西安建筑科技大学学报(自然科学版)

氯离子的固化能力影响到碱激发偏高岭土-矿渣代替水泥用于混凝土结构的耐久性.为此,研究碱激发偏高岭土-矿渣硬化浆体(Alkali activated metakaolin-slag, AAMS)固化氯离子的能力,通过等温吸附平衡法和X射线衍射(XRD)方法考察了矿渣掺量、激发剂模数和激发剂浓度等因素的影响.研究结果表明:AAMS对氯离子的固化能力主要归因于C/N-A-S-H和C-S-H凝胶对氯离子的物理吸附; 碱激发偏高岭土的氯离子固化能力较水泥净浆(PC)差,但矿渣掺入后可以提高碱激发偏高岭土对氯离子的固化能力; Langmuir等温线对AAMS固化后的游离氯离子与结合氯离子之间的关系具有更好地拟合效果.AAMS对NaCl溶液中氯离子的固化效果受NaCl溶液浓度的影响,对高浓度(>1.0 mol/L)NaCl溶液的吸附更加显著.AAMS对氯离子的固化能力随激发剂模数和激发剂浓度的减小而增大,尤以激发剂浓度的影响为最,且随矿渣掺量的增加,二者对AAMS固化氯离子的影响越显著.

The ability to bind chloride ions is related to the durability of alkali activated metakaolin-slag blends in place of cement for concrete structures. In this work, the effects of slag dosage, activator modulus, concentration of activator and other factors on the ability of the alkali activated metakaolin-slag blends(AAMS)to bind chloride ions were studied by isothermal adsorption equilibrium method and X-ray diffraction(XRD)method. The results show that the binding ability of AAMS for chloride ions is mainly attributed to the physical adsorption of chloride ions by C/N-A-S-H and C-S-H gels. The chloride binding ability of alkali-activated metakaolin is poorer than that of cement paste(PC), but slag incorporation can improve the binding ability of alkali-activated metakaolin for chloride ions. Langmuir isotherm has a better fitting effect on the relationship between free chloride ions and bound chloride ions after AAMS binding. The binding effect of AAMS is influenced by the concentration of NaCl solution, which is more significant for high concentration(>1.0 mol/L)NaCl solution. The binding ability of AAMS on chloride ions increases with the decrease of activator modulus and activator concentration, especially the effect of activator concentration is the most important, and with the increase of slag dosing, the more significant the effect of both on AAMS binding chloride ions.

引言
1 试验材料及方法
2 试验结果与分析
3 结论

表1 胶凝材料的化学成分/%<br/>Tab.1 Chemical composition of binding materials /%

表1 胶凝材料的化学成分/%
Tab.1 Chemical composition of binding materials /%

表2 试件配合比<br/>Tab.2 Mix proportion of specimens

表2 试件配合比
Tab.2 Mix proportion of specimens

图1 未经过氧化除杂的待测液的电位滴定结果<br/>Fig.1 Potential titration results of the solution to be tested without oxidation and impurity removal

图1 未经过氧化除杂的待测液的电位滴定结果
Fig.1 Potential titration results of the solution to be tested without oxidation and impurity removal

图2 氧化除杂后的待测液的电位滴定结果<br/>Fig.2 Potentiometric titration results of the solution to be tested after oxidation and impurity removal

图2 氧化除杂后的待测液的电位滴定结果
Fig.2 Potentiometric titration results of the solution to be tested after oxidation and impurity removal

图3 吸附平衡与时间的关系<br/>Fig.3 Relation between adsorption equilibrium and time

图3 吸附平衡与时间的关系
Fig.3 Relation between adsorption equilibrium and time

图4 PC净浆的Cl-等温吸附曲线比较<br/>Fig.4 Comparison of chloride ion binding isothermal adsorption curves of PC slurry

图4 PC净浆的Cl-等温吸附曲线比较
Fig.4 Comparison of chloride ion binding isothermal adsorption curves of PC slurry

图5 PC净浆在1.0 M氯化钠溶液吸附前后的XRD图谱<br/>Fig.5 XRD patterns of PC slurry before and after adsorption on 1.0 M NaCl solution

图5 PC净浆在1.0 M氯化钠溶液吸附前后的XRD图谱
Fig.5 XRD patterns of PC slurry before and after adsorption on 1.0 M NaCl solution

表3 PC和AAMS的Linear、Freundlich和Langmuir 等温线的拟合参数<br/>Tab.3 Fitted parameters for Langmuir、Freundlich and Langmuir isotherms for PC and AAMS

表3 PC和AAMS的Linear、Freundlich和Langmuir 等温线的拟合参数
Tab.3 Fitted parameters for Langmuir、Freundlich and Langmuir isotherms for PC and AAMS

图6 AAMS和PC净浆的Cl-等温吸附曲线<br/>Fig.6 Chloride ion binding isotherms adsorption curves of AAMS and PC slurry

图6 AAMS和PC净浆的Cl-等温吸附曲线
Fig.6 Chloride ion binding isotherms adsorption curves of AAMS and PC slurry

图7 AAMS在氯化钠溶液中吸附前后的XRD图谱<br/>Fig.7 XRD patterns of AAMS before and after adsorption in NaCl solution

图7 AAMS在氯化钠溶液中吸附前后的XRD图谱
Fig.7 XRD patterns of AAMS before and after adsorption in NaCl solution

图8 矿渣掺量为不同模数的AAMS的Cl-等温吸附曲线<br/>Fig.8 Chloride ion binding isothermal adsorption curves for different modulus of AAMS with slag dosage

图8 矿渣掺量为不同模数的AAMS的Cl-等温吸附曲线
Fig.8 Chloride ion binding isothermal adsorption curves for different modulus of AAMS with slag dosage

图9 矿渣掺量为不同模数的AAMS在氯化钠溶液中吸附前后的XRD图谱<br/>Fig.9 XRD patterns before and after adsorption of different modulus of AAMS in NaCl solution with slag dosage

图9 矿渣掺量为不同模数的AAMS在氯化钠溶液中吸附前后的XRD图谱
Fig.9 XRD patterns before and after adsorption of different modulus of AAMS in NaCl solution with slag dosage

图10 矿渣掺量为不同浓度的AAMS的Cl-等温吸附曲线<br/>Fig.10 Chloride ion binding isothermal adsorption curves for different concentrations of AAMS with slag dosage

图10 矿渣掺量为不同浓度的AAMS的Cl-等温吸附曲线
Fig.10 Chloride ion binding isothermal adsorption curves for different concentrations of AAMS with slag dosage

图11 矿渣掺量为不同浓度的AAMS在氯化钠溶液中吸附前后的XRD图谱<br/>Fig.11 XRD patterns before and after adsorption of different concentration of AAMS in NaCl solution with slag dosage

图11 矿渣掺量为不同浓度的AAMS在氯化钠溶液中吸附前后的XRD图谱
Fig.11 XRD patterns before and after adsorption of different concentration of AAMS in NaCl solution with slag dosage

[1]Martín-Pérez B, ZIBARA H, HOOTON R D, et al. A study of the effect of chloride binding on service life predictions[J]. Cement and Concrete Research. 2000, 30(8): 1215-1223.
[2]HIRAO H, YAMADA K, TAKAHASHI H, et al. Chloride binding of cement estimated by binding isotherms of hydrates[J]. Journal of advanced concrete technology. 2005, 3(1): 77-84.
[3]YE H, JIN X, CHEN W, et al. Prediction of chloride binding isotherms for blended cements[J]. Computers & Concrete. 2016.
[4]BALONIS M, LOTHENBACH B, Le Saout G, et al. Impact of chloride on the mineralogy of hydrated Portland cement systems[J]. Cement and Concrete Research. 2010, 40(7): 1009-1022.
[5]DAVIDOVITS J. Geopolymers: Inorganic polymeric new materials[J]. Thermal Analysis, 1991, 37(8): 1633-1656.
[6]PALOMO A, GRUTZECK M W, BLANCO M T, et al. Alkali-activated fly ashes: A cement for the future[J]. Cement and concrete research. 1999, 29(8): 1323-1329.
[7]ISMAIL I, BERNAl S A, PROVIS J L, et al. Influence of fly ash on the water and chloride permeability of alkali-activated slag mortars and concretes[J]. Construction and Building Materials. 2013, 48: 1187-1201.
[8]LEE N K, LEE H K. Influence of the slag content on the chloride and sulfuric acid resistances of alkali-activated fly ash/slag paste[J]. Cement and Concrete Composites. 2016, 72: 168-179.
[9]BROUGH A R, HOLLOWAY M, SYKES J, et al. Sodium silicate-based alkali-activated slag mortars: Part II. The retarding effect of additions of sodium chloride or malic acid[J]. Cement and Concrete Research. 2000, 30(9): 1375-1379.
[10]BABAEE M, CASTEL A. Chloride diffusivity, chloride threshold, and corrosion initiation in reinforced alkali-activated mortars: Role of calcium, alkali, and silicate content[J]. Cement and Concrete Research. 2018, 111: 56-71.
[11]KE X, BERNAL S A, HUSSEIN O H, et al. Chloride binding and mobility in sodium carbonate-activated slag pastes and mortars[J]. Materials and Structures. 2017, 50(6):252.
[12]KE X, BERNAL S A, PROVIS J L. Uptake of chloride and carbonate by Mg-Al and Ca-Al layered double hydroxides in simulated pore solutions of alkali-activated slag cement[J]. Cement and Concrete Research. 2017, 100: 1-13.
[13]FLOREA M V A, BROUWERS H J H. Chloride binding related to hydration products[J]. Cement and Concrete Research. 2012, 42(2): 282-290.
[14]T Luping, NILSSON L O. Chloride binding capacity and binding isotherms of OPC pastes and mortars[J]. Cement and Concrete Research, 1993, 23(2):247-253.
[15]ZIBARA H. Binding of external chlorides by cement pastes, Department of Building materials[D]. Toronto Canada:University of Toronto, 2001.
[16]YANG T, YAO X, ZHANG Z H. Quantification of chloride diffusion in fly ash-slag-based geopolymers by X-ray fluorescence(XRF)[J]. Construction and Building Materials, 2014, 69(10):109-115.
[17]YE H, HUANG L, CHEN Z. Influence of activator composition on the chloride binding capacity of alkali-activated slag[J]. Cement and Concrete Composites. 2019, 104: 103368.
[18]ZHANG J, SHI C J, ZHANG Z H. Chloride binding of alkali-activated slag/fly ash cements[J]. Construction and Building Materials. 2019, 226: 21-31.
[19]彭晖,李一聪,罗东,等. 碱激发偏高岭土/矿渣符合凝胶体系反应水平及影响因素分析[J]. 建筑材料学报, 2020,23(6):1390-1397.
[20]罗睿,蔡跃波,王昌义. 磨细矿渣净浆和砂浆结合外渗氯离子的性能[J]. 建筑材料学报, 2001,4(2):148-153.
[21]NEVILLE A M. Properties of Concrete, fourth and final edition[B]. London: Longman Group Limited, 1996.
[22]NT Build.Concrete, mortars and cement-based repair materials: chloride migration coefficient from non-steady-state migration experiments[S]. Amsterdam: Elsevier,1999.
[23]C Astm. Standard test method for electrical indication of concrete's ability to resist chloride ion penetration:ASTM C1202[S]. Londom: Bsi, 2010.
[24]SONG S, JENNINGS H M. Pore solution chemistry of alkali-activated ground granulated blast-furnace slag[J]. Cement and Concrete Research, 1999,29(2):159-170.
[25]LLOYD R R, PROVIS J L, van Deventer J S J. Pore solution composition and alkali diffusion in inorganic polymer cement[J]. Cement and Concrete Research. 2010, 40(9): 1386-1392.
[26]THEISSING E M, Hest-Wardenier P V. The combining of sodium chloride and calcium chloride by a number of different hardened cement pastes[J]. Cement and Concrete Research,1978,8(6):683-691.
[27]ARYA C, BUENFELD N R, NEWMAN J B. Factors influencing chloride-binding in concrete[J]. Cement and Concrete Research,1990,20(2)291-300.
[28]CHENG S, SHUI Z, SUN T, et al. Effects of sulfate and magnesium ion on the chloride transportation behavior and binding capacity of Portland cement mortar[J]. Construction and Building Materials. 2019, 204: 265-275.
[29]PAPADAKIS V G, Danish Technological Inst. T D. Effect of supplementary cementing materials on concrete resistance against carbonation and chloride ingress[J]. Cement and Concrete research. 2000, 30(2): 291-299.
[30]SHEHATA M H, THOMAS M D A, Alkali release characteristics of blended cements[J].Cement and Concrete research. 2006,36(6)1166-1175.
[31]FU C, YE H, ZHU K, et al. Alkali cation effects on chloride binding of alkali-activated fly ash and metakaolin geopolymers[J]. Cement and Concrete Composites. 2020, 114: 103721.
[32]SHEHATA M H, THOMAS M D A. Alkali release characteristics of blended cements[J]. Cement and Concrete Research. 2006, 36(6): 1166-1175.
[33]郭晓潞,施惠生,夏明. 不同钙源对地聚合物反应机制的影响研究[J]. 材料研究学报. 2016, 30(5): 348-354.
[34]余红发,翁智财,孙伟,等. 矿渣掺量对混凝土氯离子结合能力的影响[J]. 硅酸盐学报. 2007(6): 801-806.
[35]CRIADO M, APERADOR W, SOBRADOS I. Microstructural and mechanical properties of alkali activated colombian raw materials[J]. Materials. 2016, 9(3): 158.
[36]Y Jun, SYoon, J Oh. A Comparison study for chloride-binding capacity between alkali-activated fly ash and slag in the use of seawater[J]. Applied Sciences. 2017, 7(10): 971.
[37]ZHANG J, SHI C, ZHANG Z. Carbonation induced phase evolution in alkali-activated slag/fly ash cements: The effect of silicate modulus of activators[J]. Construction and Building Materials. 2019, 223: 566-582.
[38]SANDBERG P, Studies of chloride binding in concrete exposed in a marine environment[J]. Cement and Concrete Research. 1999,29(4):473-477.
[39]WANG S D, SCRIVENER K L. Hydration products of alkali activated slag cement[J]. Cement and Concrete Research.1995, 25(3):561-571.
[40]BERNAL S A, PROVIS J L, WALKLEY B, et al. Gel nanostructure in alkali-activated binders based on slag and fly ash, and effects of accelerated carbonation[J]. Cement and Concrete Research.2013, 53(6):127-144.

备注

引言

1 试验材料及方法

2 试验结果与分析

3 结论

期刊信息