CEE Oct-Dec 2002

domestic markets. In projects where 12 uropca n consultants specify cement complying with EN standards. cements are specially manu t~1cturcd. Chi na has adopted EN Standard Speci fi cati ons 9) Difference between EN standards ond Indian standards: EN standard calls for following ( I) physical and (2) chemical requirements: 1- a) Physica l requirements Strength ( 2 days and 28 days) on prism mould Size: 40 x 40x 160mm. Depending upon 2 days and n days strength, they have different strength class in different type of cements. For measuring comp ressive stre ngth, CEN standard sand is used and cement mortar is prepared with fixed water/ cement ratio in mortar mix er keeping temperature in the Jab 20+/ -2 degree celsius and humidity greater than 50% for compaction or cement mortar in the mould- jolting apparatus. b (i) Whereas, Indian standards measure compressive strength at 3/7 and 28 clays on cement mortar cube of varying wa ter/ cement ratio (wa ter requirement depends upon normal consistency) Size: 70.7 111111, mortar is prepared by hand mixing. Lab temperature 27+/– :2 degree celsius and humidity +/ -65%. For compaction of cement mortar in the mould a vibrating machine is used. b (ii) In Indian s tandard compressive strength of cement is measured with Ennore sand and for compact ing the mortar cube , a vibrating machine is used after mortar is prepared by hand mixing. Mortar cubes are tested in compression testing machine conforming to class two type ofmachine. No special requirement for platens roughness index as wei I as planocity is required. b (iii) EN standard cal ls for very stringent calibration of testing equipment, such as calibration of pri sm moulds for length , width, depth, platen th ickness, flatness tolerance, perpendicular tolerance, roughness texture, etc . For compressive te sting machine EN calls for calibration of platen with, length, planocity, surface 'texture, speed load, etc . For mortar mixer EN calls for calibration of bowl and blade gap and !ow and high speed rotary and planetary motion and for jolting apparatus calls ca libration of gap between Jug and stop and counter. c) EN standard s do not spec ify fineness as an essential physical property contrary to Indi an standard. For so undness only Le Chatelier expansion is mea sured in EN standard whereas Indian standa rd s specify both Le Chatli er and Autoclave expansions. d) ln EN standard on ly initial se tting time is mea sured whereas th e Indian standard spec ifies both initial and fin al setting time. 2 a) In Chemical parameters, in EN standard , LOI, IR and SO, . MgO and C hl oride are measured whereas in the Indian 45 standards, these parameters are essential in addition to LSF and Alumina Modulus. 10) European Ce 111en t Cert if/cat ion - C 01~[or 111 i ty Evaluation Consists offollowing steps in brief:- i) Auto Control Testing by the Manufacturer. ii) Audit Sample Testing by the Manufactu rer and approved testing laboratory iii) Facto ry Production Control Operations by the Manufacturer's Works Quality Manual The Assessment is done by an approved certification body and on conformity all the three no rm s above, 12C Certification is awarded to the factory for the particular type of cement After obtaining EC Certification, a cement plant can export the particular type ofCement accredited to any European Country mentioned in item "(8)' above and in corporate CE marking on the product for acceptability. 11) Sourcing of Sand und Equipment:- In India, to conduct tests as per EN Stand ard, no indigeno us equipment and materi a ls a re current ly avai !able. These eq uipment, such as Prism Moulds, Mortar Mixer Machine. Compression Testing Ma chin e (C lass 1), Jolting Apparatus, and Initial Setting Time Apparatus need to be imported. Efforts are going on to produce CEN sand equivalent from indi genous sa nd, but, presently even. CEN sand is also imporied at hi gh cost.