亚硝酸钙与富铝矿相协同调控碱矿渣氯离子固化能力研究

Coordinated Control of Chloride Binding Capacity of Alkali Activated Slag by Calcium Nitrite and Aluminum-Rich Mineral Phases

胶凝材料的氯离子固化能力是影响海工混凝土结构服役寿命的关键影响因素。选用亚硝酸钙作为额外钙相,偏高岭土或纳米氧化铝作为额外铝相,探究了钙相和铝相对碱矿渣胶凝材料水化产物、氯离子固化能力和宏观性能的影响。结果表明:亚硝酸钙和铝相的掺入有效促进了胶凝材料的化学反应和氯离子固化能力,胶凝材料的固氯量相较对照组提高了11.5%~34.8%;体系中的m(Ca)/m(Al)值对氯离子固化能力有重要影响,m(Ca)/m(Al)值的降低导致AFm相、C-(A)-S-H凝胶等产物生成量增加;亚硝酸钙的掺量存在极值,若掺量过高会对材料强度造成不利影响,但纳米氧化铝的加入可在一定程度上弥补这一缺陷。

The chloride binding capacity of cementitious materials is a key factor affecting the service life of marine concrete structures.Calcium nitrite was selected as additional calcium phases,and metakaolin or nano alumina was selected as additional aluminum phases.The effects of Ca-Al phases on hydration products,chloride binding capacity and macro performance of alkali activated slag cementitious materials were investigated.The results show that the addition of Ca-Al phases effectively promotes chemical reaction,and improves the chloride binding capacity of alkali activated slag cementitious materials.Compared with control group,the amount of binding chloride increases by 11.5%~34.8%.m(Ca)/m(Al)value in system has an important influence on chloride binding capacity.The decrease of m(Ca)/m(Al)value results in the increase of the content of AFm phases,C-(A)-S-H gels and other products.The content of calcium nitrite has an optimum value.Excessively high content of calcium nitrite negatively affects the strength,but nano alumina compensates for the strength loss.In general,the relative content of Ca-Al phases is important for phase composition and chloride binding capacity of alkali activated slag.