Nickel slag is one kind of nickel ore smelting waste after the combustion process. Production of nickel slag PT. Antam Pomalaa Kolaka Southeast Sulawesi province during the period 2011-2012 period approximately 1 million tons of slag / year, with a nickel content in ore processing of nickel is between 1.80% to 2.00%. Visually, the physical form of this nickel slag aggregate resembles. Research on the use of nickel slag as an aggregate in concrete mixture is carried out using a cylindrical specimen with a diameter of 15 cm and 30 cm high by 48 pieces were tested at 28 days with some variations in the mix. Variation 01, 100% natural aggregate, variation 02, nickel slag as coarse aggregate, variation 03, nickel slag as fine aggregate, and variation 04, nickel slag as coarse aggregate and fine aggregate. Aggregate gradation in the mixture is set and is designed so that it meets the specifications gradation mix for maximum aggregate size of 40 mm. The composition of the concrete mixture used is a mixture of concrete with the ratio of cement : fine aggegate : coarse aggregate is 1: 2: 3 in a weight ratio with cement water ratio (fas) is set at 0.5. The results showed that when compared with the use of natural agregate, terak nickel is used only as a coarse agregate, a fine agregate only and combined agregate coarse and fine agregates resulting slump values ??fell 39.47%, an increase of 55.26%, and an increase of 34.21%. As a coarse agregate, terak nickel increases the compressive strength, modulus of elasticity and splitting tensile strenght, respectively for 42.27%, 19.37% and 23.46%. As fine agregate, nickel terak resulting value of compressive strength, modulus of elasticity and tensile strength divided down respectively by 16.75%, 6.70% and 24.58%. As a combination of coarse and fine agregate, terak nickel increases the compressive strength, modulus of elasticity and splitting tensile strenght, respectively for 10.31%, 9.26% and 6.70%.
The influence of calcium chloride (CaCl2) as an accelerator for the compressive strength development of concrete made with type I Portland pozzolan cement (PPC) as a hydraulic binder has been investigated. Natural sand and crushed stone were used as fine aggregate and coarse aggregate, respectively. The mix proportion of concrete, by weight, was 1.0 binder: 2.1 fine aggregate: 3.4 coarse aggregate and the water-binder ratio was 0.57. The calcium chloride added to the concrete mixture was 0%, 1.0%, 1.5%, and 2.0% by binder weight. The compressive strength test was performed at 1, 3, 7, 28, and 90 days. The test results show that adding CaCl2 to a concrete mixture accelerates the development of compressive strength. The compressive strength gain was about 36–48% at 1 day and about 29–33% at 3 days, compared to control concrete. Moreover, it increases the compressive strength of PPC concrete about 3–16% at 28 days and about 7–19% at 90 days. The optimum dose of CaCl2 to accelerate the development of compressive strength at the early age and to produce the highest compressive strength in the long-term was about 1.5%.
Semen merupakan bahan utama membuat beton, yang menghasilkan gas CO2 pada proses produksinya yang dapat mencemari lingkungan. Kebutuhan semen yang meningkat setiap tahunnya membuat semen lebih banyak diproduksi, sehingga perlu dilakukan inovasi membuat beton salah satunya beton geopolimer. Penelitian membuat beton geopolimer dengan bahan dasar abu terbang dan aktivator NaOH dan Na2SiO3. Gradasi butiran pasir dan koral dirancang, pada zona 2 dan gradasi koral dengan butiran maksimum 20 mm. persentase agregat dengan abu terbang dan aktivator sebesar 75%:25%. Perbandingan pasir dan koral digunakan 1:1,24. Dibuat 3 campuran C1,C2, dan C3 dengan persentase abu terbang dan aktivator sebesar C1, 70%:30%, C2 65%:35%, dan C3 60%:40%. Perbandingan Na2SiO3 dan NaOH sebesar 1:1.5 dengan molaritas NaOH 14 M. Beton dicetak kubus 15 cm x 15 cm, kemudian dipanaskan pada suhu 700C selama 24 jam. Pengujian kuat tekan beton dilakukan pada umur 7, 14, dan 28 hari masing masing menggunakan 3 benda uji. Penelitian bertujuan untuk mendapatkan campuran yang terbaik dan menghasilkan kuat tekan beton yang tertinggi. Hasil menyatakan bahwa pengurangan jumlah abu terbang dan penambahan aktivator meningkatkan nilai slump beton geopolimer, serta menurunkan kuat tekan beton geopolimer. Beton geopolimer mengalami peningkatan kuat tekan hingga 14 hari, hal ini terjadi pada beton C1, C2, dan C3. Pada umur 14 hari hingga 28 hari kuat tekan beton geopolimer tidak mengalami perkembagan, bahkan cenderung mengalami penurunan terutama pada beton C3. Campuran beton geopolimer yang terbaik terdapat pada beton C2, dengan kuat tekan sebesar 48,89 MPa pada umur 28 hari.
The provision of clean water is still a very serious problem in some places. Many times, water is available in abundant quantities but the quality does not meet human needs. On the other hand, there is a lot of locally available raw materials available for producing ceramic filters which in turn can be used to produce clean water from polluted water. The wild and domesticated fern grows widely in Southeast Asia. The stem can be used as the carbon material for producing filters. This study aims to utilize the fern stem as indigenous material to produce an affordable, easy to use, robust clay base water filter for the less advantaged communities. Chopped fern stem mixed with clay in several compositions (50%, 60%, 70%, 80%, 90% clay), shaped to produce 2 cm thick biscuits with 10 cm diameter, and dried for one week at room temperature and then fired at 9000C overnight. It was found that biscuits with 50% and 60% clay can be used as filters and filter with 50% clay produced filtrate with a better quality which meets the Indonesian standards for class two water which is water for drinking but not potable water. Therefore the fernstem is a potential raw material for ceramic filter production.
The implementation of government procurement of goods and service is governed by presidential regulation number 70 year of 2012. According to that, in Badung Regency implemented centralized in Procurement Service Unit of Badung Regency. As the one of Indonesia procurement unit pilot, Procurement Service Unit of Badung Regency has given the opportunity to perform a self assessment of its maturity levels as government unit. The objective of this research is to find factors that influence Procuremet Service Unit of Badung Regency maturity levels, and also to find out in what level is Procurement Service Unit of Badung Regency stand. Data collection for this research have done by using questionnaire that involve 50 respondents who understand very well about the duties and function of Procurement Service Unit of Badung Regency to perform a government procurement of good and services. The data analysis have been performed by use of factor analysis and supported by SPSS program. The result shows there are 3 factors that influent the Procurement Service Unit of Badung Regency maturity levels, which are : the synergy and organization culture, resources and risk management and organization’s performance development. Whereas the maturity levels of Procurement Service Unit of Badung Regency is stand at compliance. Based to the factors that formed, the highly commitment and strong leadership of Badung Regency leader are very decisive to push ahead the enhancement and the development of Procurement Service Unit of Badung Regency. First thing can be done is to establish an independent Procurement Service Unit therewith its Procurement Unit Development road maps that can be tiered and sustainable plan, monitor and evaluate
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.