Abdullah Alida

Strength of Concrete Based Cement Using Recycle Ceramic Waste as Aggregate

The main focus of this research is to study the strength of concrete with ceramic waste as coarse aggregate. The sources of ceramic waste are obtained from the industrial in Malaysia. Presently, in ceramics industries the production goes as waste, which is not under going the recycle process yet. The potential of recycled ceramic waste as a substitute for coarse aggregates in concrete has been investigated. The recycle ceramic waste as aggregate was used. Concrete mixes with a 28 days characteristic strength of 20 MPa were prepared using water/cement ratio of 0.4, 0.5 and 0.7. The strength development of the concrete mixes containing recycled ceramic waste aggregates was compared to that of conventional concrete. The result show that the concrete mixes containing recycled ceramic waste aggregates achieve strength levels between 80 to 95 % compared to the conventional concrete. This indicates that the recycled ceramic waste has a potentially to be used as coarse aggregates for concrete.

Microstructure Studies on Different Types of Geopolymer Materials

Geopolymer is a new binding material produced to substitute the ordinary Portland cement (OPC) function as a binder in concrete. As we know, different types of geopolymer will have different properties. In this research, the different types of geopolymer raw materials had been studied in term of microstructure. Different type of materials which is fly ash (class F) and kaolin had been mixed with alkaline solution consist of sodium silicate and sodium hydroxide with suitable geopolymer raw material to alkaline activator and sodium silicate to sodium hydroxide ratios. The geopolymer samples with different types of raw material were then cured at a temperature 70°C for 24 hr and maintained at room temperature until the testing was conducted. After the geopolymers were aged for seven days, the testing was conducted.

Study on Properties and Morphology of Kaolin Based Geopolymer Coating on Clay Substrates

The application of geopolymer as a coating was not widely explored by other researchers and therefore the study of kaolin based geopolymer coating applied on different types of clay substrate (unsintered and sintered) was carried out. The geopolymer coating paste were initially prepared by mixed the kaolin with alkaline activator (NaOH and Na2SiO3) until homogeneous mixture was obtained. After that, the geopolymer paste then applied on the surface of clay substrates and left to cure at 80°C for 24 hours and sintered at 800°C respectively for 2 hours. Flexural, compression test and SEM for morphology analysis are studied. Based on the results obtained, it shows that kaolin based geopolymer coating can contribute in improving the substrate strength, while curing and sintering temperature applied to the geopolymer coating on different substrate can influence the interaction between substrate and geopolymer paste to diffuse according to SEM image proved.

Effect on Strength and Hardness of Clay Ceramic Substrate after Treatment Using Koalin Based Geopolymer Glaze

Geopolymerization is an alternative for ceramic industry by using clay based material such as kaolin or calcined kaolin geopolymer. Geopolymer paste is initially produced by alkaline activation of calcined kaolin with NaOH and Na2SiO3 solution), dried at 80oC for 4 hours, pulverized and sieved to fixed particle size powder. The parameters involved in this processing route (alkali concentration, kaolin or calcined kaolin to activator ratio, alkali activator ratio and heating conditions) are investigated. Geopolymeric powder is added with water to produce slurry to be coated on the surface of clay ceramic. It undergoes heat treatment at high temperature to produce glaze on the surface. Flexural strength and hardness analysis are studied. Result evidences the processing show of incresing strength value between 8-10% after treatment with geopolymer glaze and also the Vickers hardness values of geopolymers improved.

Microstructure Studies on the Effect of the Alkaline Activators of Fly Ash-Based Geopolymer at Elevated Heat Treatment Temperature

Fly ash-based geopolymers are new binding materials produced to replace the ordinary Portland cement (OPC) used in concrete. In this research, the effect of alkaline activators on the compressive strength and the microstructure of low-calcium (Class F) fly ash-based geopolymers were studied. Fly ash and the alkaline activator were mixed with alkaline activator to fly ash ratios of 0.30, 0.35, and 0.40 at a constant ratio of water glass (sodium silicate) to sodium hydroxide (NaOH). The alkaline activator solution was prepared by mixing water glass with a 15 M NaOH solution. The samples were cured at a temperature 70 °C for 24 hr and maintained at room temperature until the testing was conducted. The test results indicated that the compressive strength increased when the ratio of alkaline activator to fly ash was increased at 7 days. The ratio of 0.4 produced the maximum compressive strength, which was 8.61 MPa. This was due to high reaction rate between the fly ash and the alkaline activator solution. Morphology studies, conducted by SEM analysis of the geopolymer samples, indicated that geopolymers synthesized at a ratio of 0.4 also had the most homogeneous and less porous microstructures, which was attributed to the high dissolution of the fly ash particles in the alkaline activator solution. The microstructure appearance of geopolymers treated heat temperature of 400, 600 and 800°C, shows a sintering process takes place for unreacted fly ash microspheres. It was observed as an overall, the visible microcracks formed on the surface of the highest compressive strength geopolymers only, was due to loss of water during heating.

Mechanical Properties of ZTA Composite Using Cold Isostatic Pressing and Uniaxial Pressing

Alumina-zirconia composite is an engineering material with a great potential to be develop for application as high temperature resistance structural material. In this research, zirconia toughness alumina (ZTA) was produced by physical interaction between Al2O3 powder and Y2O3-ZrO2 powder. Two composition of powder with different Al2O3: Y2O3-ZrO2 ratio was used, 70:30 and 80:20 by weight. Two different compaction methods, i.e. uniaxial pressing and cold isostatic pressing (CIP) with a maximum load of 150 MPa were used in this research to investigate the differences in properties of composites. Sintering process was done at four different temperatures with the heating rate is 5 o C/ min with a soaking time of five hours. Mechanical testing, i.e. compressive strength and hardness was performed to all samples. The microstructure analysis using a Scanning Electron Microscope SEM was also studied. From the result, the composite with the ratio of 70:30 showed better mechanical properties as compared to 80:20 composite. Addition of zirconia in the composite gave an increased in toughness due to transformation toughening mechanism of tetragonal to monoclinic phase. As a conclusion the composites produced high compaction green density will improved the sintering process, resulting in improved mechanical properties.