Research On And Preparation Of The Anti-radon Coating With High Performance And Application Test In An Underground Engineering

The underground engineerings are high radon concentration, highhumidity and inclosed, the traditional anti-radion coating can’t be usedin the underground engineering. Because, the drying time is long, theVOC is high, the radon mitigation effi ciency and the durability aren’tgood. In the subject, we develop an anti-radon coating with highperformance in order to solve these problems. In an undergroundengineering, we obtain a very good effect by used the anti-radoncoating with high performance.We make out an anti-radon coating with high performa nce bychoosed appropriate the mo dified polymer emulsion, the anti-radonfunctional material, pig ment, filler and additive in the subject. We fi n dthat the basic performances are very good of the anti-radon coatingwith high perfor mance which isn’t metamorphic when store24h in the-18±2℃; the performances are stable when freeze-thaw cycles5ti mes;the scrub resistance is more than20000when the coating thickness is200μm; the covering power is105g/m2. By studying on the radonmitigation perfor mance find that the radon mitigation efficiencyachieves to the best when the dosage of the defoamer is0.3%±0.05%,the radon mitigation efficiency increased with increasing the coatingthickness and when the coating thickness is2.0±0.1mm, the radonmitigation efficiency is98.96%, but, the radon mitigation efficiencydoesn’t obviously rise when the coating thickness is more than2.0mm.The drying time of the anti-radon coating with high performance ismuch shorter than the ordinary anti-radion coating, but in order toulteriorly reduce the drying time, we add5wt%ash-calcium, because it doesn’t affect the radon mitigation performance and the stability. Theformaldehyde content is38.4mg/kg, Pb content is1.6mg/kg, Cd, Cr andHg content is less than0.1mg/kg and don’t find other VOC, so, theenvironmental protection perfor mance is very well of the anti-radoncoating with high performance. When the coating thickness is2.0±0.1mm and the testing time of the water resistant is less than144h,the paintcoat isn’t abnormal and the bond strength is more than0.3Mpawhen the testing time is less than196h. When the coating thickness is2.0±0.1mm and the testing time of the alkali resistant is less than72h,the patincoat isn’t abnormal and the bond strength still can achieve0.37Mpa when the testing time is120h. By studying on the agingresistance find that the toleration is very well when face the high radonradiation, the high damp-heat and the mould. Whe n the radonconcentration is86456Bq/m3and testing ti me is one year, the lowestradon mitigation efficiency is98.81%. The average radon mitigationefficiency can still achieve96.44%when hydrothermal aging49days.The average radon mitigation efficiency can still achieve95.92%whenmould aging84days. When it is hydrother mal aging49days and mouldaging84days, the lowest radon mitigation efficiency is94.21%. But, itonly reduces4.60%comparied with before the aging resistance, notmore than5%of the expected.The anti-radon coating with high perfor mance is practicalapplication in an underground engineering of Guangzhou. The resultshows that the anti-radon coating with high perfor mance is drying fast,no peculiar smell, no accumulation of the VOC and the radon mitigationefficiency is very well. The radon mitigation efficiency can reach about90%when paint4or5ti mes and ever y time the drying time is less than 24h, the relationship of radon mitigation efficiency with the nu mbers ofcoating time accords with the formula p=1－0.6n(n is the coating time).