沈叙言(1997-), 主要从事建筑材料研究, E-mail:
Shen Xuyan (1997-), research interest: building materials, E-mail:
Wang Chong (corresponding author), professor, doctorial supervisor, E-mail:
石灰石粉具有水化活性,能与硅酸盐水泥中的C3A、铝酸盐水泥中的CA、CA2等铝酸盐矿物发生反应,水化产物为水化碳铝酸钙。利用微量热仪法、胶砂强度和X射线衍射(XRD),研究不同比例的石灰石粉铝酸盐水泥复合体系的水化反应,结果表明:石灰石粉会加快铝酸盐水泥的水化进程,水化过程诱导期缩短,放热速率峰值下降;复合体系中石灰石粉占比越高,早期水化反应速率越快,但水化反应放热量越低;相对而言,复合体系中石灰石粉掺量为20%时石灰石粉参与反应程度最高,且掺量为20%时石灰石粉对复合体系强度有显著贡献。随复合体系中石灰石粉比例增加,铝酸盐水泥水化产物越来越不明显;石灰石粉掺量为20%~40%时,水化碳铝酸钙XRD特征峰相对最明显,复合体系中石灰石粉与铝酸盐水泥存在一个最佳的比例范围。研究表明,石灰石粉与铝酸盐水泥间会发生明显的水化反应,石灰石粉与铝酸盐水泥复合有望制得一种新型胶凝材料。
imestone powder (LP) actually has hydration activity and can reacts with aluminate minerals, such as C3A in Portland cement, and CA and CA2 in aluminate cement (AC). The hydration product is calcium carboaluminate hydrate. In this paper, in order to study the hydration reaction, composite systems, which consist of limestone powder and aluminate cement, were analyzed by micro calorimeter, strength test and XRD. The results show that, LP could accelerate the hydration process of the system, and lead to a shorter induction period, an earlier and lower hydration heat peak in the hydration of aluminate cement. The more LP in the composite system, the faster the early hydration, but the lower the hydration heat of the composite system. 20% replacement of limestone powder is the most reactive and contributes significantly to the strength of the composite system. The more limestone powder in the composite system, the less hydration products of the aluminate cement. When the limestone powder content is 20%~40%, the XRD peak of calcium carboaluminate hydrate is relatively obvious. Accordingly, there is a optimal range of AC:LP in the composite system. It is concluded that a significant hydration reaction occurs between limestone powder and aluminate cement. The composite of limestone powder and aluminate cement is expected to produce a new type of cementitious material.
石灰石粉是将以碳酸钙为主要成分的石灰石磨至一定细度得到的粉状材料,其来源广泛,价格低廉,已经被广泛用于水泥混合材和混凝土掺合料中。石灰石粉一般被认为是一种惰性材料,但研究表明,石灰石粉掺入硅酸盐水泥中可以加速硅酸盐水泥的水化[
铝酸盐水泥是以铝酸钙为主要成分的水硬性胶凝材料,其熟料中铝酸钙的含量比硅酸盐水泥更高,有学者将石灰石粉作为铝酸盐水泥的混合材,发现一定掺量的石灰石粉可以抑制铝酸盐水泥后期的倒缩[
由此可见,以碳酸钙为主要成分的石灰石粉可以与铝酸盐矿物发生水化反应,但其水化特性尚未得到系统研究。笔者利用微量热仪法和胶砂强度指标分析了碳酸钙-铝酸盐矿物复合体系的水化放热特性,利用XRD分析水化产物及其结构。
CA-50铝酸盐水泥由郑州登峰熔料有限公司生产,比表面积为501 m2/kg,其化学组成见
铝酸盐水泥的化学组成
Chemical composition of aluminate cement %
CaO | MgO | Fe2O3 | Al2O3 | SiO2 | SO3 |
32.9 | 0.84 | 3.38 | 47.05 | 10.47 | 0.55 |
铝酸盐水泥XRD图谱
XRD pattern of aluminate cement
铝酸盐水泥和石灰石粉的粒径分布
Particle size distribution of aluminate cement and limestone powder
水化热测试采用美国TA公司生产的HEAT Detector of TAM air微量热仪。采用净浆试样,实验配合比如
复合体系净浆配合比
Mix proportion of the paste of the system
样品 | 胶凝材料/% | W/C | |
AC | LP | ||
A0 | 100 | 00 | 0.50 |
A2 | 080 | 20 | 0.50 |
A4 | 60 | 040 | 0.50 |
A6 | 40 | 060 | 0.50 |
A8 | 20 | 080 | 0.50 |
复合体系胶砂试件配合比见
复合体系胶砂试件配合比
Mix proportion of mortar specimens of the system
样品 | AC:LP | 配合比/g | |||
AC | LP | 水 | 砂 | ||
B0 | 1:0 | 450 | 000 | 225 | 1 350 |
B2 | 4:1 | 360 | 090 | 225 | 1 350 |
B4 | 3:2 | 270 | 180 | 225 | 1 350 |
B6 | 2:3 | 180 | 270 | 225 | 1 350 |
B8 | 1:4 | 090 | 360 | 225 | 1 350 |
净浆试块所用配合比如
复合体系的水化速率曲线如
复合体系的水化放热速率
Rate of hydration heat of the composite system
复合体系的水化放热量
Hydration heat of the composite system
将A2、A4、A6和A8复合体系的水化放热量减去等质量的铝酸盐水泥的放热量(以A0放热量为基准),其结果可反映出石灰石粉参与水化反应释放的水化热大小,结果如
复合体系中石灰石参与的反应放热
Hydration heat produced by limestone powder reaction
复合体系胶砂试件抗折强度与抗压强度随复合体系中铝酸盐水泥与石灰石粉质量的比值(AC:LP)变化规律如
复合体系中AC与LP比例对胶砂试件强度影响
Influence of AC:LP on the strength of mortar specimens in composite system
从
从
石灰石在复合体系中虽不具备火山灰反应活性,但可与铝酸盐水泥发生化学反应,因此,也具有化学活性,并且因具有颗粒填充作用,使得石灰石粉具有一定的增强作用。石灰石在复合体系中对强度的影响可参照蒲心诚[
式中:
石灰石粉对复合体系的抗压强度影响分析结果见
石灰石粉对复合体系强度贡献值
Strength contribution of limestone powder in the composite system
从
强度影响研究结果表明,适量石灰石粉对复合体系的强度有积极贡献,本试验条件下复合体系中石灰石粉最佳掺量为20%。
由于A8复合体系的反应太弱,水化产物少,故分析水化产物组成时不考虑A8复合体系。A0、A2、A4和A6复合体系的XRD衍射图谱如
复合体系水化产物XRD图谱
XRD patterns of hydration production of composite system
从
综合分析
石灰石粉中参与反应的主要是碳酸钙,其细度为556 m2/kg,铝酸盐水泥中参与反应的主要来自于CA和CA2矿物熟料,其中还含有较多非活性矿物成分,因此,基于本研究现有结果,若能采用更细的石灰石粉,乃至纯的超细碳酸钙材料,同时,采用活性更高的铝酸盐熟料,优化石灰石粉-铝酸盐复合体系的组成与级配,有望制得一种新的以水化碳铝酸钙为主要水化产物的胶凝材料体系。
1) 石灰石粉会加快复合体系的水化过程,水化过程诱导期缩短。复合体系中石灰石粉占比越高,复合体系的水化放热量越低;复合体系中石灰石粉掺量为20%时石灰石粉参与反应程度最高。
2) 适量石灰石粉对复合体系的强度有积极贡献,本试验条件下复合体系中石灰石粉最佳掺量为20%。
3) 复合体系中存在一个最佳的石灰石粉与铝酸盐水泥比例范围,若能进一步优化石灰石粉-铝酸盐复合体系的组成与级配,有望制得一种以水化碳铝酸钙为主要水化产物的胶凝材料体系。
杨华山, 方坤河, 涂胜金, 等.石灰石粉在水泥基材料中的作用及其机理[J].混凝土, 2006(6):32-35.
YANG H S, FANG K H, TU S J, et al. The effect and its mechanism of calcium carbonate on the cement based materials[J]. Concrete, 2006(6):32-35. (in Chinese)
LAWRENCE P, CYR M, RINGOT E. Mineral admixtures in mortars:Effect of inert materials on short-term hydration[J]. Cement and Concrete Research, 2003, 33(12):1939-1947.
KUZEL H J, PÖLLMANN H. Hydration of C3A in the presence of Ca(OH)2, CaSO4·2H2O and CaCO3[J]. Cement and Concrete Research, 1991, 21(5):885-895.
BURGOS-MONTES O, ALONSO M M, PUERTAS F. Viscosity and water demand of limestone-and fly ash-blended cement pastes in the presence of superplasticisers[J]. Construction and Building Materials, 2013, 48:417-423.
肖佳, 勾成福, 邢昊, 等.石灰石粉对高铝水泥性能的影响[J].建筑材料学报, 2011, 14(3):366-370.
XIAO J, GOU C F, XING H, et al. Effect of ground limestone on performance of high alumina cement[J]. Journal of Building Materials, 2011, 14(3):366-370. (in Chinese)
赵东和.石灰石粉掺量对混凝土性能影响的试验研究[J].混凝土, 2012(6):83-85.
ZHAO D H. Experimental study on the effect of powder dosage to concrete performance[J]. Concrete, 2012(6):83-85. (in Chinese)
肖佳, 许彩云.石灰石粉对水泥混凝土性能影响的研究进展[J].混凝土与水泥制品, 2012(7):75-80.
XIAO J, XU C Y. Research progress on the effect of limestone powder on the performance of cement concrete[J]. China Concrete and Cement Products, 2012(7):75-80. (in Chinese).
BONAVETTI V L, RAHHAL V F, IRASSAR E F. Studies on the carboaluminate formation in limestone filler-blended cements[J]. Cement and Concrete Research, 2001, 31(6):853-859.
THONGSANITGARN P, WONGKEO W, CHAIPANICH A, et al. Heat of hydration of Portland high-calcium fly ash cement incorporating limestone powder:Effect of limestone particle size[J]. Construction and Building Materials, 2014, 66(36):410-417.
VOGLIS N, KAKALI G, CHANIOTAKIS E, et al. Portland-limestone cements:Their properties and hydration compared to those of other composite cements[J]. Cement and Concrete Composites, 2005, 27(2):191-196.
王甲春, 王玉彤, 桂海清, 等.混合材对高铝水泥强度影响的试验研究[J].沈阳建筑工程学院学报(自然科学版), 2002, 18(2):119-122.
WANG J C, WANG Y T, GUI H Q, et al. Experimental study on effect of blending materials on high aluminum cement[J]. Journal of Shenyang Architectural and Civil Engineering Institute, 2002, 18(2):119-122. (in Chinese)
胡曙光, 李悦, 丁庆军.石灰石混合材改善高铝水泥后期强度的研究[J].建筑材料学报, 1998, 1(1):49-53.
HU S G, LI Y, DING Q J. Studies to improve the long term strength of alumina cement by limestone addition[J]. Journal of Building Materials, 1998, 1(1):49-53. (in Chinese)
倪倩, 霍冀川, 牛云辉, 等.矿物掺合料对高铝水泥强度影响的研究[J].混凝土与水泥制品, 2016(11):1-5.
NI Q, HUO J C, NIU Y H, et al. Study on the effect of mineral admixture on the strength of high alumina cement[J]. China Concrete and Cement Products, 2016(11):1-5. (in Chinese).
杨宏章, 孙加林, 章荣会, 等.用碳酸钙微粉改性的高铝水泥及其耐热性能[J].硅酸盐学报, 2006, 34(4):452-457.
YANG H Z, SUN J L, ZHANG R H, et al. High alumina cement modified by limestone powders and its heat-resistant property[J]. Journal of the Chinese Ceramic Society, 2006, 34(4):452-457. (in Chinese)
KAKALI G, TSIVILIS S, AGGELI E, et al. Hydration products of C3A, C3S and Portland cement in the presence of CaCO3[J]. Cement and Concrete Research, 2000, 30(7):1073-1077.
李悦, 胡曙光, 杨德坡, 等.铝酸盐矿物与碳酸钙的水化活性作用[J].河北理工学院学报, 1996, 18(2):54-57.
LI Y, HU S G, YANG D P, et al. Hydration activity reaction between the aluminate minerals and calcium carbonate[J]. Journal of Hebei Institute of Technology, 1996, 18(2):54-57. (in Chinese)
LUZ A P, PANDOLFELLI V C. CaCO3 addition effect on the hydration and mechanical strength evolution of calcium aluminate cement for endodontic applications[J]. Ceramics International, 2012, 38(2):1417-1425.
蒲心诚.高强与高性能混凝土火山灰效应的数值分析[J].混凝土, 1998(6):13-23.
PU X C. Numerical analysis of volcanic ash effect of high strength and high performance concrete[J]. Concrete, 1998(6):13-23. (in Chinese)