Hnub tim: 5, Sep, 2022

Cov nyhuv ntawm dej txo tus neeg sawv cev ntawm shrinkage cracking ntawm kev lag luam pob zeb:

Tus neeg saib xyuas dej txo qis yog cov khoom sib xyaw uas tuaj yeem muab ntxiv thaum lub sijhawm sib xyaw ua ke kom txo qis lossis txo cov pob zeb sib xyaw dej, txhim kho cov dej ntws ntawm cov pob zeb, thiab ua kom lub zog ntawm cov pob zeb. Kev xyaum tau ua pov thawj tias tom qab ntxiv cov dej reducer rau pob zeb, yog tias tsis tas yuav ua kom muaj zog, cov cement tuaj yeem txo qis heev, thiab cov compactness ntawm pob zeb tuaj yeem txhim kho. Yog li ntawd, dej txo tus neeg sawv cev yog ib qho tseem ceeb ntawm cov khoom siv ntxiv hauv kev lag luam pob zeb.

Txhawm rau txhawm rau txhim kho cov txiaj ntsig kev lag luam ntawm kev lag luam pob zeb, cov tuam txhab ua vaj tse nyiam siv cov dej txo cov neeg ua haujlwm nrog cov dej siab txo cov khoom los txhim kho lub zog ntawm cov pob zeb los yog txo cov cement ntau thiab txo cov nqi tsim khoom. Qhov tseeb, qhov no yog kev nkag siab yuam kev loj. Txawm hais tias kev txo dej yog qhov zoo los txhim kho lub zog ntawm cov pob zeb, kev txo cov dej ntau dhau kuj tseem cuam tshuam rau lub zog flexural ntawm pob zeb. Txawm hais tias qhov kev txo qis ntawm cov dej kom zoo yog qhov zoo los txo qis qis ntawm cov pob zeb, nws yuav tsum tau muab sau tseg tias thaum tsim cov pob zeb sib xyaw ua ke, cov dej-txo ua haujlwm ntawm kev ntxiv cov dej-txo tus neeg sawv cev tau raug coj mus rau hauv tus account, thiab dej. -binder ratio feem ntau yog tsim los kom tsawg. Kev siv dej yuav ua rau kom qhuav shrinkage ntawm pob zeb thiab ua kom cov pob zeb shrinkage.

Txawm hais tias lub zog compressive ntawm kev lag luam pob zeb tsis txo qis thaum cov cement cov ntsiab lus txo qis heev, lub zog tensile txo nrog qhov txo qis ntawm qhov ntim ntawm cov pob zeb hardened cement hauv cov pob zeb. Vim qhov txo qis ntawm cov cement, cov pob zeb cement slurry txheej yog nyias dhau, thiab ntau micro-cracks yuav tshwm sim hauv cov pob zeb. Yog lawm, micro-cracks tsis tshua muaj txiaj ntsig rau lub zog compressive ntawm cov pob zeb, tab sis kev cuam tshuam ntawm lub zog tensile thiab lwm yam khoom ntawm cov pob zeb tsis tuaj yeem kwv yees. Kev txo qis ntawm cov ntaub ntawv cementitious tseem yuav cuam tshuam rau elastic modulus thiab creep ntawm pob zeb, ua pob zeb ntau dua rau kev tawg.

Txhawm rau ua kom tiav, thaum tsim cov pob zeb ua lag luam, cov pob zeb txo qis thiab cov khoom siv cementitious yuav tsum tau txiav txim siab tag nrho, thiab tsis muaj qhov txwv tsis pub dej los yog txo cov khoom siv cementitious ntau dhau.