Matsayin metakaolin a cikin siminti

(1) Inganta ƙarfin siminti da turmi, ƙarfi mai yawa yana ɗaya daga cikin alamun siminti mai inganci. Ɗaya daga cikin manyan manufofin ƙara metakaolin shine inganta ƙarfin turmi da siminti na siminti.

Poon da abokan aikinsa (2001) sun gudanar da gwaje-gwajen ƙarfin matsi a kan siminti tare da rabon siminti na ruwa na 0.3, wanda aka shirya ta hanyar maye gurbin simintin Portland da kashi 0-20% (ƙasa mai yawa) na kaolin da silica foda. Sakamakon ya nuna cewa ƙarfin matsi na siminti mai ɗauke da kashi 5% zuwa 20% na kaolin ya fi na siminti mai ma'ana a kowane zamani, inda siminti mai ɗauke da kashi 10% na kaolin ya nuna ƙaruwar ƙarfi da kashi 20% a cikin kwanaki 28 da 90 idan aka kwatanta da siminti mai ma'ana. Siminti mai ɗauke da kashi 5% zuwa 10% na siminti shi ma ya nuna ƙaruwar ƙarfi da kashi 20% a cikin kwanaki 28 da 90 idan aka kwatanta da siminti mai ma'ana. Ƙarfinsa a 28d da 90d yayi daidai da na simintin kaolin, amma ƙarfinsa na farko ya yi ƙasa da siminti mai ma'ana. Bincike ya nuna cewa wannan na iya alaƙa da tsananin haɗuwar foda na silicon da aka yi amfani da shi da rashin isasshen warwatsewa a cikin siminti mai ma'ana.

(2) Li Keliang et al. (2005) sun yi nazarin tasirin zafin calcination, lokacin calcination, da kuma yawan SiO2 da A12O3 a cikin kaolin akan aikin metakaolin don inganta ƙarfin simintin siminti. An shirya siminti mai ƙarfi da polymers na ƙasa ta amfani da metakaolin. Sakamakon ya nuna cewa lokacin da abun cikin kaolin ya kai 15% kuma rabon simintin ruwa ya kai 0.4, ƙarfin matsi na kwanaki 28 shine 71.9 MPa. Lokacin da abun cikin kaolin ya kai 10% kuma rabon simintin ruwa ya kai 0.375, ƙarfin matsi na kwanaki 28 shine 73.9 MPa. Bugu da ƙari, lokacin da abun cikin metakaolin ya kai 10%, ma'aunin aikinsa ya kai 114, wanda ya fi adadin foda silicon girma da kashi 11.8%. Saboda haka, ana kyautata zaton ana iya amfani da metakaolin don shirya siminti mai ƙarfi.

Qian Xiaoqian et al. (2001) sun yi nazarin dangantakar matsin lamba da matsin lamba na siminti tare da yawan kaolin na 0, 0.5%, 10%, da 15%. Sun gano cewa tare da ƙaruwar yawan kaolin, matsin lamba mafi girma na ƙarfin matsin lamba na siminti ya ƙaru sosai, kuma ƙarfin ƙarfin juriya ya kasance ba a canza shi ba. Duk da haka, ƙarfin matsin lamba na siminti ya ƙaru sosai, kuma rabon ƙarfin matsin lamba ya ragu daidai da haka. Lokacin da adadin kaolin ya kai 15%, ƙarfin juriya da ƙarfin matsawa na siminti sune 128% da 184% na simintin da aka ambata, bi da bi.

Cao Zhengliang da abokan aikinsa (2004) sun gano a cikin bincikensu kan tasirin ƙarfafawar foda na metakaolin mai ƙarfi akan siminti cewa, a ƙarƙashin ruwa iri ɗaya, turmi mai ɗauke da kashi 10% na metakaolin ya ƙara ƙarfin matsi da ƙarfin lanƙwasa da kashi 6% zuwa 8% bayan kwana 28. Ƙarfin farko na siminti da aka haɗa da metakaolin ya fi sauri fiye da na siminti na yau da kullun. Idan aka kwatanta da simintin ma'auni, simintin da ke ɗauke da kashi 15% na metakaolin yana da ƙaruwa da kashi 84% a cikin ƙarfin matsi na axial na 3D da ƙaruwa da kashi 80% a cikin ƙarfin matsi na axial na 28d, yayin da simintin roba mai tsauri yana da ƙaruwa da kashi 9% a cikin 3D da ƙaruwa da kashi 8% a cikin 28d.

Huang Zhan da abokan aikinsa (2008) sun yi nazarin tasirin bambancin rabon haɗakar metakaolin da slag akan ƙarfi da dorewar siminti. Sakamakon ya nuna cewa ƙara metakaolin zuwa simintin slag yana inganta ƙarfi da dorewar simintin. Matsakaicin rabo na slag zuwa siminti yana kusa da 3:7, wanda ke haifar da ƙarfin siminti mai kyau. Bambancin baka na simintin composite ya ɗan fi na simintin slag guda ɗaya, saboda tasirin tokar dutse mai aman wuta na metakaolin. Ƙarfin tsagewansa ya fi na simintin ƙwallo.

Yang Fengling et al. (2011) sun yi amfani da daidai adadin metakaolin, tokar tashi, da slag don maye gurbin siminti, sannan aka haɗa metakaolin daban-daban da tokar tashi da slag don shirya siminti. An yi nazarin iya aiki, ƙarfin matsawa, da juriyar siminti. Sakamakon ya nuna cewa lokacin da aka yi amfani da kaolin don maye gurbin kashi 5% zuwa 25% na siminti daidai gwargwado, ƙarfin matsawa na siminti a kowane zamani ya inganta; Lokacin da aka yi amfani da kaolin daidai gwargwado don maye gurbin siminti da kashi 20%, ƙarfin matsawa a kowane zamani ya dace. Ƙarfin da ke a 3d, 7d, da 28d ya fi 26.0%, 14.3%, da 8.9% sama da na siminti ba tare da an ƙara kaolin ba, bi da bi. Wannan yana nuna cewa ga siminti na nau'i na II na Portland, ƙara metakaolin na iya inganta ƙarfin siminti da aka shirya.

Zhang Chengbo da abokan aikinsa (2012) sun yi amfani da slag na ƙarfe, metakaolin, da sauran kayayyaki a matsayin manyan kayan aiki don shirya simintin geopolymer don maye gurbin simintin gargajiya na Portland, cimma burin kiyaye makamashi, rage amfani, da kuma mayar da sharar gida ta zama taska. Sakamakon ya nuna cewa lokacin da abun ciki na ƙarfe da tokar tashi suka kasance kashi 20%, ƙarfin tonon gwaji a cikin kwanaki 28 ya kai matsayi mai girma (95.5MPa). Yayin da adadin slag na ƙarfe da aka ƙara yana ƙaruwa, yana iya taka rawa wajen rage raguwar simintin geopolymer.

Chen Guocan (2010) ya ɗauki hanyar fasaha ta "Portland cement+active mineral admixture+high-efficiency water reducer agent", fasahar simintin ruwa mai maganadisu da tsarin shiri na gargajiya, kuma ya gudanar da gwaje-gwajen shiri akan simintin dutse mai ƙarancin carbon mai ƙarfi ta amfani da kayan da aka samo daga gida kamar duwatsu da slag. Sakamakon ya nuna cewa adadin metakaolin da ya dace shine 10%. Matsakaicin nauyin gudummawar siminti zuwa ƙarfi na kowace naúrar simintin dutse mai ƙarfi ya kai kusan sau 4.17 na siminti na yau da kullun, sau 2.49 na siminti mai ƙarfi (HSC), da sau 2.02 na simintin foda mai amsawa (RPC). Saboda haka, simintin dutse mai ƙarfi mai ƙarfi wanda aka shirya tare da siminti mai ƙarancin allurai shine alkiblar ci gaban siminti a zamanin tattalin arzikin ƙasa mai ƙarancin carbon.

(3) Bayan ƙara kaolin mai juriya ga sanyi ga siminti, girman ramin simintin yana raguwa sosai, wanda ke inganta zagayowar daskarewa da narkewar simintin. Feng Naiqian (2002) ya gano cewa a ƙarƙashin wani adadin zagayowar daskarewa da narkewa, tsarin roba na samfurin siminti tare da abun ciki na kaolin 15% a kwanaki 28 ya fi na simintin da aka ambata a kwanaki 28. Amfani da metakaolin da sauran foda na ma'adinai masu ƙarfi a cikin siminti na iya inganta aikin dorewar siminti sosai.