Kusanganikirana kwa madzi kuchepetsa wothandizira kuposa yachibadwa kusanganikirana kuchuluka ndi kangapo, ndipo chikoka pa ntchito konkire ayenera kutsimikiziridwa malinga ndi mmene zinthu zilili.
Pachiyambi choyamba, mu konkire yowonjezereka kwambiri, chifukwa chiwerengero cha madzi-binder ndi ≤0.3 kapena ngakhale chochepa kwambiri cha 0.2, nthawi zambiri chimasonyeza kuti chikhalidwe cha konkire sichimakhudzidwa ndi kuchuluka kwakuchepetsa madzi. Pofuna kukwaniritsa madzi abwino, madzi amachepetsedwa. Mlingo wa wothandizira nthawi zambiri amakhala 5-8 nthawi yanthawi zonse, ndiye kuti, mlingo wapolycarboxylic acidayenera kufika 5% -8%. Kwa konkire pansi pa C50, zomwe zili pamwambazi ndizodabwitsa. Komabe, zotsatira zoyesa zimasonyeza kuti mphamvu ya konkire pa msinkhu uliwonse imakula bwino pansi pa ndalamazi, ndipo mphamvu ya 28d ya konkire imakonzedwa ndi mphamvuyi kuposa 100MPa.
Chifukwa chake ndi chakuti: kubalalitsidwa kwakuchepetsa madzipa simenti ndi thupi adsorption.Madzi kuchepetsa wothandiziramamolekyu ndi adsorbed pamwamba pa simenti particles. Kupyolera mu chopinga wosabala ndi electrostatic repulsion, ndi flocculation dongosolo particles simenti ndi disintegrated ndi madzi ufulu anamasulidwa. , Potero kuwonjezera fluidity wa konkire, ndi chifukwa cha mawonekedwe ake apadera chisa woboola pakati, ndipolycarboxylic acidzochokerakuchepetsa madziimatha kuletsa tinthu tating'ono ta simenti kuti zisalumikizidwenso pakapita nthawi, chifukwa chake zimakhala ndi ntchito yabwino yosungiramo zinthu. Patapita nthawi, simenti hydration mankhwala kukulunga kwathunthukuchepetsa madzimamolekyu adsorbed pamwamba pa particles simenti. Pambuyo pakuchepetsa madzimamolekyu ndi otetezedwa, kubalalitsidwa kutha kwathunthu, ndiyeno alibenso zotsatira kapena chikoka pa konkire. Simenti nthawi zambiri imakhala madzi Mphamvu ya konkire imakula bwino.
Inde, chifukwa mkulu zilikuchepetsa madzi, ndende yakuchepetsa madzimamolekyu mu konkire ndi lalikulu. Mamolekyu ena ataphimbidwa ndi zinthu za simenti, mamolekyu atsopano amatsatiridwa pamwamba pa zinthu za simenti, kuletsa tinthu tating'ono ta simenti kuti tidutse mwachangu. Ma network amapangidwa, omwe amakulitsa nthawi yokhazikika mpaka pamlingo wina, koma makonzedwe a simenti ambiri sangapitirire 24h.
Mu nkhani yachiwiri, akuchepetsa madzipalokha imakhala ndi zinthu zina zochepetsera mpweya komanso kuchepetsa, ndipo kangapo kusakaniza mopitirira muyeso kumatha kukhala ndi zotsatira zoyipa kwambiri pakuchita konkriti. Nthawi zambiri, kuchuluka kwa chigawo chochedwetsa kumatsimikiziridwa molingana ndi kutentha kwa chilengedwe, zofunikira za uinjiniya ndi mlingo wamba wakuchepetsa madzi. Adsorption imakhudza hydration wamba wa zinthu cementitious. Pang'onopang'ono, nthawi yoikika imatalika kwambiri, ndipo poyipa kwambiri, konkire sikhala masiku angapo kapena kosatha. Nthawi zambiri, konkire yomwe yakhazikitsidwa kwa masiku a 2 kapena kupitilira apo, chifukwa cha kuchedwa kwambiri kwa njira ya hydration, mtundu ndi kuchuluka kwa zinthu za hydration zidzasintha, zomwe zimapangitsa kuchepa kwamphamvu kwa konkire. Zachidziwikire, kwa milu yapansi panthaka (nthawi zambiri 72-90h yoyambira) ndikumanga konkriti monga milu, zipewa, madamu, ndi zina zambiri, nthawi yayitali yokhazikika imafunika. Kawirikawiri, mlingo wa mphamvu uyenera kuwonjezeka moyenerera panthawi ya mapangidwe a chiŵerengero chosakaniza. Onetsetsani kuti mphamvu ya 28d ikukwaniritsa zofunikira pakupanga.
The air-entrainingkuchepetsa madzindi wapamwamba wosakaniza kangapo. Pamene mpweya wa konkire ndi yoyenera pa mlingo wamba kusanganikirana, okhutira mpweya adzakhala kwambiri kuchuluka pambuyo wapamwamba osakaniza kangapo. Konkire ya konkire imakhala yolemera modabwitsa, ndipo konkire imakhala yopepuka komanso yoyandama pamene yafosholo, yomwe imakhala yoopsa Pamene konkire imakhala yotayirira komanso imakhala ngati buledi, mphamvu ya konkire imachepetsedwa kwambiri.
Munthawi yachitatu, ngakhale atakhala ndi vutokuchepetsa madzipalokha alibe mpweya-entraining ndi retarding mtundu, pambuyo kuwirikiza kawiri, ngati kumwa madzi si kusinthidwa mu nthawi, workability wa konkire mwatsopano akhoza kuonongeka kwambiri, kuchititsa katulutsidwe kwambiri. Madzi, tsankho, kulanda pansi, kuumitsa, etc., ndi osauka ofanana ndi bata pambuyo kuthira, ndi delamination mkati, zomwe zimabweretsa kuwonjezeka madzi-to-binder chiŵerengero cha konkire kuzungulira zitsulo kapamwamba, ndi kuchepa mphamvu. , zomwe zimapangitsa kuti chitsulocho chigwire mwamphamvu kwambiri. Kuchuluka kwa magazi omwe amayamba chifukwa cha kusakaniza kwakukulu kumawonekeranso pamwamba pa konkire ndi zigawo zomwe zimagwirizana ndi formwork, zomwe zimabweretsa kuchepa kwa mphamvu za zigawozi, ndi zolakwika zambiri monga ming'alu, zisa, ndi pockmarked pamalo sachedwa kuonekera nkhungu kuchotsedwa, zomwe zimapangitsa konkire mphamvu kukana kukokoloka kunja Kuchepetsa kwambiri, kwambiri zimakhudza kulimba kwa konkire.
Nthawi yotumiza: Dec-02-2021
