限定碱性速凝剂使用量的总说明.pdfVIP

1 限定碱性速凝剂的使用量 限定NaO碱当量的总量管制 2 台有化学公司总经理 廖明辉 地址：高雄市三民区民族一路39巷6之6号7楼 (4、1)、美国ACI221.1R-98(Reapproved2008),3.1.1-3有相关规定!! ACI 221.1R-98 State-of-the-Art Report on Alkali-AggregateReactivityReportedbyACICommittee221 CHAPTER 3—ALKALI-SILICA REACTIVITY MECHANISMS 3. Because the relevant issue with respect to ASR is the concentration of hydroxyl ion (pH) in the concrete, the cement factor playsan importantrole that isdisregarded in thetraditionalconsideration of cement-alkalicontent (Na2Oe).Various limits on the mass of alkali-per-unit volume of concrete have been suggested as a more appropriate method to prevent damaging ASR.A maximum value of 3 kg/m3 is often cited as sufficient to prevent damage in the presence of reactive aggregates (Concrete Society Working Party 1987 ;and Portland Cement Association 1994). The limit includes alkalies contributedfrompozzolansor slag,aswellasthecement. The Canadian Standards Association (CSA A23.1) places a limitof3kg/m3onthealkalicontributionfrom thecement alone. Ozol (1990) reported on field occurrences of ASR where chemical analyses suggested concrete alkali contents of 1.8 kg/m3, and Ozol and Dusenberry (1992) reported ASR in concrete with an alkali content of 2.3 kg/m3. Based on laboratory tests, Johnston (1986) suggests that concrete alkali contents less than 0.05 percent (1.2 kg/m3, for concrete with a density of 2320 kg/m3) were clearly safe, whereas alkali contents greater than 0.10 percent (2.3 kg/m3) would clearly causeproblemswhenusedwithreactiveaggregate. 2 (4、2)、大陆人民交通出版社:(隧道与地铁施工专题精进丛书) 隧道及 地下工程喷混