水泥中粉煤灰激发剂的研究

利用HY-ZFS型高分子助磨剂母液和盐类激发剂,对临沂地区的粉煤灰进行激发试验。研究结果表明,HY-ZFS型高分子助磨剂母液对粉煤灰水泥强度的提高具有决定性作用,单独少量掺加盐类激发剂CaCl2和Na2SO4对粉煤灰水泥强度的提高效果很弱,将HY-ZFS母液与各种盐类激发剂复合,对粉煤灰水泥才有激发作用。     

碱激发大掺量粉煤灰胶凝材料的试验研究

将熟石灰粉、氢氧化钾(KOH)等碱激发剂掺入大掺量粉煤灰胶凝材料中以激发粉煤灰的火山灰活性。通过力学性能试验并结合XRD测试分析,探讨了碱激发剂对粉煤灰火山灰活性的激发机理。试验结果表明,碱激发剂能够有效地激发粉煤灰的火山灰活性(尤其是早期活性),复合碱激发剂的作用效果明显优于熟石灰粉单掺的情况。     

有机-无机复合激发剂对粉煤灰活性激发及微观结构研究

对掺加不同激发剂的粉煤灰水泥胶砂的性能进行了试验研究,试验结果表明三乙醇胺对粉煤灰活性的激发在水化早期和后期都有很好的效果,粉煤灰水泥胶砂在各龄期强度较空白组提高幅度最大,无机盐硫酸钠和氯化钠的激发作用也较为明显,碱类激发效果稍差。二元复合激发剂对粉煤灰活性激发效果较最为显著的组合有硫酸钠+三乙醇胺,三元复合激发剂中硫酸钠+氯化钠+三乙醇胺组合作用效果最好。水化产物中3d龄期中存在较多的薄板针状的Ca(OH)2,并随着水化反应的进行逐渐减少。复合激发剂有效促进粉煤灰的火山灰反应,在水化28d的水化产物区域中长针状凝胶产物较少,出现了较多的后期产物的Ⅲ型C-S-H的絮凝状凝胶。     

化学激发粉煤灰-水泥体系的抗压强度性能研究

采用化学途径激发粉煤灰-水泥体系中粉煤灰的活性,通过强度测定研究了几种激发剂单掺、复掺时粉煤灰活性发挥程度,并对激发剂激发效果进行了分析和比较。     

大掺量矿渣-粉煤灰复合水泥活性激发试验研究

论述了在三乙醇胺、硫酸钠、生石灰、生石膏等复合激发的作用下,大掺量活性掺合料（工业废渣掺量70%）的活性激发与强度的关系。研究结果表明：添加复合激发剂对工业废渣进行活化激发可以显著提高大掺量矿渣-粉煤灰水泥的强度,其中三乙醇胺（TEA）、硫酸钠与生石膏复合激发效果最好,并得出了复合激发剂的最佳设计配比。     

烟气脱硫石膏-粉煤灰复合胶凝材料活性激发的量热研究

将燃煤电厂的2大固体废弃物烟气脱硫石膏和粉煤灰变废为宝,研制出绿色环保的免煅烧脱硫石膏-粉煤灰复合胶凝材料.采用八通道热导式等温量热仪,通过研究单掺激发剂:氧化钙、硫酸铝、硅酸钠及三乙醇胺对脱硫石膏-粉煤灰复合胶凝材料的水化放热影响,得出各激发剂单独作用时胶凝材料的活性激发规律.在此基础上,通过正交试验得到脱硫石膏-粉煤灰复合胶凝材料中三种激发剂最佳配比:CaO为10％,Al2(SO4)3为7％,Na2SiO3为0.3％,且影响复合胶凝材料反应放热量的主次顺序为:Al2(SO4)3＞CaO＞Na2SiO3.     

粉煤灰活性复合激发剂的配制及应用研究

粉煤灰混凝土早期强度低，采用碱激发剂熟石灰和硫酸盐激发剂硫酸钠相复合的化学激发方法，配制粉煤灰活性复合激发剂，使粉煤灰混凝土早期强度发展加快，能满足对早期的设计强度要求。     

高掺量粉煤灰-矿渣超细粉建筑胶结料生产研究

以粉煤灰 -矿渣超细粉复合体系为主要材料 ,用普通激发剂激发其活性成分 ,配制成利废率达 80 %以上的建筑胶结料。通过正交试验对激发剂的配比进行优选。试验表明 ,掺入石灰 10 %、石膏 4%、Na2 CO3 0 .5 %和Na2 SO40 .5 %的复合激发剂能使粉煤灰 -矿渣超细粉复合体系的活性成分得到较好的激发。在该复合体系中掺入少量水泥能使该胶结料获得工程使用的强度。粉煤灰 -矿渣超细粉建筑胶结料具有原材料易得、成本低、利废率高等优点     

钢渣粉水化活性的激发技术

将上海宝钢的滚筒钢渣磨细得到钢渣粉,通过水泥净浆实验研究了这种钢渣粉的自硬性及火山灰活性,并分别采用Na_2SO_4、CaCl_2和NaCl为激发剂,以不同的掺量激发钢渣粉的水化活性。结果显示,这种钢渣粉具有一定的自硬性,其早期水化活性较低但具有较高的后期水化活性,Na_2SO_4、CaCl_2和NaCl均对钢渣粉及其与矿粉、或者与矿粉+粉煤灰的复合体系具有活性激发作用,但作用规律及最佳掺量各不相同。3种激发剂的最佳掺量分别为0.9%、0.9%和0.3%,激发剂掺量过高会降低激发效果甚至会产生后期强度倒缩。     

粉煤灰在复合胶凝材料水化过程中的作用机理

分析了粉煤灰在复合胶凝材料水化硬化过程中的作用。探讨了化学激发、物理激发和热激发对于粉煤灰的活性的促进作用以及确定粉煤灰反应程度的方法。粉煤灰的火山灰活性可以用碱性物质或硫酸盐来激发,但是,这种化学激发措施不适合在商品混凝土生产过程中使用。物理激发和热激发是两种简单实用的提高粉煤灰使用效能的技术路线。热激发特别适用于大体积混凝土结构。在复合胶凝材料中,粉煤灰的反应程度很低,不会大量消耗Ca(OH)_2,在水化硬化初期,矿物掺和料主要以物理填充作用参与复合胶凝材料的水化硬化过程;随龄期延长,粉煤灰的火山灰活性作用逐渐明显。     

粉煤灰对碱激发矿渣/粉煤灰体系的作用机理研究

碱激发胶凝材料是以工业固体废弃物为原料制备的一种绿色无机胶凝材料,具有良好的力学性能与耐久性能。粉煤灰因其独特的球体微观结构与其他固废微粉存在本质区别,因此粉煤灰在碱激发胶凝材料体系中的作用机理亟待研究。以矿渣与粉煤灰为原料,利用碱激发剂制备胶凝材料,并对材料进行抗压强度测试,最后采用XRD、FTIR和SEM探究碱激发矿渣/粉煤灰体系的水化反应机理,研究粉煤灰对矿渣/粉煤灰体系的作用机理。结果表明:外掺3%(质量分数)NaOH作为碱激发剂,水固比为0.4时,随粉煤灰掺量减少,抗压强度呈现先上升后下降的趋势;m(矿渣):m(粉煤灰)为4:1时,28 d抗压强度达到峰值(37.1 MPa)。粉煤灰颗粒在不同龄期形成具有不同反应程度与尺寸的嵌入式微观结构,对材料力学性能起到不利影响;但粉煤灰的活化程度随龄期延长逐渐变大,对后期强度发展有持续贡献。碱激发矿渣/粉煤灰体系水化产物中含有Friedel盐、托贝莫来石、钙矾石、C-S-H/C-A-S-H凝胶,以及粉煤灰中残留的α石英相。随粉煤灰掺量增加,托贝莫来石生成量减少,钙矾石向Friedel盐转变,钙矾石生成量减少,Friedel盐生成量增多。     

垃圾焚烧飞灰早期胶凝活性激发研究

从城市生活垃圾焚烧飞灰在水泥混凝土材料领域中的资源化利用角度出发,采用比强度分析方法试验研究了飞灰的胶凝活性,探讨了化学激发剂对飞灰-水泥复合胶凝体系早期强度的活性激发以及相关的机理。结果表明：飞灰早期胶凝活性较低,尤其当掺量高于20％后,表现十分明显。分别掺入1％～3％的CaSO4,KAl（SO4）2,Al2（SO4）3和Na／SiO3的化学激发剂后,浆体的早期抗压强度明显提高,激发效果显著,但随龄期的延长,激发效果减弱。     

Strength and microstructural characteristics of chemically activated fly ash-cement systems

The use of fly ash as a cement replacement material increases the long-term strength and durability of concrete. Despite these great benefits, the use of fly ash is limited due to the low early strength of fly ash concrete. To eliminate this problem, many studies have been conducted on accelerating the pozzolanic properties of fly ash. The study reported below investigated the strength and microstructural characteristics of fly ash-cement systems containing three kinds of activators—Na₂SO₄, K₂SO₄, and triethanolamine—to accelerate the early strength of fly ash mortars. Through the use of thermal gravity analysis, it was demonstrated that the activators not only decreased or maintained the amount of Ca(OH)₂ products, but also increased the production of ettringite at early ages. X-ray diffraction, scanning electron microcopy, and mercury intrusion porosimetry also confirmed that in the early curing stages of fly ash-cement pastes containing activators, large amounts of ettringite were formed, resulting in a reduction in the pore size ranging from 0.01 to 5 μm. The research results support the supposition that the addition of small amounts of activators is a viable solution for increasing the early-age compressive strength of fly ash concrete.     

Influence of new organic alkali activators on microstructure and strength of fly ash geopolymer

The fly ash geopolymer with improved mechanical properties was prepared by a new mixture alkali activator. In this paper, sodium tert-butanol, an organic strong alkali was used as an activator for preparing fly ash geopolymer to improve their mechanical properties. The effect of activator content and type on the macroscopic level of fly ash geopolymer was investigated experimentally by three types of activators: sodium tert-butanol, sodium silicate, and sodium tert-butoxide/sodium silicate mix activator. The microstructure of the fly ash geopolymer was characterized by ATR-FTIR, SEM-EDS, XRD, and Brunauer-Emmett-Teller (BET) physical adsorption method. The results showed that the new mixture alkali activator prepared by 5% sodium tert-butoxide and 10% sodium silicate improved the denseness and integrity of the microstructure of the fly ash geopolymer. Consequently, the mechanical properties of fly ash geopolymer are improved. The microscopic results demonstrated that the C–OH in tert-butanol after the hydrolysis of sodium tert-butoxide and Si–OH in the geopolymer can form C–O–Si bonds, forming a more complex three-dimensional network structure. This paper reveals the enhancement mechanism of organic alkali as activators for preparing fly ash geopolymer, and provides support for the subsequent development of organic strong alkali activators.     

Catalytic effects of inorganic compounds on the development of surface areas of fly ash carbon during steam activation

This study was to investigate the catalytic effect of inorganic compositions present in fly ash carbons, high-unburned-carbon content fly ashes from coal-fired power plants, on the development of surface area during steam activation. Through this work, the relationships between the concentrations of alkali metals (Na and K) and a mixture of metals, Na-K-Ca and Na-K-Fe, in fly ash carbon and the surface areas of the produced activated carbon were studied.Six fly ash carbons were selected as feedstocks for activated carbon. SEM/EDS studies showed that there are two groups of inorganic particles present in fly ash carbons, in terms of the way they are associated with carbon particles: inorganic particles that exist as free single particles, and inorganic particles that are combined with the carbon particles. A series of froth flotation tests was conducted to separate the individual inorganic particles from the fly ash carbons. The concentration of the inorganic particles was analyzed using ICP-AES before and after froth flotation separation. Studies showed that the Na-K, Na-K-Ca, and Na-K-Fe which are combined with carbon particles had catalytic effects on the development of the surface areas of activated carbons. The higher the concentration of these catalytic particles, the more significant effects they had on the development of the surface areas with increasing carbon burn-off levels.     

不同“增钙”情况下低质粉煤灰活化技术研究

本文总结了国内外粉煤灰活化技术研究现状 ,对两种Ⅲ级粉煤灰活化技术进行了较系统的研究。采用石灰膏与磨细熟石灰粉对粉煤灰水泥砂浆中的粉煤灰进行“增钙” ,在此基础上掺入各种激发剂与其不同掺量来激发粉煤灰的活性。通过测试砂浆试样的不同龄期力学强度和 pH值 ,对粉煤灰活性激发效果和粉煤灰活化机理进行了分析。试验结果表明 ,采用磨细熟石灰粉对粉煤灰进行“增钙”更为有效。     

粉煤灰及锂盐对水泥砂浆碱集料反应复合抑制效果的探讨

通过砂浆棒快速法考察掺入粉煤灰和锂盐对砂浆棒膨胀率的影响,研究向水泥砂浆中同时添加粉煤灰和锂盐对碱集料反应（AAR）的抑制效果。结果表明,适量掺人粉煤灰和锂盐可以较好的起到对碱集料反应的抑制作用。     

Influence of steam curing on the compressive strength of concrete containing supplementary cementing materials

Heat treatment is widely used to accelerate the strength-gaining rate of concrete. In general, the ultimate strengths of the heated-treated concrete are lower than those of the standard cured specimens. When ultrafine fly ash (UFA) is included in concrete, the pozzolanic reaction is accelerated through the heat treatment. Sometimes, various chemical activators were used to activate the reactivity of fly ash. In the current study, UFA and slag were used as a replacement for cement, steam curing and chemical activators were used to accelerate hydration of cement and fly ash, and then compared with moist curing. This paper presents the influence of steam curing on the compressive strength of concrete containing UFA with or without slag. The experimental results indicated that the concrete containing UFA has low early strength after 13-h steam curing and that the difference between the 28-day compressive strength of concrete through 13-h steam curing and that of moist-cured concrete is large, but the concrete with UFA and CaSO₄ or Ca(OH)₂ has a high early strength, thus, the reactivity of fly ash must be accelerated. Concrete containing UFA and ground slag was prepared, whose compressive strengths were improved.     

粉煤灰基地质聚合物的研究进展

论述了粉煤灰基地质聚合物的特殊网状结构,激发剂的类型和配比,养护制度和应用方面的国内外研究情况,并对粉煤灰基地质聚合物的发展进行了展望.