One of the best concrete mixes to reduce environmental impact is using sulfur concrete. The use of sulfur, as a waste material for enterprises, for the production of building materials is efficient due to the disposal of waste and its contribution to environmental protection. Sulfur concrete material has high compressive strength, low hydraulic conductivity, and high resistance to water permeation and is particularly resistant to corrosion in acid and salt environments. Sulfur concrete is more resistant to corrosion. Waterproofing reduces fatigue under repetitive load, develops strength very high start, fast hardens, saves time to manufacture, and holds to an aggressive environment. The aims of this study were 1) To determine the compressive strength of sulfur-bonded concrete with an aggregate ratio, 2) To determine the compressive strength of concrete based on the percentage of sulfur binding material from the combined aggregate weight and specific gravity of the concrete 3) To determine the strength of the sulfur-bonded concrete with a maximum age of 28 days. The research method used is an experimental method based on calculating the density of concrete specimens and the volume of the mould for sulfur concrete specimens. The results showed that 1) the best percentage of mixed material was aggregate fine and coarse 40%: 60%. 2) With use pro percentage sulfur 25%, 27.5%, 30%, 32.5%, 35%, 37.5% and 40% of heavy aggregate combined and weight type concrete 2400 kg/m3. 3) Research results obtained maximum strength sulfur concrete 28 days old of 429.5 kg/cm2 at 32.5% sulfur percentage and the lowest 250.5 kg/cm2 at the percentage of sulfur 25%.

Pengaruh Lumpur dalam campuran beton secara fisis akan mengurangi angka slump, sehingga campuran beton sulit dikerjakan akibatnya kekuatan beton menurun. Sedangkan secara kimiawi kadar Lumpur dalam campuran beton akan mengakibatkan reaksi kimia yang terjadi antara air dan partikel semen terganggu, akibatnya kekuatan beton juga menurun. Pada penelitian ini mencoba untuk mengetahui pengaru Lumpur pada pasir terhadap kekuatan beton. Dari penelitian diperoleh hasil : Pengaruh kenaikan kadar Lumpur dalam pasir secara signifikan berpengaruh terhadap penurunan niliai slump, untuk kadar lumpur dalam pasir mencapai 25% prosentase penurunan nilai slump mencapai 72,7% dari 11 cm menjadi 3 cm, suatu angka yang sangat rendah untuk nilai slump. Untuk kuat tekan beton umur 7 hari kenaikan kadar Lumpur dalam pasir secara signifikan berpengaruh terhadap penurunan kuat tekan, untuk kadar Lumpur dalam pasir 5 % sampai 10% prosentase penurunan kuat tekan beton mencapai 63,08% dan 64,23% suatu penurunan yang sangat besar sekali, apalagi untuk kadar Lumpur mencapai 25% prosentase penurunan kuat tekan betonnya mencapai 71,54%. Untuk kuat tekan beton umur 28 hari kenaikan kadar Lumpur dalam pasir secara signifikan berpengaruh terhadap penurunan kuat tekan, untuk kadar Lumpur dalam pasir 5 % sampai 10% prosentase penurunan kuat tekan beton mencapai 36,13% dan 37,39% suatu penurunan yang sangat besar sekali, apalagi untuk kadar Lumpur mencapai 25% prosentase penurunan kuat tekan betonnya mencapai 58,97%

<p class="Abstract">This paper presents the results of research on the design of geopolymer concrete mixes. The main objective of this research is to develop an efficient and easy design of low-alkaline activator geopolymer concrete mixture, which until now has been the biggest obstacle in the use of geopolymer concrete. The variables reviewed were the amount of alkaline activator was quite low at 4%, room temperature and 60oC ratio of alkaline activator/fly ash (AAS/FA) were 0.35, 0.4, 0.5, 0.6. The test results show the parameters of geopolymer concrete with low alkali activator 4%, sodium silicate/sodium hydroxide ratio 2.5%, sodium hydroxide molarity 14M, type F fly ash and the discovery of the relationship model of compressive strength and the ratio of alkali activator/fly ash with a very high correlation as basic development of geopolymer concrete mix design. The design of the geopolymer concrete mix developed is easy because it is application-based and efficient because it only requires 4% alkaline activator.</p>

Beton merupakan bahan bangunan yang terdiri dari campuran antara semen Portland, air, aggregate halus, aggregate kasar dengan atau tanpa bahan tambah. Agregate merupakan material penyusun beton terbesar oleh karenanya keadaan aggregate sangat berpengaruh besar terhadap kualitas beton. Agregate yang baik untuk campuran beton adalah aggregate yang kuat, keras, besudut, tidak mengandung lumpur, tidak mengandung zat organik dan bergradasi baik, namun kenyataannya sangat sulit untuk memperoleh aggregate yang bergradasi baik, langsung dari alam. Pada penelitian ini mencoba memperbaiki gradasi aggregate dengan menambahkan filler dan melihat pengaruhnya pada kekuatan beton. Dari penelitian diperoleh hasil : Kekuatan tekan beton untuk campuran beton dengan jumlah semen tetap, semakin meningkat dengan bertambahnya pemakaian filler dari 5% sampai 10 % dan mulai mengalami penurunan saat pemakaian filler ditambah menjadi 15%. Peningkatan kekuatan beton yang terbesar diperoleh dari pemakaian filler abu sekam 10% dengan kenaikan kuat tekan beton sebesar 42,7% dari 253,3 kg/cm2  menjadi 361,38 kg/cm2 .

This paper investigates the mechanical properties of the geopolymer concrete using a moderately low alkali activator. The main objective is to ascertain the compressive strength, split tensile strength, elastic modulus, shear strength, flexural strength and bond strength of the said concrete. The experimental program was carried out by reviewing the variables, namely, the amount of alkaline activator which was set at 4%, and the ratio of alkali activator to fly ash (AA/FA) which was varied from 0.35, 0.4, 0.5 to 0.6. Experimental results show that the geopolymer concrete with 4% alkaline activator could still produce concrete compressive strength above 19 MPa for AA/FA ratio of 0.6 and with treatment at room temperature (33℃). On this basis, the authors derived the empirical equations for geopolymer concrete containing low alkaline activator. These equations were compared with the mechanical property model of geopolymer concrete and that of concrete containing Portland cement. The comparison shows that our model has almost the same trend as the other models.