හොදම සිමෙනති වර්ගේ මොකක්ද ????

shaminda peiris

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  • Mar 12, 2014
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    පානදුරේ
    කොන්ක්‍රීට් වැඩවලට ටෝකියෝ හරි මහවැලි මෙරින් හරි ගනින්.අනිත් වැඩවලට ඕන එකක් ගනින්.
     

    senewimala1988

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  • Dec 5, 2007
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    Machn, umba oya daala thiyena Cement type deka balapan. E deke SLS dekak thiyenne. Ekak SLS 107. Anith eka wena ekak. E kiyanne Cement types dekak. SLS 107 kiyanne api issara idan use karana Ordinary Portland Cement kiyana eka. Anith eka Portland Limestone Cement. Eke amu hunu gal podi gaanak mix karala thiyenava. Eka water retaining structures walata thamai wadiya hoda naththe. Foundation walata avulak ne machn.
    E hinda umba InSee(Sansta), Tokyo Super, Ultratec cemet brands walin kemathi ekakin mama udin kiyapu type deken oni ekak use karapan. :)

    PS.
    Machn. Mama passe dakke. Umbe 2nd cemet eka Pozzolana cemet ekak. Eka use karanna epa. Therumak ne. Eka oni wenne mass concrete walata, such as raft foundations. :)
     
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    senewimala1988

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    Aligning with the global developments, Sri Lanka Standards Institution (SLSI) revised two available SLS standards, namely SLS107 for Ordinary Portland Cement (OPC) and SLS515 for Masonry Cement in 2002 and 2003, respectively. Then, with the European Union’s introduction of EN197-1:2000 for the new category of cement called "Common Cements" in 2000, the SLSI considered it opportune to develop new Sri Lankan standards aligning with this latest international standard. Consequently, SLSI introduced in 2003 two SLS standards for two categories of "Common Cements":

    * SLS1247:2003 for Blended Hydraulic Cements

    * SLS1253:2003 for Portland Limestone Cement

    Both these cements - also called "composite cements" - are highly recommended for concrete applications although they can also be used as general-purpose cements. When used for concrete, these cements improve both fresh state properties such as workability and hardened state properties such as long-term strength and durability.

    SLS1247:2003 for Blended

    Hydraulic Cements

    A blended hydraulic cement is a blend of Ordinary Portland Cement (OPC) and pozzolanic material (such as fly ash) / blast furnace slag. It is manufactured either by intergrinding Portland cement clinker, pozzolanic material/slag and gypsum or by blending pozzolanic material/slag with Ordinary Portland Cement.

    This cement is of two types, depending on the main constituent used for blending with Portland cement or Portland cement clinker. The main constituents of Type I (Portland pozzolanic cement) are clinker (65 to 94% by mass) and pozzolanic material (6 to 35%). The pozzolanic materials allowed by the standard are natural pozzolana, paddy husk ash, fly ash and burnt shale. The main constituents of Type ll (Portland slag cement) are clinker (65 to 94%) and blast furnace slag (6 to 35%).

    SLS1253:2003 for Portland

    Limestone Cement

    Portland Limestone Cement is manufactured either by intergrinding Portland cement clinker with limestone or by blending finely ground limestone with OPC. The main constituents of Portland Limestone Cement are clinker (85 to 94% by mass) and limestone (6 to 15%). The calcium carbonate content of the limestone should be greater than 75%.

    Specification parameters and their effect on cement quality

    The specification parameters given in the two standards (i.e., SLS1247:2003 and SLS1253:2003), their effect on cement quality and the values specified in the two standards are given below:

    Compressive strength

    Compressive strength at the age of 3 days is important with respect to pre-cast applications and early removal of moulds (formwork). Compressive strength at 28 days is important with respect to safety, economy and durability of the structure. Both standards specify that compressive strength at 3 days should be greater than 20MPa and that at 28 days should be between 40 and 62.5MPa. These requirements are identical to the values given in SLS107:2001, the SLS standard for OPC.

    Setting time

    Initial setting time allows adequate time to work with mortar or concrete while final setting time avoids abnormal retardation. Both standards require that the initial setting time be greater than 45 minutes and the final setting time be less than 10 hours.

    Soundness

    Two tests on soundness - Le Chatelier and autoclave tests - ensure the limited presence of MgO and free CaO, which cause unsoundness in cement. The hydroxides they produce by slow reaction with water cause expansion in the hardened cement paste, resulting in its disruption. Both standards specify that the Le Chatelier value be less than or equal to 10mm and the autoclave value be less than 0.8%.

    Chemical requirements

    Presence of SO3 and chlorides should be limited as they contribute to late ettringite formation and corrosion of steel reinforcement respectively. Both standards specify that the SO3 content be less than 3.5% and chloride content be less than 0.1%.

    Fineness

    Fineness of cement particles affects strength development and workability. SLS1247:2003 does not specify fineness while SLS1253:2003 specifies that the fineness value be greater than 3300 square centimeters per kilogram.

    Loss on ignition

    Loss on ignition indicates the presence of CaCO3, CaSO4 and water, enabling the checking of the percentage addition of calcareous main or minor constituents and aeration of cement. SLS1247:2003 does not specify loss on ignition while SLS1253:2003 specifies that loss on ignition be less than 7.5%. Loss on ignition is however not an application parameter.

    Good for the construction industry

    Now that the SLS standards on composite cements are in place, the Sri Lankan construction industry can reap the benefits offered by these new special application cements by way of enhanced concrete construction.
    Machn. Where did u get this information? Hoda description ekak. However oya standards ehema revise welaa thiyenava. SLS 107 ehema latest eka 2015 version eka. And PLC evva use karanna bari structures ICTAD specifications wala deela thiyenava :)
    BTW, thanx 4 da info :)
     

    MathTricks

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    Holcim Sanstha concrete walata gnne epa

    sanstha pavichchi kranne ne concrete walata. hunugal wadi nisa cracks athi wenna puluwn. Ultratech thama hodama lankawe thiyena ewalin.

    portland pozzolana cement hodai. meke strength eka enna kal yanawa. but OPC walata wada hodai. early steangth eka adui.

    Apit OPC walata 10-20% fly ash mix krala one nm cost eka adu kara gnnath puluwan. ethakota workbility eka adu wenw
     

    senewimala1988

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    sanstha pavichchi kranne ne concrete walata. hunugal wadi nisa cracks athi wenna puluwn. Ultratech thama hodama lankawe thiyena ewalin.

    portland pozzolana cement hodai. meke strength eka enna kal yanawa. but OPC walata wada hodai. early steangth eka adui.

    Apit OPC walata 10-20% fly ash mix krala one nm cost eka adu kara gnnath puluwan. ethakota workbility eka adu wenw

    සංස්ථා හොදයි කියන්නෙ හයි වෙන්න වෙලා යන හින්දා වැඩ කරන්න ලේසි හන්දා
    oya kiyanne machn Portland Limestone Cement (PLC) gena.
    Unge Ordinary Portland Cement (OPC) ekakuth thiyenava. Issara idan aave eka :) hunugal thiyena PLC eka sansta vitharak nemei, thava companies walath thiyenava. eka wenama standard ekakata karanne. not SLS 107 :)
     
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    SHEHAN_GIWANTHA

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    Foundation, floor concrete & column okkoma damme “Mahawali Marine” walin
    Slab eka danna inne “Tokyo Super” walin

    Note:
    INSEE Mahaweli Marine. INSEE Mahaweli Marine cement has been a pioneering product of the local construction industry since 1980, used as the base product for the construction of Victoria Dam and the Mahaweli Development Program, it is one of Sri Lanka's largest multi-purpose development programs to date.