Light Weight Geopolymer Paste Made with Sidoarjo Mud (Lusi)

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 Na2SiO3combined 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.

Chemical and Physical Characterization of Fly Ash as Geopolymer Material

“…The pH value was tested by dissolving fly ash into distilled water followed with pH measurement. Fly ash with pH value ranged from 8 to 11 tends to experience rapid setting [14]. In addition, pH value of fly ash has closely correlation with its CaO content.…”

“…[13] The research conducted by Tajunnisa stated that more irregular shape particles required more water in mixing geopolymer paste [8].With the purpose of produce geopolymer paste, water content is represented by alkali solution. It is also concluded that concentration and composition of alkali solution plays an important role in developing mechanical properties of geopolymer paste [20][21][22].…”

“…On the other hand, SEM is required to analyze the shape, surface and internal structure of fly ash particle [6,12]. Previous research explained that chemical composition, morphology and crystalline mineral component of fly ash influenced mechanical and physical properties of its geopolymer paste such as compressive strength and setting time [13][14][15].…”

The effect of steam curing on chloride penetration in geopolymer concrete

“…Past studies have confirmed that steam curing at a temperature range of 60 o C-80 o C contributes to faster strength development at early age [9] and promotes the reaction of geopolymerization [10,11]. On the other hand, some studies have suggested that moist curing is more recommended than wet curing [12].…”

The Effect of High Temperature on Compression Strength of Geopolymer Paste

“…Examples of geopolymer concrete raw materials derived from coal combustion waste (fly ash). Utilization of industrial waste material and non industry are the other reason why geopolymer concrete worth the continued research [3][4][5][6][7][8][9][10] to support environmental researches.…”