超细矿渣粉和偏高岭土对硫铝酸盐水泥水化和强度的影响

掺入矿物掺合料是改善硫铝酸盐水泥(CSA)混凝土凝结硬化性能和降低生产成本的主要技术途径之一。研究了水胶比为0.4时,单掺超细矿渣粉(UFS)、偏高岭土(MK)与复掺超细矿渣粉、偏高岭土对硫铝酸盐水泥凝结时间、流动度、电阻率、抗压强度的影响,并对其1 d、28 d龄期时的水化产物进行XRD半定量分析。结果表明,单掺和复掺缩短了水泥浆体的凝结时间,但单掺偏高岭土时的缩短效果更明显,且水泥浆体的流动度随着超细矿渣粉和偏高岭土掺量的增加而减小。掺入超细矿渣粉、偏高岭土缩短了水泥浆体电阻率变化速率曲线峰值出现的时间,峰值大小与掺量成递减关系。当掺量从0%(质量分数,下同)增大到20%时,单掺超细矿渣粉试样的28 d抗压强度减小了24.7%,单掺偏高岭土试样的28 d抗压强度减小了17.7%,两者复掺试样的28 d抗压强度减小了17.3%。超细矿渣粉和偏高岭土对水泥水化产物没有明显影响,但促进了硅酸二钙(β-C₂S)的早期水化。     

Effect of blended inorganic salts containing negative hydration ions on hydration and properties of alkali-activated slag cement

Water glass (WG) is generally considered to be the most effective activator to prepare alkali-activated slag (AAS) cement in terms of strength and durability. However, the rapid setting and hardening of WG activated slag results in rapid loss of fluidity of AAS concrete mixture, which limits its engineering application. In the paper, the effect of blended inorganic salts containing negative hydration ions on the fluidity, setting time and mechanical strength of AAS cement was studied. The hydration process and hydration products were used to explore the action mechanism. Ba(NO₃)₂ greatly delayed the hydration of AAS cement. The four inorganic salts (KCl, KNO₃, KBr and NaCl) blended with a small amount of Ba(NO₃)₂ can improve both the initial fluidity and fluidity retention, and a wide setting time range can be obtained to meet engineering requirements. The compressive strength decreased with the increase of inorganic salts. The incorporation of inorganic salt did not change the composition of the main hydration products. Considering the fluidity required by construction, mechanical properties and the durability of structure, it is recommended to add 4%–5% KBr or KNO₃ blended with no more than 0.2% Ba(NO₃)₂ into AAS cement.     

煤矸石-矿渣-水泥体系的水化进程及其性能研究

采用选择性溶解法和非线性拟合法分别测量了煤矸石-矿渣-水泥三元体系中三种原材料（煤矸石,矿渣,水泥）的水化进程,并对含有不同掺量矿物掺合料的复合水泥浆体干燥收缩及抗压强度进行了测量和分析。结果表明：当复合水泥浆体中含有5％煤矸石,25％矿渣时,复合材料的干燥收缩较小,抗压强度较大。     

矿渣粉颗粒群参数对矿渣活性和混合水泥性能的影响

以混合材料的填充效应和微集料效应为基础,测试了不同颗粒分布矿渣粉制备的水泥的物理性能,研究了矿渣粉颗粒群参数对水泥使用性能和混合水泥抗压强度比的影响。结果表明,矿渣粉颗粒分布宽、粗大化有利于混合水泥使用性能的提高;同时,颗粒堆积密度也影响混合水泥抗压强度比的高低,但主要对早期作用明显,而后期的抗压强度比则与矿渣粉的比表面积直接相关。     

Sorptivity and strength of air-cured and water-cured PC-PFA-MK concrete and the influence of binder composition on carbonation depth

The paper reports the influence of the composition of Portland cement-pulverised fuel ash-metakaolin (PC-PFA-MK) binders on sorptivity and strength development of PC-PFA-MK concrete cured both in air and in water and on carbonation depth, and relates this to measured changes in sorptivity of the concrete. Concrete mixtures covering four different total cement replacement levels (10%, 20%, 30% and 40%) for PC-PFA-MK concrete with various MK/PFA proportions, water and air cured for up to 18 months, were investigated. The change in compressive strength and sorptivity with age at all cement replacement levels under both water and air curing are compared with those of the control PC concrete. The results presented in this paper form part of an investigation into the optimisation of a ternary blended cementitious system based on ordinary PC, PFA and MK for the development of high-performance concrete.     

高分散性丁苯胶乳的制备及其对水泥的改性

添加传统丁苯胶乳进行改性,大大提高了水泥的力学性能,但是改性后的水泥材料流动性能差,抗压性能损失较多。为了提高添加丁苯胶乳后水泥的流动性及降低抗压性能损失,本文对丁苯胶乳进行改性,以苯乙烯与聚丁二烯作为核层、带有苯环的对苯乙烯磺酸钠作为壳层,制备出核壳型丁苯（SSBR）胶乳。把新合成的SSBR胶乳加入水泥后,对水泥力学性能进行表征,由于SSBR胶乳中与磺酸根相连的是苯环刚性链,空间位阻效应明显,添加8% SSBR胶乳水泥浆的流变指数增大为0.898,分子链强度大,水泥石的7天抗压强度损失量为2.31%,损失不明显,同时抗折强度提高17%。对SSBR胶乳改性水泥石材料力学性能的作用机理进行探究,结果表明,SSBR胶乳填充作用明显,吸附作用较强,增大水泥浆流动性能,且胶乳粒子可以与Ca²⁺络合,形成三维网状空间立体结构,从而达到增强水泥石力学性能强度,提高水泥石韧性的目的。     

锂渣和钢渣对水泥浆体力学性能与微观结构的影响

利用锂渣粉和钢渣粉替代部分P·O 42.5水泥制备了复合水泥净浆试样。通过SEM、XRD、FT-IR等测试方法分析了二者对试样的影响及作用机制。结果表明,锂渣替代部分水泥会降低浆体的流动性,钢渣替代部分水泥有利于提高浆体流动性。锂渣具有促凝效果,而钢渣在浆体中可发挥缓凝作用。锂渣、钢渣复合掺入时可调控浆体的流动性和凝结时间。锂渣对浆体力学性能的提高相比钢渣具有更明显的优势,当水胶比为0.4时,掺入20%(质量分数)锂渣的试样28 d抗压强度可达62.3 MPa,相比空白样可提高23%左右。SEM结果显示掺20%锂渣可使试样28 d微观结构更致密。XRD结果显示试样的水化产物主要为C-S-H凝胶和Ca(OH)₂。FT-IR结果显示Si—O键峰位发生了一定的红移,H—O—H键发生了蓝移。     

磨细矿渣对高性能混凝土性能的影响1掺加磨细矿渣的砂浆试验

研究了矿渣的细度、掺量对水泥砂浆的强度和流动性的影响。结果表明：矿渣细度较小时,抗压强度随着掺量的增加而下降。当细度变大,强度随着掺量增加而下降的趋势变缓。细度超过一定值后,强度随着掺量的增加呈现上升趋势。同时,细度、掺量对早期（３ ｄ、７ ｄ）强度和后期（２８ ｄ）强度的影响也有差别。细度低于 ８００ ｍ ２ ／ｋｇ 的矿渣对砂浆的流动性影响不大,但细度高于 ８００ ｍ ２ ／ｋｇ的超细矿渣能够显著降低用水量。试验结果为研究矿渣在高性能混凝土中的应用提供了依据。     

Multi-scale characteristics of magnesium potassium phosphate cement modified by metakaolin

Workability and early-ages mechanical properties are important indicators of magnesium potassium phosphate cement (MKPC) as a repair material. The effect of metakaolin (MK) on the setting time, fluidity and early-ages strength of MKPC paste was studied, and its influence mechanism was analyzed through pore structure, microstructure and nanomechanical properties. The results show that 10% and 20% of MK prolong the setting time of MKPC paste, but excessive MK shortens the setting time of MKPC paste. Meanwhile, incorporating MK reduces the fluidity of MKPC paste, and the early-ages strength of MKPC specimens increases when the substitution ratio of MK is 10%. When 10% of MK is incorporated to the MKPC paste, the 30-d shrinkage of the sample is only 69% of the control group. Meanwhile, a proper amount of MK can improve the pore structure of the MKPC specimen and make its microstructure denser by generating amorphous aluminosilicate phosphate gel. It is observed from the nano-scale characteristics that incorporating 10% MK can reduce the content of pore phase and unreacted MgO phase, and increase the volume fraction of hydration products.     

风冷高炉渣与水淬高炉渣的水化性能研究

分析了风冷高炉渣和水淬高炉渣的矿物组成和玻璃体含量。在此基础上,对比研究了风冷高炉渣复合体系水泥和水淬高炉渣复合体系水泥的净浆强度、水化产物的矿物相组成和微观形貌。结果表明,风冷高炉渣的主要组成为玻璃体和α'L-C2S,玻璃体含量为83.34%;水淬高炉渣的主要组成为玻璃体,玻璃体含量为96.79%。水化28d时,风冷高炉渣复合体系水泥与水淬高炉渣复合体系水泥相比,净浆抗压强度接近,水化产物的主要矿物相组成无明显差别。     

气淬钢渣作水泥混合材的初步研究

研究了气淬钢渣的粉磨特性、掺气淬钢渣水泥的水化反应机理和物理性能。结果表明,气淬钢渣的易磨性明显好于普通钢渣;在掺量达到40%时,掺气淬钢渣的水泥7d抗折强度明显高于掺普通钢渣的水泥。     

混合材料微粉对水泥砂浆性能的影响

用不同掺量的矿渣粉及粉煤灰对水泥砂浆流动性和抗压强度进行了试验研究。结果表明：矿渣粉和粉煤灰都可以提高砂浆的流动性,它们对水泥砂浆的流动度及抗压强度的影响与水泥品种及砂浆配合比有关。     

纳米SiO2对钢渣水泥基胶凝材料的影响

钢渣和水泥具有相似的矿物组成,可以作为一种潜在的胶凝材料,然而钢渣掺量较高时并不利于混凝土早期性能的发展。以钢渣质量分数为30%的钢渣水泥基胶凝材料为研究对象,探讨纳米SiO₂对其早期性能的影响。主要通过测量流动度、凝结时间和抗压强度评估物理力学性能,并利用微量热分析、X射线衍射(XRD)、差热分析(DSC-TG)等方法对掺有纳米SiO₂的钢渣水泥基胶凝材料的水化过程和水化产物进行分析。结果表明,当纳米SiO₂掺入的质量分数为3%时,纳米SiO₂可充分发挥火山灰活性,消耗大量Ca(OH)₂,同时由于纳米SiO₂颗粒的结晶成核作用和微集料填充作用,促进了钢渣和水泥的水化,水化初期的放热速率有所提高,从而提高钢渣水泥基胶凝材料的力学性能,28 d的抗压强度提高了14.0%。     

砂岩石质文物灌浆材料的成分设计及多场景应用研究

为了制备出性能可调且满足多场景应用的砂岩石质文物灌浆材料,采用四角配料法,以水硬性石灰(NHL2)、硫铝酸盐水泥(SAC)、偏高岭土(MK)和水性环氧树脂(WER)为原料,制备出不同配方的灌浆材料,并对其力学性能、凝结时间、流动性、粘接强度等进行测试分析。结果表明,NHL2和MK含量较高的灌浆材料,抗压强度和粘接强度较低,适用于修复壁画或镶嵌图案。SAC和WER含量较高的灌浆材料,抗压强度和粘接强度较高,适用于修复断崖、悬岩型砂岩石质文物。WER和MK含量较高的灌浆材料,韧性和变形能力良好,适用于修复易受外界应力的砂岩石质文物。     

矿粉掺量对废弃超细砂制备砂混凝土密度及强度影响研究

以航道整治废弃超细砂为主要原料,通过振动成型制备砂混凝土(Sand Concrete).首先通过干拌振捣密实计算干拌物密度的方法研究矿粉掺量对砂混凝土干拌物密度的影响,然后以试件7 d、14 d和28 d抗压强度、劈裂抗拉强度和浸水抗压强度为控制标准,研究矿粉掺量对砂混凝土性能的影响,最后通过XRD对砂混凝土试件进行分析.试验结果表明:在水胶比为0.38,减水剂掺量为0.5%情况下,砂混凝土最佳配合比为废弃超细砂75.3%、水泥16.5%、矿粉8.2%.采用最佳配合比所制砂混凝土28 d抗压强度、劈裂抗拉强度和浸水抗压强度均达到最优, XRD分析表明所制砂混凝土含有大量水化硅酸钙(C-S-H)和钙矾石等水化产物.研究为航道整治废弃超细砂的开发利用提供一种技术途径,对于废弃超细砂资源丰富而普通混凝土砂石材料匮乏的地区具有显著的经济价值和广阔的应用前景.     

偏高岭土、矿渣和赤泥对高性能混合水泥性能影响的研究

通过用硅酸盐水泥、偏高岭土等混合材、膨胀剂及减水剂等制备混合水泥的研究发现：偏高岭土和赤泥的加入使水泥的凝结时间缩短,矿渣的加入延长了水泥的凝结时间;偏高岭土和矿渣对水泥的胶砂流动性影响较小,赤泥的加入使得水泥胶砂流动性显著降低;适量偏高岭土的加入对水泥的3d和28d强度均有增强作用,适量矿渣的加入使水泥抗折强度降低,抗压强度增大;少量的赤泥对水泥强度特别是早期强度有一定的增强作用,但掺量超过20％后水泥强度迅速降低;偏高岭土对水泥微膨胀的产生有促进作用,矿渣和赤泥对水泥微膨胀有抑制作用。用80％～90％的硅酸盐水泥、10％～20％的偏高岭土以及少量的膨胀剂和减水剂能够制备出具有较优流动性、较高的强度以及微膨胀的高性能混合水泥。     

超细矿渣在水泥砂浆中的应用研究

在普通硅酸盐水泥砂浆中加入济钢产超细矿渣,研究不同掺量的超细矿渣对水泥浆体凝结时间及胶砂流动度、强度的影响.实验结果表明:随着掺量的提高,水泥浆体的初凝时间延长,终凝时间缩短;胶砂流动度随超细矿渣掺量的增大而减小;随超细矿渣掺量的增大,水泥胶砂的3d和28 d强度提高,当质量分数掺量为30％时,水泥砂浆28 d的抗折、抗压强度达到最大,分别达到9.65 MPa和68.44 MPa.     

Chloride ingress and strength loss in concrete with different PC-PFA-MK binder compositions exposed to synthetic seawater

The paper reports the influence of the composition of Portland cement (PC)-pulverised fuel ash (PFA)-metakaolin (MK) binders on chloride ingress and strength retardation of PC-PFA-MK concrete exposed to synthetic seawater. PC-PFA-MK concrete covering four different total cement replacement levels (10%, 20%, 30% and 40%) and with various MK:PFA proportions was exposed to synthetic seawater for up to 1.5 years. The chloride concentration-penetration depth profiles and change in compressive strength of the concrete for a range of binder compositions and at various exposure times are compared with those of the control PC concrete. It is established that blending the binders in PC concrete and PC-PFA concrete with MK produces concrete with a reduced strength deterioration factor (SDF) and good resistance to chloride penetration when exposed to seawater. The results presented in this paper form part of an investigation into the performance of concrete incorporating both PFA and MK in the binder to produce high performance concrete.     

利用电炉氧化钢渣制备混凝土矿物掺合料的研究

研究了磨细电炉氧化钢渣对水泥标准稠度需水量、水泥净浆流动度以及混凝土抗压强度、抗渗性、抗冻性、抗碳化等性能指标的影响.研究结果表明,磨细钢渣具有令人满意的减水效果且与混凝土减水剂有较好的适应性;适量磨细钢渣掺入混凝土中对混凝土抗压强度以及耐久性能影响不大;将磨细钢渣与磨细粉煤灰或矿渣混掺可以发挥复合效应,提高掺合料的活性,改善混凝土的性能.     

钛矿渣粉对水泥砂浆性能的影响

研究了不同TiO2含量的钛矿渣粉对水泥砂浆强度和流动性能的影响。结果表明，钛矿渣活性随TiO2含量升高而减小；掺钛矿渣的水泥抗压强度总体随钛矿渣掺量增大而明显降低，而抗折强度较抗压强度下降幅度低，特别是后期抗折强度下降趋势明显趋缓。掺钛矿渣的水泥砂浆的流动度随掺量增大而增大，最高可提高约40％。综合来讲，钛矿渣中TiO2含量在20％以下，掺量在30％-50％，可以较好地应用于水泥中。