontal web reinforcement to the RC deep beams is a way to increase their capacity to shear. Testing of the studied deep beams was performed by Finite Element Method (FEM) modeling with the aid of ANSYS software. To obtain valid parameters for modeling RC deep beams in FEM modeling, calibrating test have to be done through verification and validation processes. The study results of all studied RC deep beams show that by closing up the spacing between the horizontal web reinforcement results in increment in the ultimate load, while the ultimate deflection and the curvature ductility were found to be decreasing. For RC deep beams, the placing configuration of horizontal web reinforcement at 0.5h-0.7h was found to be efficient for gaining higher values of ultimate deflection and curvature ductility compared to the placing configuration at 0.3h-0.5h with similar values of ultimate load. It was also found that all the specimens’ crack patterns at the first crack state were caused by flexural-tension while at the ultimate state, they were caused by the shear mechanism.

This study compares two methods in enhancing fly ash as a soft-soil stabilizer. The first is using fly ash with mixing proportion varies from 10%, 15%, and 20%. In the second method, 10% cement combines with fly ash mixing proportion in the first method. Based on CBR test results, the fly-ash effectively increases the soft soil capacity with a CBR maximum of 9.31% at 20% fly ash in the first method. The second method enhances more impact than the first method with a CBR maximum of 49.36% at 20% fly ash. The swelling value keeps decreasing with the increase of fly ash content, and adding cement to fly ash-soft soil mixture can further minimize the swelling value by two times compared to only fly ash as the stabilizing agent.