Search

This research aims to study the morphological properties of fly ash based geopolymer paste as a repair material when applied on ordinary Portland cement (OPC) concrete substrate. The first part of this study investigates the optimal mix design of FA-based geopolymer paste with various NaOH concentrations of 8, 10, 12, and 14 molar in term of morphological analysis, which were used later as a repair material. The second part studies the morphology between the geopolymer repair material and OPC substrate concrete. The results showed that 12M revealed the best where there are no voids, cracks or unreacter fly ash occur on the sample. The results also shows that 12M sample highly irregular with no visible plane fracture surfaces revealed good bonding between geopolymer material and conrete substrate.

The waste from construction and demolition works are of large volume and increasing in time. This study was implemented to determine the effect of superplasticizer on the mechanical properties of concrete containing Recycled fine Cement Brick Aggregate (RFCBA). Recycled Fine Cement Brick Aggregate (RFCBA) was produced by crushing such waste cement brick and the particles size of crushed RFCBA was identified. The concrete mixture was formulated by using replacement method where the RFCBA was replaced by percent to the concrete, 0%, 25%, 50%, 75% and 100% without and with 1% superplasticizer with the water cement ratio of 0.5. Two tests were conducted to identify the mechanical properties of concrete names as compressive strength and density. The test results found that the strength properties indicate a good result where 75% replacement of RFCBA with 1% superplasticizer recorded to have the highest strength, higher than control concrete.

In recent years, research and development of geopolymers has gained significant interest in the fields of repairs and restoration. This paper investigates the application of a geopolymer as a repair material by implementation of high-calcium fly ash (FA) as a main precursor, activated by a sodium hydroxide and sodium silicate solution. Three methods of concrete substrate surface preparation were cast and patched: as-cast against ordinary Portland cement concrete (OPCC), with drilled holes, wire-brushed, and left as-cast against the OPCC grade 30. This study indicated that FA-based geopolymer repair materials (GRMs) possessed very high bonding strength at early stages and that the behavior was not affected significantly by high surface treatment roughness. In addition, the investigations using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy have revealed that the geopolymer repair material became chemically bonded to the OPC concrete substrate, due to the formation of a C&ndash, A&ndash, S&ndash, H gel. Fundamentally, the geopolymer network is composed of tetrahedral anions (SiO4)4&minus, and (AlO4)5&minus, sharing the oxygen, which requires positive ions such as Na+, K+, Li+, Ca2+, Na+, Ba2+, NH4+, and H3O+. The availability of calcium hydroxide (Ca(OH)2) at the surface of the OPCC substrate, which was rich in calcium ions (Ca2+), reacted with the geopolymer, this compensated the electron vacancies of the framework cavities at the bonding zone between the GRM and the OPCC substrate.

Filtration is the process where the solid particles are separated from the solution by passing it through porous pores. This process always comes together with the adsorption method and it depends on the type of filter media being used. Currently, activated carbon, zeolite and sand are widely used in treating wastewater influent. However, the increasing demands and materials cost had encouraged various approaches in finding solutions to replace the current filter media. Therefore, eggshell waste is introduced in this study as a replacement material for zeolite to treat wastewater impurities. The usage of eggshell waste as a new filter media is more beneficial which represents a low cost, renewable, available and sustainable approaches. Thus, this study revealed the optimum proportion of Eggshell Powder (ESP) as a filter media for wastewater treatment. The amount of eggshell used varies from 20%, 40%, 60% and 80% labelled as S3a, S3b, S3c and S3d respectively. The parameters examined were BOD, COD, SS, turbidity, colour, NH3-N, NO3-N, Fe and pH. This study had found that the most efficient filter media to replace zeolite is S80 media. S3d media was able to remove almost all the examined parameters with high percentage removal range between 40% to 90% removal. As a conclusion, this study hopes that by utilizing an industrial waste as a low-cost adsorbent, the environmental ecosystem can be protected for the sake of next generations.

This study was carried out to overcome major problem in flexible asphalt pavement and conventional rigid pavement that used Ordinary Portland Cement (OPC). Because of expensive maintenance cost of flexible pavement, rigid pavement is a solution for the dilemma. However, based on previous research found that Ordinary Portland Cement emitted large amount of greenhouse gases known as carbon dioxide that effect environmental surrounding. So fly ash based geopolymer is proposed to solve the problem because the energy consumption (than lead to emission of carbon dioxide) is less compare to ordinary Portland cement. Fly ash based geopolymer is obtained by mixed of fly ash and alkaline activator. The alkaline solution is divide into molarity of sodium hydroxide which 12M and different ratio of sodium silicate to sodium hydroxide 1.5, 2.0, 2.5, 3.0. Next different sample solid to liquid with ratio of 1.5, 2.0, 2.5, and 3.0. All of the sample then cure at room temperature. Then, the sample morphology will be analyse using Scanning Electron Microscopy while the chemical composition is analyse by X-Ray Fluorescence. Then mechanical properties test by Unconfined Compressive Strength. It noted that from this study, the higher strength and properties can be obtained and implement into application of rigid pavement.

Fly ash as the name signifies is made from fly ash generated from the thermal power stations along with lime and gypsum. Pulverized fuel ash is called fly ash and is mostly generated from thermal power stations where it is generated by burning of coal. Almost 25-30% less cement or motor the fly ash bricks must require. Immense strength and bonding these bricks are made from machines easily arranged in symmetrical structures providing, hence, they are uniform in shape and size. These bricks absorb significantly less water the outside cement wall plastering is not required in case of fly ash bricks as they are grey and have smooth and uniform texture. These are much lighter in weight as compared to conventionally used red bricks thereby reducing the transportation and dead building costs. Moreover, such as fly ash bricks do not require firing which is an important manufacturing step for the red bricks and therefore does not contribute to environmental pollution.

Geopolymer is an attractive construction binder owing to its ability to improve the properties of the concrete and preserves the environment from the high CO2 emission. Geopolymer technology will convert the potential hazardous industrial waste such as fly ash into valuable construction materials. However, there is a need of studying the properties of iron-based geopolymer in order to enhance the fundamental and knowledge of the geopolymer research also development in this study area. Fly ash which contains a significant amount of iron oxide (Fe2O3) was used as a precursor and tested at different curing duration (1, 3, 7, 14 and 28 days). Crystallization of iron oxide (Fe2O3) contained in the fly ash under geopolymerization process will be able to turn waste fly ash into a strong concrete materials, simultaneously creating a waste-to-wealth economy. Furthermore, the formation of fayalite detected from the microstructure characterization is mainly contribute to the strength development of the fly ash after 28 days curing.

Dolomite is a carbonate mineral in nature. Dolomite (CaMg(CO3)2) is an anhydrous carbonate mineral composed of calcium, magnesium, and carbonate. The word dolomite is also used to describe the sedimentary carbonate rock, which is composed predominantly of the mineral dolomite (also known as dolostone). Dolomite had been one of the frequent used materials in most of researches due to its accessibility to acquire and the properties. The composition of Ca and Mg became one of the main attractions for the usage of this natural mineral. One of the main properties needed to be studied when using any materials is morphology of the martial. Morphology analysis can give much valuable information about the surface topography and composition of the sample. Other than that, detailed three-dimensional and topographical imaging can also be obtained. This can helps the researches to finds the core value or the novelty in their study. Thus, reviews for the morphology analysis of dolomite were done to investigate how the structures of dolomite develop for certain study and usage. Besides that, dolomite as an addition into certain materials were reviewed and compared to observe the interactions and changes happened.

Ceramic materials have demonstrated impressive performance under severe conditions in a wide number of areas including health, energy and environment, transportation and electronic applications. In order to meet the growing demand of specific properties of ceramics, the use of geopolymer method were introduced as an alternate way by providing new material to fabricate geopolymer as ceramic precursor and moving towards green technology. Geopolymer ceramic was produced using fly ash as source materials. Different molarities of sodium hydroxide solution in the range of 8 M to 14 M were used in the preparation of fly ash geopolymer ceramic. The ratio of fly ash/alkaline solution and alkaline activator were kept constant at 2.0 and 2.5 respectively. Physical and mechanical properties such as density, flexural strength and shrinkage were determined. The optimum flexural strength of 61.6 MPa is obtained at the sodium hydroxide concentration of 12 M with the density of 2.21 g/cm3. The formation of almost fully crystalline phase with appearance of albite contribute to the flexural strength of fly ash geopolymer ceramic. Microstructure image result shows that a presence of pores due to sintering effect and smoother matrix which gives denser structure as supported by the excellent density.

Geopolymer which is produced by synthesizing aluminosilicate source materials with an alkaline activator solution promotes sustainable and excellent properties of binder. The purpose of this paper is to determine the optimum binder to sand ratio of geopolymer mortars based on mechanical properties. In order to optimize the formulation of geopolymer mortar, various binder to sand ratios (0.25, 0.33, 0.5, 1.0, 2.0, 3.0, and 4.0) are prepared. The investigation on the effect of sand inclusion to the compressive and bonding strength of geopolymer mortar is approached. The experimental results show that the bonding strength performance of geopolymer is also depends on the various binder to sand ratio, where the optimum ratio 0.5 gives a highest strength of 12.73 MPa followed by 12.35 MPa, which corresponds the ratio 1.0 for geopolymer, while the compared value of OPC bonding strength is given by 9.3 MPa. The morphological structure at the interface zone is determined by Scanning Electron Microscope (SEM) and the homogenous bonding between geopolymer and substrate can be observed. Fly ash based geopolymers reveal a new category of mortar which has high potential to be used in the field of concrete repair and rehabilitation.

Geopolymerization consists of several chemical reactions that has been reported widely as an exothermic reaction. Previous studies on heat released during geopolymerization used metakaolin and fly ash of F class as a precursor for geopolymer. Meanwhile, in this study, fly ash of C class is used and a preliminary study has been conducted on determining the exothermic reaction of the geopolymerization with various ratios of solid-to-liquid ranging from 1.5 to 2.5. The amount of heat released was determined by using Differential Scanning Calorimeter. It was proven that different solid-to-liquid ratio affected the amount of heat released during geopolymerization as the highest amount of the heat released were recorded at the optimum solid-to-liquid ratio of 2.0.