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S. Ahmad et alii, Frattura ed Integrità Strutturale, 34 (2015) 524-533; DOI: 10.3221/IGF-ESIS.34.58 526 Chemical composition CaO Al 2 O 3 SO 3 SiO 2 Fe 3 O 4 MgO K 2 O Content (wt.%) 44 26.5 12 9.5 2.5 1.3 0.6 Physical characteristics Standard Average values Color - Light grey Density - 2,800 kg/m 3 Blain specific surface area UNI EN 196-6 480 m 2 /kg Initial setting time UNI EN 196-3 98 min Final setting time UNI EN 196-3 125 min Table 1 : Chemical and physical properties of cement [27] Property Appearance Specific gravity PH value Solid content Recommended dosage Value Amber 1.090 6.5 - 9.0 30.50% 1.5 wt% of cement Table 2 : Properties of super plasticizer [28] In the present research, the micro inert carbonized particles were synthesized from coconut shells. The coconut plant belongs to the family of palm trees with heights ranges up to 30 m [29]. Coconut is found in abundance all over the world especially in the tropical regions of Asia, Africa and Latin America. FAO statistics shows that for the year 2012, the coconut plants covering area of 12.13 million hectares produced about 62.42 million ton of coconut fruit [30]. Based on the structure of coconut fruit, it is generally divided in to three parts i.e. the innermost part or the coconut meat also known as copra, thick hard shell surrounding the coconut meat and the outermost layer of coconut coir. The shell surrounding the copra is a waste material and it is generally used for burning and other such low-level applications. For the synthesis of inert micro sized pyrolyzed particles, the coconut shells were dried at 105±5 o C for 24 h in oven to remove the absorbed moisture. The dried pieces of the coconut shells were pyrolyzed in an airtight quartz reactor under the constant flow of 99.9% pure argon gas under a pressure of 0.2 bar. The quartz reactor was heated with a constant rate of 1 o C/sec up to 850 o C and then the temperature was maintained there for 1 h. After the completion of pyrolysis, the pyrolyzed coconut shells were allowed to cool. Some quantity of the pyrolyzed coconut shell was annealed at 850 o C for 2 h to obtain more pure carbonized material. The pyrolyzed coconut shell (PC) and the pyrolyzed and annealed coconut shell (PCA) were then grinded to reduce the particle sizes up to micron scale. Figure 1 : Synthesis of micro carbonized particles from coconut shell by pyrolysis