Muhammad Faheem Mohd Tahir

Effect of Microwave Curing to the Compressive Strength of Fly Ash Based Geopolymer Mortar

With the advancement of technology and the economic crisis in Malaysia, has been promoting the development of infrastructure in the use of new structural materials but overall is unsatisfactory in terms of cost savings. One of the alternatives that can be used is to use fly ash as a cement replacement in manufacturing mortar. Replacement of cement with geopolymerization mortar can reduce manufacturing costs and could reduce global warming arising from the production of cement for the production of Portland cement for the release of CO2 into the atmosphere, where CO2 gas gives the largest contribution to global warming . The study will be focused on the effect of microwave curing with various durations and temperature to the mechanical and physical properties of fly ash based geopolymer mortar. For the conventional heating technique, heat is distributed in the specimen from the exterior to the interior leading to the non-uniform and long heating period to attain the required temperature. Application of microwave to the fresh concrete results in removal of water, collapse of capillary pore and densification of sample. Heat curing has been applied to construction materials especially for the precast concrete to improve the strength development process. This concrete attains sufficient strength in short curing time, so the molds can be reused, and the final products can be rapidly delivered to the site. The effect of curing temperature together with their aging days of the cured product will also be investigated. Mechanical properties of the product will be tested using compressive test, and density of the samples.

Strength and Density of Geopolymer Mortar Cured at Ambient Temperature for Use as Repair Material

Geopolymers produced by synthesizing aluminosilicate source materials with an alkaline activator solution promised an excellent properties akin to the existing construction material. This study focused on the effect of various binder to sand ratio on geopolymer mortar properties. Mix design of geopolymer mortar was produced using NaOH concentration of 12 molars, ratio of fly ash/alkaline activator and ratio Na2SiO3/NaOH of 2.0 and 2.5 respectively. Samples subsequently ware cured at ambient temperature. The properties of geopolymer mortar were analysed in term of compressive strength and density at different period which are on the 3rd and 7th day of curing. Experimental results revealed that the addition of sand slightly increase the compressive strength of geopolymer. The optimum compressive strength obtained was up to 31.39 MPa on the 7th day. The density of geopolymer mortar was in the range between 2.0 g/cm3 to 2.23 g/cm3. Based on this findings, the special properties promoted by geopolymer mortar display high potential to be implemented in the field of concrete patch repair.

Potential of Geopolymer Mortar as Concrete Repairing Materials

Geopolymer mortars which produced by the reaction of fly ash with an alkaline activator and added with sand is going to be developed for use as concrete repair material. Thus, the typical and standard requirement as repair material is reviewed. This paper also discusses the efficiency of geopolymer mortar which is mainly dependent on the excellent bond between the sand and geopolymer binder. Based on the determined formulation of geopolymer mortar, the standard for testing is determined making it potentially becoming as an excellent repair materials.

Flood Mud as Geopolymer Precursor Materials: Effect of Curing Regime on Compressive Strength

This paper studies the effect of curing temperature and curing duration to the flood mud based geopolymer on compressive strength properties. Flood mud was used as a raw material for geopolymer and geopolymer samples were synthesized by using sodium silicate and sodium hydroxide 14M solution. These samples were cured at different temperature (100°C, 150°C, 200°C and 250°) for different curing duration (6h, 12h and 24h) respectively. Compressive strength tests were carried out at after 28 days. The compressive strength and SEM analysis of geopolymer products were evaluated. Result showed that the maximum compressive strength was 24 MPa at temperature of 150°C for 24 hours. With increasing ageing day, densification of geopolymer gel was observed.

The Effect of NaOH Concentration and Curing Condition to the Strength and Shrinkage Performance of Recycled Geopolymer Concrete

Concrete is widely used as a material construction. Globally, the consumption of concrete was estimated to be more than 8 billion tons per year. Nowadays, many problems arise related to concrete manufacturing occur especially on environmental issues. A key concern for environmentalists has always been climate change. One of the ways to mitigate the impact activities on the climate is to reduce carbon footprint. Portland cement are commonly been used in concrete is responsible for about 5% of all CO2 emission. It is reported by Davidovit that the production of one ton of Portland cement emits approximately one ton of CO2 into the atmosphere. There are several ways to reduce environmental pollution that cause by production and utilization of Portland cement, one of it is Geopolymer concrete. Subsequently Geopolymer concrete incorporating with recycle concrete aggregate (RCA) is one of the alternative to further reduce carbon footprint and as well as can reduce waste. Geopolymer concrete is a concrete that use no cement and produced by the combination of alkaline activator and supplementary cementitious material (SCM) such as fly ash, boiler ash, waste paper sludge ash (WPSA), ground granulated blast-furnace slag (GGBS), and so on in order to reduce carbon emission. In this study the Waste Paper Sludge Ash (WPSA) were used as a SCM and the combination of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as a binder. Two (2) series of geopolymer concrete specimens comprising two (2) different molar of sodium hydroxide (NaOH) which are 8M and 14M were adopted. The effect variable alkaline molarity on the compressive strength and shrinkage of the geopolymer concrete specimens is tested at the age of 3, 7, 14 and 28 days. The mixture of geopolymer concete with 8M of sodium hydroxide (NaOH) concentration then was categorized into three (3) groups. Each group were been cured at different curing condition which are in ambient condition, oven, and external condition. The size of specimens prepared were 100mm x 100mm x100mm. The result shows that the molarities of sodium hydroxide (NaOH) influenced the strength of Waste Paper Sludge Ash (WPSA) based geopolymer concrete produced incorporating with increasing of recycle concrete aggregate (RCA). The result also show that the geopolymer concrete undergoes very low shrinkage. Curing condition will also effect the strength of geopolymer concrete produced.

Fly Ash Based Lightweight Geopolymer Concrete Using Foaming Agent Technology

This paper presents the mechanical properties of a lightweight geopolymer concrete synthesized by the alkali-activation of a fly ash source (FA) produced by mixing a paste of geopolymer with foam produced by using NCT Foam Generator. Two curing conditions are used, curing at room temperature and curing in an oven with a constant temperature which is 60 oC. Bulk density showed that fly ash-based geopolymer lightweight concrete is light with the density of 1225 kg/m3 - 1667 kg/m3 with an acceptable compressive strength of 17.60 MPa for the density of 1667 kg/m3.

Performance and Characterization of Geopolymer Concrete Reinforced with Short Steel Fiber

In the recent years, geopolymer concrete are reporting as the greener construction technology compared to conventional concrete that made up of ordinary Portland cement. Geopolymer concrete is an innovative construction material that utilized fly ash as one of waste material in coal combustion industry as a replacement for ordinary Portland cement in concrete. The uses of fly ash could reduce the carbon dioxide emission to the atmosphere, redundant of fly ash waste and costs compared to ordinary Portland cement concrete. However, the plain geopolymer concrete suffers from numerous drawbacks such as brittleness and low durability. Thus, in this study the addition of steel fiber is introduced in plain geopolymer concrete to improve its mechanical properties especially in compressive and flexural strength. Characterization of raw materials also determined by using chemical composition analysis. Short type of steel fiber is added to the mix in weight percent of 1 wt%, 3 wt%, 5 wt% and 7 wt% with fixed molarity of sodium hydroxide of 12M and solid to liquid ratio as 2.0. The addition of steel fiber showed the excellent improvement in the mechanical properties of geopolymer concrete that are determined by various methods available in the literature and compared with each other.

Mechanical properties of geopolymer lightweight brick with styrofoam pellet

The utilization of fly ash in brick as partial replacement of cement is gaining immense importance today, mainly on account of the improvement in the long-term durability of brick combined with ecological benefits. In this research, the lightweight brick was produced by using fly ash (class F) as a main material to replace Ordinary Portland Cement (OPC) in the composition of brick. Class F Fly Ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and styrofoam pellet was added to the geopolymer mixture to produce lightweight brick. The brick was prepared in two methods that is wet method and dry method due to different brick composition which is dry method for composition with sand and wet method for composition without sand. The bricks were cured in room temperature at 7 aging days. After 7 days, the compressive strength, water absorption, and density of the brick were investigated, where the optimum ratio for the best bricks has been determined from the lightweight d...

Compressive and bonding strength of fly ash based geopolymer mortar

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 t...

Effect of different sintering temperature on fly ash based geopolymer artificial aggregate

This research was conducted to study the mechanical and morphology of fly ash based geopolymer as artificial aggregate at different sintering temperature. The raw material that are used is fly ash, sodium hydroxide, sodium silicate, geopolymer artificial aggregate, Ordinary Portland Cement (OPC), coarse aggregate and fine aggregate. The research starts with the preparation of geopolymer artificial aggregate. Then, geopolymer artificial aggregate will be sintered at six difference temperature that is 400°C, 500°C, 600°C, 700°C, 800°C and 900°C to known at which temperature the geopolymer artificial aggregate will become a lightweight aggregate. In order to characterize the geopolymer artificial aggregate the X-ray Diffraction (XRD) and X-Ray Fluorescence (XRF) was done. The testing and analyses involve for the artificial aggregate is aggregate impact test, specific gravity test and Scanning Electron Microscopy (SEM). After that the process will proceed to produce concrete with two type of different aggrega...