Impact of Blending on Strength Distribution of Ambient Cured Metakaolin and Palm Oil Fuel Ash Based Geopolymer Mortar

This paper investigates the influence of blending of metakaolin with silica rich palm oil fuel ash (POFA) on the strength distribution of geopolymer mortar. The broadness of strength distribution of quasi-brittle to brittle materials depends strongly on the existence of flaws such as voids, microcracks, and impurities in the material. Blending of materials containing alumina and silica with the objective of improving the performance of geopolymer makes comprehensive characterization necessary. The Weibull distribution is used to study the strength distribution and the reliability of geopolymer mortar specimens prepared from 100% metakaolin, 50% and 70% palm and cured under ambient condition. Mortar prisms and cubes were used to test the materials in flexure and compression, respectively, at 28 days and the results were analyzed using Weibull distribution. In flexure, Weibull modulus increased with POFA replacement, indicating reduced broadness of strength distribution from an increased homogeneity of the material. Modulus, however, decreased with increase in replacement of POFA in the specimens tested under compression. It is concluded that Weibull distribution is suitable for analyses of the blended geopolymer system. While porous microstructure is mainly responsible for flexural failure, heterogeneity of reaction relics is responsible for the compression failure

Drying shrinkage and porosity of polymer modified concrete containing vinyl acetate effluents

The volume of waste generated from surface coating industries is of global concern. The disposal of this waste in the form of effluent has put enormous pressure on land and also poses as a health hazard when it leaches into soil and underground water. The study aims to examine the utilization of vinyl acetate effluents from water based paint factories as an admixture in concrete. Concrete specimens containing 0%, 2.5%, 5% and 10% of vinyl acetate effluents by weight of cement were prepared. The specimens were tested for drying shrinkage for 28 days and porosity was tested using mercury intrusion porosimetry. Findings show that concrete containing various proportions of vinyl acetate effluents manifests higher shrinkage behaviour compared to the control item. An investigation of pore size distribution reveals that polymer effluents have particles size larger than 50 nm which are categorize as macroporous in accordance to IUPAC classification. It can be concluded that adding polymer vinyl acetate effluents affects concrete deformation due to the condition of its pore structures. The utilization of this material may provide beneficial effect in terms of the durability performance of concrete and minimize environmental pollution

EFFECT OF MICRO-STRUCTURE AND MINERALOGICAL COMPOSITION ON THE WATER DEMAND AND SUPER PLASTISIZER CONTENT OF TERNARY BLENDED SELF-CONSOLIDATING PASTE

The Thirteenth East Asia-Pacific Conference on Structural Engineering and Construction (EASEC-13), September 11-13, 2013, Sapporo, Japan

Early strength characteristics of palm oil fuel ash and metakaolin blended geopolymer mortar

In this paper, the early strength behavior of Metakaolin and Palm Oil Fuel Ash (POFA) based geopolymer mortar was investigated for the purpose of exploring the utilization of POFA which is a waste material generated from production of palm oil. Geopolymer mortar was prepared by activating metakaolin combined with POFA at 0%, 30%, 40%, 50%, 60%, 70% and 80% replacement levels in NaOH and Na2SiO3 medium. The mortar specimens were tested for compressive strength at 3 and 7days. The maximum compressive strength at 3 and 7days are 65.264MPa and 68.863MPa respectively corresponding to a POFA replacement of 40%. A replacement of 80% POFA to 20% Metakaolin gave compressive strength as high as 26.174MPa and 30.791MPa for 3 and 7 days. It was also discovered that water demand of the system reduced with increase in POFA replacement. It is concluded that POFA addition to metakaolin can improve behavior of Metakaolin and POFA geopolymer system

Behavior of concrete with polymer additive at fresh and hardened states

Discarding waste materials from factories to landfills is becoming difficult lately as public awareness on their effects on earth is getting better. One of such material comes from paint factory (waste latex paint), which at the moment being tried as additive by many researchers. This paper presents results of laboratory work carried out on emulsion by-product polymer in order to evaluate its performance as an additive in concrete. Series of concrete mixes containing 1%, 2%, 3%, 5% and 10% polymer contents by weight of cement were prepared, cured and tested for workability, mechanical and durability properties at 7, 28 and 60 days. Test parameters include compressive, indirect tensile and flexural strengths, water absorption and chemical resistance. Results indicated that workability of the modified concrete reduced with increasing amount of polymer content. In addition, specimens mixed with 2% polymer performed better than other percentages. However, higher polymer content is necessary for better performance in durability aspects. Thus, while 2% of polymer is the optimum quantity for mechanical strength, durability is at best when this percentage is exceeded

Strength and durability characteristics of polymer modified concrete incorporating vinyl acetate effluent

Waste generation from surface coating industries brings about worsening of the environmental scenery and human health in the world. The production of these wastes is detrimental to surrounding areas in landfill or dumping spaces, therefore necessary action is required to minimize the unpleasant situation. This research is aimed at using waste generated from the manufacture of paint known as vinyl acetate effluent as an admixture in concrete. The material is rinse water taken from the cleaning process reactor. Concrete of 0% vinyl acetate effluent cured in water with those of 2.5%, 5%, 10% and 20% by weight of cement were produced and cured using Japanese standard. The specimens were tested for compressive strength, splitting tensile strength and durability at 3, 7 and 28 days. Findings show that incorporating of 2.5% of Vinyl acetate effluent improves strength properties of concrete. Higher resistance of water absorption and sulfate conditions were observed in polymer modified concrete. The study has shown that incorporating vinyl acetate effluent in producing polymer modified concrete could bring lights of using the waste material for sustainable and environmental preservations

Characterization of some key industrial waste products for sustainable concrete production

The use of environmentally friendly or green concrete to enable worldwide infrastructural development without increase in carbon dioxide (CO2) emission is at the focal point of the global issues concerning sustainability. Aside from the concerted efforts by the key players in the construction industry to successfully replace in part or in whole, the conventional Portland cement with green or eco-friendly cementitious materials, the challenges of ensuring that the so called green or eco-friendly concrete performs up to the required expectation has been the focus of many researches. This study therefore, provides an overview of the various processing techniques for the industrial waste materials as well as the determination of the physical and chemical characteristics of the powders prepared from the respective waste materials. The materials were characterized using BET surface area analysis, X-ray diffraction (XRD), Chemical analysis by X-ray fluorescence (XRF), 45-μm wet sieving, 75-μm and 150-μm dry sieving, Specific gravity using density bottle and reactivity index (RI). The results show that FA and PBC are very similar in terms of their physical and chemical characteristic in comparism with POFA. Notwithstanding, all the materials satisfy the basic requirements of the relevant ASTM specifications and also falls within the limit specified by ASTM C 618 for class F fly ash

Effect of vinyl acetate effluent in reducing heat of hydration of concrete

Waste generation especially in surface coating industries is a potential pollutant to the environment globally. Waste disposal in the form of recycling or reused has gained some recognition as a raw material in many kind of interested fields. This study is therefore, aimed at utilizing Vinyl acetate effluent generated from manufacturing process of paint as polymer modifier in concrete. The research highlights the influence of Vinyl acetate effluent on setting time and control of heat of hydration in concrete. Three specimens containing 0%, 2.5% and 5% of Vinyl acetate effluent by weight of cement were prepared in cubic moulds. The temperature rises due to heat of hydration in all mixes were recorded. Finding shows that incorporating Vinyl acetate effluent considerably delayed the setting time in cement paste and reduced the total temperature rise in polymer modified concrete. Therefore, addition of Vinyl acetate effluent polymer in concrete may improve the properties of concrete to some extent particularly in mass concrete production