Idethi yokuthumela:1,April,2024
Ngokuvamile kunenkolelo yokuthi uma izinga lokushisa liphakeme, izinhlayiya zikasimende zizokhanga kakhulu i-ejenti yokunciphisa amanzi ye-polycarboxylate. Ngesikhathi esifanayo, izinga lokushisa liphezulu, kulapho kusobala khona ukuthi imikhiqizo ye-cement hydration izodla i-ejenti yokunciphisa amanzi ye-polycarboxylate. Ngaphansi kwethonya elihlangene lemiphumela emibili, njengoba izinga lokushisa likhuphuka, i-fluidity yekhonkrithi iba yimbi kakhulu. Lesi siphetho singasichaza kahle lesi simo sokuthi i-fluidity yekhonkrithi iyanda lapho izinga lokushisa lehla ngokuzumayo, futhi ukulahlekelwa kwekhonkrithi kukhuphuka lapho izinga lokushisa likhuphuka. Kodwa-ke, ngesikhathi sokwakhiwa, kwatholakala ukuthi uketshezi lwekhonkrithi lumpofu emazingeni okushisa aphansi, futhi lapho izinga lokushisa lamanzi okuxuba likhuphuka, uketshezi lwekhonkrithi ngemva kokwanda komshini. Lokhu ngeke kuchazwe ngesiphetho esingenhla. Kuze kube manje, kwenziwa ukuhlolwa ukuze kuhlaziywe, kutholwe izizathu zokungqubuzana, futhi kunikeze izinga lokushisa elifanele lokukhonkolo.
Ukuze ufunde umphumela wokuxuba izinga lokushisa kwamanzi kumphumela wokuhlakazwa kwe-ejenti yokunciphisa amanzi ye-polycarboxylate. Amanzi angu-0°C, 10°C, 20°C, 30°C, kanye no-40°C alungiselelwa ukuhlolwa kokuhambisana kwe-cement-superplasticizer.
Ukuhlaziywa kukhombisa ukuthi uma isikhathi sokuphuma komshini sisifushane, ukunwetshwa kodaka lukasimende kuqala kuyakhuphuka bese kuncipha njengoba izinga lokushisa likhuphuka. Isizathu salesi simo ukuthi izinga lokushisa lithinta kokubili izinga le-siment hydration kanye nezinga le-adsorption ye-superplasticizer. Lapho izinga lokushisa likhuphuka, lapho izinga lokukhangisa lama-molecule e-superplasticizer lishesha kakhulu, umphumela wokuhlakazeka kwangaphambi kwesikhathi uzoba ngcono. Ngesikhathi esifanayo, izinga le-hydration likasimende liyashesha, futhi ukusetshenziswa kwe-ejenti yokunciphisa amanzi ngemikhiqizo ye-hydration kuyanda, okunciphisa uketshezi. Ukwandiswa kokuqala kokunamathisela usimende kuthinteka umphumela ohlangene walezi zici ezimbili.
Uma izinga lokushisa lamanzi elixutshwayo lingu-≤10°C, izinga le-adsorption le-superplasticizer kanye nesilinganiso sokufaka usimende kokubili kuncane. Phakathi kwazo, i-adsorption ye-ejenti yokunciphisa amanzi ezinhlayiyeni ze-cement yisici esilawulayo. Njengoba i-adsorption ye-ejenti yokunciphisa amanzi ezinhlayiyeni zikasimende ihamba kancane uma izinga lokushisa liphansi, izinga lokuqala lokunciphisa amanzi liphansi, elibonakala ku-fluidity yokuqala ephansi ye-cement slurry.
Lapho izinga lokushisa lamanzi axutshwayo liphakathi kuka-20 no-30 ° C, izinga lokukhangisa le-ejenti yokunciphisa amanzi kanye nezinga lokugeleza likasimende liyakhula ngesikhathi esifanayo, futhi izinga lokukhangisa lama-athomu e-ejenti yokunciphisa amanzi landa kakhulu. ngokusobala, okubonakala ekwenyukeni kwe-fluidity yokuqala ye-slurry kasimende. Lapho izinga lokushisa lamanzi elixutshwayo lingu-≥40 ° C, izinga lokufakwa kukasimende likhuphuka kakhulu futhi kancane kancane liba yisici esilawulayo. Njengomphumela, isilinganiso sensalela sokukhangisa sama-molecule e-ejenti yokunciphisa amanzi (izinga le-adsorption kususwe izinga lokusetshenziswa) liyehla, futhi udaka lukasimende luphinde lubonise ukuncishiswa kwamanzi okwanele. Ngakho-ke, kukholakala ukuthi umphumela wokuqala wokuhlakazeka we-ejenti yokunciphisa amanzi ungcono kakhulu lapho amanzi okuxutshwa ephakathi kuka-20 no-30°C futhi izinga lokushisa likasimende liphakathi kuka-18 no-22°C.
Uma isikhathi sokuphuma komshini siside, ukunwetshwa kodaka lukasimende kuhambisana nesiphetho esamukelwa ngokuvamile. Uma isikhathi sanele, i-ejenti yokunciphisa amanzi ye-polycarboxylate ingakhangiswa ezinhlayiyeni zikasimende ezingeni lokushisa ngalinye ize igcwale. Kodwa-ke, emazingeni okushisa aphansi, i-ejenti encane yokunciphisa amanzi isetshenziselwa ukufakwa kukasimende. Ngakho-ke, njengoba isikhathi sihamba, ukwandiswa kwe-slurry ye-cement kuzokwanda ngokushisa. Khulisa futhi unciphise.
Lokhu kuhlolwa akubheki nje umphumela wezinga lokushisa, kodwa futhi kunaka umphumela wesikhathi kumphumela wokuhlakazwa kwe-ejenti yokunciphisa amanzi ye-polycarboxylate, okwenza isiphetho sicace kakhudlwana futhi sisondele eqinisweni lobunjiniyela. Iziphetho ezifinyelelwe yilezi:
(1) Emazingeni okushisa aphansi, umphumela wokuhlakazwa kwe-ejenti yokunciphisa amanzi ye-polycarboxylate unokufika kwesikhathi okusobala. Njengoba isikhathi sokuxuba sikhula, i-fluidity ye-cement slurry iyanda. Njengoba izinga lokushisa lamanzi okuxuba likhula, ukunwetshwa kodaka lukasimende kuqala kwanda bese kuncipha. Kungaba nomehluko omkhulu phakathi kwesimo sikakhonkolo njengoba uphuma emshinini kanye nesimo sikakhonkolo njengoba uthululwa esizeni.
(2) Ngesikhathi sokwakhiwa kwezinga lokushisa eliphansi, ukushisisa amanzi okuxutshwa kungasiza ekuthuthukiseni i-fluidity lag kakhonkolo. Ngesikhathi sokwakhiwa, ukunakwa kufanele kukhokhwe ekulawuleni izinga lokushisa kwamanzi. Izinga lokushisa likasimende liphakathi kuka-18 no-22 ° C, futhi uketshezi lungcono kakhulu uma luphuma emshinini. Vimbela ukwenzeka kokuncishiswa kwe-fluidity kakhonkolo okubangelwa ukushisa kwamanzi ngokweqile.
(3) Uma isikhathi sokuphuma komshini siside, ukunwetshwa kodaka lukasimende kuncipha njengoba izinga lokushisa likhuphuka.
Isikhathi sokuthumela: Apr-01-2024
