Concrete is considered one of the construction materials that contribute the most significant carbon dioxide in the world. Meanwhile, according to various studies, concrete production will continue to rise through 2050, especially in developing countries. According to several reports, cement manufacture is one of the largest sources of carbon dioxide in the concrete sector. In addition, overexploitation of aggregates due to concrete production also causes unavoidable natural damage. Bottom ash waste was used as a replacement for cement and fine aggregate as sustainable construction materials. It is envisaged that this research would allow industrial waste to be utilized to its full potential, resulting in a concrete that is more environmentally friendly and minimizes carbon dioxide emissions during the manufacturing process. This study is divided into bottom ash as a cement substitute and bottom ash as a fine aggregate substitute. The engineering properties of the concrete were checked during the experiments in this study when it was fresh and hardened states. The slump test is used to determine the workability of fresh concrete. While for the hardened properties tests consist of compressive strength, splitting tensile strength, flexural strength, and mass density. The usage of bottom ash as a cement replacement demonstrates that as the composition of bottom ash increases, the performance of the hardened properties of concrete decreases. While using bottom ash as a fine aggregate replacement reveals that the performance of hardened properties has improved as the proportion of bottom ash utilized has increased. Doi: 10.28991/CEJ-2022-08-01-014 Full Text: PDF

This study employs rice husk ash and pozzolan cement as additional soil stabilization materials. This study aims to evaluate the bearing capacity of the soil to be used as embankment soil for subgrade pavement materials. The soil samples were collected from two different areas in the Yogyakarta region, Indonesia, namely the Wates and Imogiri regions. This study consists of experimental approach that defines a soil embankment for road subgrade with a trapezoid-shaped with top dimension of 10 cm x 20 cm, a base dimension of (20 cm x 40 cm), and a height of 10 cm. In addition, the specimens in this study were divided into two groups: the embankment with a 1 cm-thick sand base and the embankment without a sand base. The USCS classified the samples from Wates as OH-type or organic clays with moderate to high plasticity and by AASTHO as group of A-7-5 (22). The soil from Imogiri was categorized as inorganic silt or fine diatoms sand with OH clumps or AASTHO classified this soil as group A-7-5 (11). The addition of rice husk ash and pozzolan cement as stabilizing soil materials has a moderate effect on the engineering properties of the soil, particularly the bearing capacity and bearing capacity ratio of soil. This soil stabilization also demonstrates that the engineering properties of the stabilized soil significantly improved compared to the original soil without stabilization.

Excessive use of cement makes the price of construction projects expensive. Mortar making using high amounts of cement also has the potential to increase the price of the construction. This study discusses the use of agricultural waste as a substitute for cement in mortar production. The waste used in this study was bagasse ash, fuel ash palm oil, and rice husk ash. Each waste is added as much as 25%, 50% and 75% which are then tested for mechanical properties such as water content, unit weight, absorption, and IRS. Compressive strength was tested when the mortar was 28 days old with a cube-shaped specimen with a size of 50 mm x 50 mm x 50 mm. From the test results, it was found that all of this waste can be used as a substitute for cement. To produce a compressive strength of 100 kg/cm2 can add each waste with a percentage range of 10-12% of the weight of cement.

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.

Analisis Kuat Tekan Beton Mutu Tinggi Dengan Bahan Tambah Superplastisizer Dan Limbah Las Karbit