Comparative Study of Chemically and Mechanically Activated Clay Pozzolana (original) (raw)
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Influence of Clay Pozzolana on Some Properties of Portland Limestone Cement
Construction Research Congress 2014, 2014
For many years in the Ghanaian construction industry, ordinary Portland cement (OPC) has been known to be the main binding agent widely used for construction. However in recent times the cement market in the country has seen the entrance of Portland Limestone cement (PLC). Data regarding ordinary Portland cement and clay pozzolana (CP) is available but with PLC-CP mixes, there remains absolutely no data. In this work PLC was incorporated with different percentages of CP ranging between 10% and 40%. The CP was characterised based on physical, chemical and mineralogical properties. Technical parameters such as normal consistency and setting times were analysed on the formulated paste whilst strength analysis were performed on the batch mixes of formulated mortars. The results indicated that both the consistency and setting times appreciated as compared with only PLC paste whilst the compressive strength of PLC mortars incorporated with CP fell slightly lower than the controlled PLC mortar.
Study and Review of Properties and Applications of Portland Pozzolana Cement
Asean Journal Of Science And Engineering, 2021
The artificial pozzolana materials used in the manufacturing of PPC such as fly ash, silica fume, rice husk, blast furnace slag, are actually industrial waste, which is produced in large amounts. These artificial pozzolana materials when used in concrete can reduce consumption of natural resources, diminish the effect of pollutants in the environment and it is economical and reliable. The main objective of this paper is to focus on the properties and applications of Portland Pozzolana Cement and make effective use of different industrial by-products in the manufacturing of cement. We found that both PPC and ordinary portland cement (OPC) are commonly used types of cement in construction. Nowadays, PPC is used as a substitute for ordinary Portland cement (OPC cement). Since PPC contains pozzolanic materials, it helps to enhance the strength of concrete. The quantity of PPC required in making the concrete is less when compared to OPC. PPC is a green material that contributes towards sustainable development.
Utilization of pozzolanic materials in cement manufacturing offers an alternative method of preparing cement with increased durability of concrete and better mechanical properties. It also reduces the high energy requirement associated with production of Ordinary Portland Cement (OPC). This study investigated the use of natural pozzolans within Busia County, that is; rice husks ash (RHA), bagasse ash (BA), clay and broken bricks (BB) to make Pozzolana Cement (PC). Three types of pozzolana ashes were made and characterized using electrical conductivity tests, X-Ray Fluorescence and X-Ray diffraction analysis. The Pozzolans comprised of: RBC-mixture of RHA, ground BB and clays, BBC-had BA, ground BB and clay and RBBC-RHA, BA, ground BB and clays. The binder was prepared by mixing each Pozzolana ash with lime at different intervals. Mortar was tested for physical cement tests. Chemical composition tests showed that the Pozzolans studied were good pozzolanic material for use in supplementary cement production, with a combined percentage of Silica (SiO 2), Iron Oxide (Fe 2 O 3), and Alumina (Al 2 O 3) of more than 70%. SiO 2 had the highest percentage. The levels of MgO were less than 2.8%. The electrical conductivity test done showed that BA had the highest rate of decrease in the electrical conductivity followed by RHA, BB and least was clay. In addition, optimal Pozzolana: Lime ratio was 2:1, and the best blend of the pozzolana ashes was RBC, which gave a 28 days compressive strength of 2.88N/mm 2 cured in air. The optimal Pozzolana: Lime binder had an initial setting time of 130 minutes with a final setting time of 677 minutes indicating that the binder took a longer time to attain the peak hydration as compared to PPC cement. The study provides an alternative method for making cement which is ecofriendly, cheap and uses locally available materials in Kenya. It also has positive input on solving waste disposal problem which is of great environmental and health concerns.
Mechanical and durability properties of cement mortar with Algerian natural pozzolana
Journal of Materials Science, 2006
This paper presents a study of the properties and behaviour of cement mortar with natural pozzolana from Algeria. The effect of level of addition of natural pozzolana (0, 10, 20, 30, and 40%) on the mechanical properties of mortars at different ages as well as the effect of curing environment and the period of initial curing on the mechanical properties were investigated. The performance of natural pozzolana cement exposed to three aggressive solutions (acids, sulphate, and chloride) is also analysed. The results indicate that the strength of pozzolanic cement is lower than that of plain Portland cement at early ages, but can reach the same order of strength at longer curing periods. The enhancement of the resistance to acid and sulphate attack as well as to chloride ion penetration of natural pozzolanic cement is also demonstrated.
Pozzolanic properties of calcareous clay in blended cement pastes
The properties of mortar containing blends or mixtures ol Portland cement clinker, calcined clay and gypsum were examined. The mortars which consist of 80% of Portland clinkel 15% ol calcined clay and 5olo of gyprum were prepared and compared, in terms of setting times and compressive strengths, lo clay-lree control mortar with 95% of Portland clinker and Selo of gypsugn. Four clay samples were prepared as pozzolana for lhe analysis. The initial setting times of the pozzolana cdment varied from 159-170 minutes compared to 157-160 minutes for the control mix while the final setting times lor the pozzolana cement and the control cement varied trom 232-240 and 236-245 respectively. The compressive strengths for 3-days, 7'days and 28-days for both types of mortars show very close and similar resemblances with the 28-days strength of the pozzolana cement having values in the range of 47-Sg N/mm2 and the control cement having values in the range of 44-55 N/mm'z.
Experimental Studies on Strength and Durability of Mortars Containing Pozzolonic Materials
This paper discusses the effects of using different pozzolonic materials as a partial cement replacement material in mortar mixes. An experimental study of mortar made with Ordinary Portland Cement (OPC) and 12% of OPC, replaced by different pozzolanic materials such as fly ash, rice husk ash, silica fumes, Calcined Clay (Grog) and Slag (GGBS) were tested for the strength and durability properties to determine the effect of these materials on mortar properties and compared to control mortar mix.
Influence of Calcined Clay Pozzolana on Strength Characteristics of Portland Cement Concrete
International Journal of Materials Science and Applications, 2014
The paper presents results of a study on concrete mixes containing two types of calcined clay pozzolanas obtained from Mankranso and Tanoso for structural application. Mankranso sample is labeled Type I whilst Tanoso also labeled as type II.Both clay samples were analysed to determine their physical and geotechnical properties whilst the chemical composition of the calcined clay samples analysed. Portland cement was replaced with 0%-25%Type I and 0-30% of Type II pozzolanas to formulate binder pastes and concretes. Setting times and normal consistency test were determined on the formulated binder paste. Three grades of concrete (25N/mm 2 , 30N/mm 2 and 40N/mm 2) containing pozzolana were prepared and their workability, density, compressive strength and flexural strength investigated against the plain concrete. Concretes with clay pozzolana had delayed setting times and lower densities. They also exhibited a reduction in compressive and tensile strength development at early age (7 days), with an average drop of 6 percent in compressive strength for all grades. However, the compressive and tensile strengths beyond 28 days notably exceeded the control un-blended mixes. This study recommends up to 20% clay pozzolana content of both Types I and II for concrete grades of 25N/mm 2 , 30N/mm 2 and 40N/mm 2 .
Use of clay as a pozzolona in high strength Portland cement and its thermal activation
Chinese Journal of Geochemistry, 2010
In this investigation local clay from Cherat mines, Nowshera District, NWFP, Pakistan, has been tested as a pozzolanic material in high strength Portland cement. Thermal treatments were performed as a means of activation of the clay. It was found that thermal treatment of the clay can increase its pozzolanic activity. Different blended mortars, containing different amounts of clay, activated at different temperatures were studied for compressive strength, consistency, and setting times. It was concluded that the mechanical properties of the blended cements were mainly governed by the percentage of incorporation of the calcined clay. Blended cement composition has been formulated, with optimal results of 20% calcined clay at a temperature of 600℃.
An Experimental Study on the Strength of Mortar due to Filler Effect of Pozzolanic Materials
The filler effect of pozzzolanic materials is defined as proper arrangement of small particles into the microstructure that fill the voids and contribute towards improvement of compressive strength without any chemical reaction. This effect of pozzolan plays a vital role for the production of high strength mortar. The filler effect is dominating when pozzolan particles are in chemically inactive form. The individual contribution of physical and chemical effect in concrete and mortar still not determined. Several studies have been found in the published literature on finding the filler effect of pozzolans by replacing cement with chemically inactive materials which size is same as pozzolans. The chemically inactive materials used in previous studies are carbon black, limestone filler and ground river sand, which used bigger range size of replacement percentages (like 5%, 10%, 15% or 10%, 20%, 30%etc). However in this study, lower range size of replacement percentages (like 2.5%, 5%, ...
Pozzolanic Characteristics of a Natural Raw Material for Use in Blended Cements
2009
In this study, the potential use of a natural raw material in the manufacture of blended cements was investigated. Mineralogical, petrographic and chemical analyses of the samples showed that the natural raw material was a porphyritic volcanic rock close to trachyandesite composition with a SiO 2 +Al 2 O 3 +Fe 2 O 3 content of 79.86%. Further experiments were also designed to determine the physical properties and pozzolanic activity of the raw material. The mortar samples, made with a binder of ground trachyandesite and lime, developed compressive and flexural strengths of 2.5 and 3.3 times respectively higher than those required for a natural pozzolan. Further tests revealed that when the ground trachyandesite replaced 30% w/w of Portland cement, the blended cements produced had the desired physical and chemical characteristics with compressive strengths higher than 32.9 N/mm 2 . These findings suggest that this material can be used in the production of blended cements.