Showing papers by "Januarti Jaya Ekaputri published in 2014"
TL;DR: In this paper, the authors describe one of the varying factors influencing the mechanical properties of geopolymer concrete and concretes made with 8M NaOH and activators ratio of 2 have the highest compressive strength.
Abstract: This paper describes one of the varying factors influencing the mechanical properties of geopolymer concrete. Fly ash and volcanic material called trass was used as raw materials, while sodium Hydroxide (NaOH) and Sodium silicate (Na2SiO3) was applied as an alkali activator. Mechanical properties were assessed by compressive test, the concentration of NaOH used in this study was eight and ten Molars, and ratio of Na2SiO3 to NaOH by mass was 0.5, 1, 1.5, 2, and 2.5. Test results indicated that the strength of geopolymer concrete and binder were hardly influenced by concentration of NaOH in solution and the activator ratio. Binder with activator ratio of 2.5 has the highest compressive strength both in 8M and 10M NaOH system. However, in concrete, there are a few difference, concretes made with 8M NaOH and activators ratio of 2 have the highest compressive strength. This result might due to the low workability of fresh geopolymer concrete. On the other hand, binder and concrete made with 10M NaOH, showed the highest compressive strength when they were made with the activator ratio of 2,5.
31 citations
TL;DR: In this article, the authors used the solid form of Sidoarjo mud as a base material of lightweight-geopolymer paste, which was mixed with a class F fly ash.
Abstract: This paper presents the efforts of how to use the solid form of Sidoarjo mud as a base material of lightweight-geopolymer paste. The mud, which is called Lusi was mixed with a class F fly ash. Some experimental results have shown that mixing mud with fly ash and alkali was potential to become a binder in concrete, instead of Portland cement. Alkaline solutions used in the mixture were NaOH of 12 M and 14 M and Na2SiO3 combined in the ratio of 1:2.5 by weight. Aluminum powder was applied as a foaming agent. It showed that the strength of paste made with mixing Sidoarjo mud and fly ash was influenced by mud content. The effect of chemical admixture and curing temperature was observed as well. A steam curing method at 60°C was applied to the paste for three and six hours. Test results showed that the compressive strength of the paste varied with the concentration of alkaline solution, mud content, admixture and curing temperature. The maximum strength of the lightweight paste at 21 days was 2.8 MPa with the density of 722 kg/m3.
19 citations
TL;DR: In this paper, the effect of microwave-incinerated Rice Husk Ash (MIRHA) on the mechanical properties of fly ash geopolymer concrete was investigated. And the results showed that the performance of MIRHA-fly ash concrete improved with the use of oven curing as the curing regime for the concrete samples.
Abstract: This paper provides a report about the results of an investigation carried out to understand the effect of Microwave Incinerated Rice Husk Ash (MIRHA) on the mechanical properties of fly ash geopolymer concrete to access the concrete performance development. Fly ash (350kg/m3) and MIRHA (0%, 3%, and 7%) were used as the source materials to replace cement, NaOH and Na2SiO3 solutions used as the alkaline liquids for the medium of polymeric reaction. In addition, sugar was used as retarder, as well as three different types of curing regime (ambient, external exposure or oven curing regime). The concrete mixing procedure was adjusted to obtain the proper homogeneity of dry materials and wet ones. In this project, a number of mechanical tests have been conducted including the pull-out test, compressive strength test, flexural strength test, and modulus of elasticity test. It was then observed that the performance of mechanical properties of MIRHA-fly ash geopolymer concrete improved with the use of oven curing as the curing regime for the concrete samples.
15 citations
TL;DR: In this article, a mixture of calcined-Sidoarjo mud, fly ash and alkaline activator was used as a pozzolanic material to create geopolymer paste.
Abstract: Sidoarjo mud has been a disaster for society and government of Indonesia, but this material contains of SiO2, Al2O3 and Fe2O3 so that significantly to be expected as a potential pozzolanic material. It would be very useful to take the advantages of the material. Moreover, lightweight concrete is widely applied especially at high-rise buildings in order to reduce the risk of earthquake. In general lightweight concrete is made with less Portland Cement associated with lime and pozzolanic materials as a binder. In this paper, calcined-Sidoarjo mud was introduced as pozzolanic material to create geopolymer paste. Geopolymer binders were made with a mixture of calcined-Sidoarjo mud, fly ash and alkaline activator. The specimens were then mixed with a commercial chemical foamed agent to get lightweight geopolymer binders. The results showed that the mixing with the ratio of fly ash : NaOH: Na2SiO3 were 33,3% : 33,3% : 9,52 % : 23,81% and superplasticizer was 2,5% of binder weight achieved the compressive strength of 55,6 MPa. With additional 1% of foaming agent, the compressive strength of lightweight geopolymer binder was 7.1 MPa
4 citations