EFFECT OF CONCRETE ALKALINITY ON CHLORIDE ION CONCENTRATION AT THE COLOUR CHANGE BOUNDARY DURING AGNO3 COLORIMETRIC MEASUREMENT
This paper investigates the effect of concrete alkalinity on chloride ion concentration at thecolour change boundary during AgNO3 colorimetric measurement. Equivalent silver nitratesolution (i.e. Ag-= Cl-) was added to mixed NaCI+NaOH solutions with differentconcentrations, then the amounts of precipitated AgCl and Ag2O were determined bychemical analyses, and the color of the precipitated products was determined. Results showedthat the amount of AgCl formed decreased linearly as OH-concentration or OH 1o Cl ratio ofthe solution increased, which are in agreement well with the theoretically calculated values.The colour of the precipitated reaction products changed from silver at low pH values to darkbrown at high pH values. When 0.035 and 0.1 mol/L AgNO3 solutions were sprayed ontofreshly split surface of mortar specimens after NT Build 492 testing, it was found that thecolour changed depth using 0.035 mol/L AgNO3 was larger than that using 0.1 mol/L AgNO3.Measured CI concentrations at the colour change boundary increased as the alkalinity ofconcrete increased.
Chloride ion concrete alkalinity silver nitrate colorimetric measurement
Caijun Shi Qiang Yuan Fuqiang He
College of Civil Engineering,Hunan University,Changsha,Hunan,China School of Civil Engineering and Architecture,Central South University,Hunan,China
国际会议
南京
英文
1389-1397
2008-10-13（万方平台首次上网日期，不代表论文的发表时间）