Key Engineering Materials Vol. 673

Abstract: Self-healing cement is a novel topic in concrete technology. Concrete is created to have its own ability to heal cracks. Crack closure is due to the material deposition of the gap so causing the crack closed. Materials used in this paper is mortar composition with ordinary portland cement replaced by calcium carbonate (CaCO₃) and rice husk ash. There are three testing presented in this paper. The first is compressive test to determine the compression applied to mortar for initial cracks. The second is an ultrasonic pulse velocity (UPV) test to observe the depth of cracks and density of each composition. The third is macroscopic investigation to observe cracks wide in each mixture. The maximum compressive strength of 22.46 MPa shown by specimens made with 10% rice husk ash and 10% calcium carbonate cement. By the end of healing process, it reached 23.18 MPa. It was also shown that in crack depth decreased from 38 mm to 16 mm. From this analysis, it can be concluded that rice husk ash (RHA) and calcium carbonate (CaCO₃) can be utilized as self-healing concrete materials.

Abstract: In this study, the ability of treated oil palm ash aided with kaolin powder to produce zeolites is studied. The palm ash has been treated with citric acid via a leaching process to get rid of the metallic impurities in it. The usage of treated oil palm ash in the zeolites conversion seems to be an option for waste materials management. Characterization of treated oil palm ash from Malaysia’s palm oil plantation has been cleared. The treated oil palm ash and kaolin powder are used as the starting material for the synthesis of zeolites materials. The method chose for the zeolites conversion is alkaline hydrothermal treatment. The chemical composition, crystalline phases and elemental composition of treated oil palm ash and as-synthesized samples were characterized and studied. From the analysis, the treated oil palm ash was a fertile source of silica and exists as quartz phase. The outcomes have significant motivation for the production of zeolites by using low cost material such as treated oil palm ash.

Abstract: Geopolymer or alkali-activated binder is produced by synthesizing aluminosilicate source materials with an alkaline activator solution. This study has been conducted to produce palm oil boiler ash (POBA) geopolymer brick/IBS brick by using geopolymerisation method. Mix design of geopolymer brick/IBS brick was produced using NaOH concentration, ratio of S/L, ratio Na₂SiO₃/NaOH and curing temperature of 14 M, 1.5, 2.5 and 80 °C. The ratio of POBA-to-sand for geopolymer brick/IBS brick for this study was 1:3. The properties of geopolymer brick/IBS brick were analyzed in term of compressive strength, water absorption and density at different aging period, which is 1st, 3rd, 7th, 28th and 60^th days. The result showed that the geopolymer brick produced using POBA, showed an increment in strength with times where the maximum strength obtained was up to 16.1 MPa (60^th days). The density of this brick was in the range 1615 kg/m³ to 1750 kg/m³ and can be classified into medium weight for non-loading brick according to ASTM C129 (2013). As for the water absorption, the range was 6.8% to 12.2%, which is less than limit (17%) of ASTM C90 (2013) specification. For geopolymer IBS brick, the maximum compressive strength at 60th days was 14.3 MPa. There are slightly different strength of geopolymer IBS brick, which is due to the existence of tongue and groove on the surface of IBS brick thus leads to lower strength. The geopolymer IBS brick was classified as medium weight brick according to ASTM C129 (2013) with density a in the range 1792 kg/m³ to 1894 kg/m³ and water absorption 8.7% to 14.5%.

Abstract: The non-availability of natural lightweight aggregate and demand are increasing in worldwide, thus new alternatives on producing artificial aggregate should be developed. This paper discussed on the mechanical properties of artificial lightweight geopolymer aggregate (ALGA) made from LUSI mud and alkaline activator in concrete. LUSI means Sidoarjo mud from Indonesia which erupted on 2006 with high volume and impacted an area of almost 770 hectare. The alkaline activator used was combination of sodium hydroxide and sodium silicate. The geopolymer paste formed need to be pelleted and sintered at 950 °C. The results showed that the compressive strength of OPC-ALGA concrete is 41.89 MPa at 28 days of testing with a density of 1760.1 kg/m³ which can be classified as lightweight concrete. The water absorption of ALGA concrete is 2.77%.

Abstract: Glass powder is known as a reactive material with silica content more than 72% and potentially considered as pozzolanic material. Moreover, it is known that binder containing silica fume 10-26% by weight increases the compressive strength of concrete. A low water to binder ratio is needed to increase the strength. In this paper, materials for making paste were analyzed for X-Ray Fluorescence (XRF), X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), and reactivity. Composition of paste with the highest strength at 28 days was 93.26 MPa. Glass powders had higher reactivity compared to silica fume. Therefore, the recommended amount of glass powder to increase mechanical properties is 10 – 15% from cement weight and silica fume content are 40 – 60% from glass powder weight. A tendency of strength increasing after 28 days was found. In general, addition of silica fume to glass powder prolonged the initial setting causing the distance between initial and final setting time became closer.

Abstract: Kaolin, widely used aluminosilicate source material was added with alkaline activator solution, creating geopolymer coating paste.Optimum design for kaolin based coating using geopolymer technology was studied. The work was to analyses the effect of solid liquid ratio, sodium silicate and sodium chloride ratio and sodium chloride molarity on its adhesive performances on lumber wood substrate. Upon observation, coating with 0.9 solid/liquid ratio, 0.45 sodium silicate/sodium chloride ratio and sodium chloride solution with 6M molarity shows promising adhesive strength. These results were further evident with morphological studies.

Abstract: The effects of mixing approach on compressive, flexural, water absorption properties and morphology of the epoxy nanocomposites incorporating 0 and 3 wt% fly ash-based geopolymer were investigated. The mechanical stirrer with two different type of propeller; four blade (type A) and dissolver (type B) was used to blend the epoxy with the nanoclay and the fly ash-based geopolymer filler. It was found that the epoxy nanocomposite prepared using dissolver propeller (type B) performed higher compressive strength and higher flexural strength as compared to the one prepared using four blade propeller (type A). We postulate that this was due to an improved mixing efficiency and dispersion quality as observed through Field Emission Scanning Electron Microscopy (FESEM).

Abstract: Oil palm clinker is made from waste burning of oil palm shell and the fibrous material in oil palm mill. The clinker has changed into permanent state, which is no longer a bio-material after undergone high temperature burning process. Large quantities of various sizes of oil palm clinker wastes have become disposal constraints. It requires extra costs for handling, transporting and searching out the suitable dumping sites. Study was found that the clinker is lightweight and satisfactorily achieved compressive strength to make lightweight concrete structure. Several lightweight oil palm clinker concrete beams were designed and tested according to British standard Code of Practices. The results shows the provision can be conservatively used to design the lightweight oil palm clinker concrete beam reinforced with deformed bar. Experimental loads were found higher than the design loads for all the tested beams. Therefore, the equation used to calculate ultimate load is safe and satisfactory.

Abstract: Profiled steel sheeting dry board (PSSDB) system is made of profiled steel sheeting that is connected to the dry board using a self-drilling, self-tapping screw. This study aims to predicts the load-deflection behavior of PSSDB panel system under the influence of geopolymer concrete infill with finite element modeling. To achieve the target objective, the laboratory testing approach and a theoretical system behavior prediction are considered. Through a bending test, the stiffness of PSSDB full board with geopolymer concrete infill (FBGPC) panel is 27.42 kNm² and the ultimate load is 13.13 kN/m². The developed finite-element modeling (FEM) successfully predicts the behavior of PSSDB with geopolymer concrete infill panel with >85% accuracy.