采用开流磨和闭路磨的两种水泥和石灰石粉为主要原材料,分别配制了2组混凝土试样进行碳化实验,研究了其在不同养护条件下颗粒分布对混凝土抗碳化性能的影响.在同种养护条件和配合比情况下,水泥颗粒分布宽的混凝土抗碳化性能高于水泥颗粒分布窄的混凝土;颗粒分布宽的水泥水化速度高于颗粒分布窄的水泥.

本文探究了多元醇类生料助磨剂在立磨中对水泥生料粉磨效果的影响.结果表明,添加适量生料助磨剂可以提高生料立磨台时产量,降低生料粉磨电耗,对生料的颗粒分布影响不大;使用生料助磨剂所增加的生产成本与节电效益相比没有优势,但在水泥窑增产潜力大,生料磨能力偏小的情况下,可以使用生料助磨剂来提高生料产量,进而增加熟料的产量,实现效益的增加.

本文以四种熟料矿物组成不同的P·Ⅱ42.5R水泥、Ⅱ级粉煤灰和石灰石粉为胶凝材料,配制成三个混凝土系统:纯水泥系统A、掺粉煤灰系统B和掺石灰石粉系统C.A系统进行(20±2)℃、相对湿度大于95％的标准养护,B和C进行(15±1)℃、相对湿度(60±5)％的非标准养护.养护28 d后,进行加速碳化试验.试验得出的结果为:在温度(20±2)℃、相对湿度≥95％的标准养护条件下,高C2S含量的水泥配制成的混凝土试件具有更好的抗碳化性能;在温度(15±1)℃、相对湿度(60±5)％的非标准养护条件下,水化更快的高C3S含量的水泥配制成的混凝土试件相对而言具有较好的抗碳化性能.提高混凝土抗碳化性能要做好养护工作.

为研究胶凝材料的差异对混凝土疲劳特性的影响,采用4点加载的弯曲疲劳实验方法,对比研究了不同应力水平下低热硅酸盐水泥和同强度等级的普通硅酸盐水泥配制混凝土的弯曲疲劳特性,利用DTA-TG、SEM和MIP探讨了两种不同水泥配制混凝土的微观组成结构差异及其对疲劳特性的影响.实验结果表明:28、90 d和180 d标准养护条件下的低热水泥混凝土在应力水平为0.75～0.90时的弯曲疲劳寿命均高于普通硅酸盐水泥混凝土;3.49 MPa应力荷载下,养护龄期由28 d延长至180 d,两种混凝土的弯曲疲劳寿命分别提高了230 452及8 168倍,90 d与180 d养护龄期的低热硅酸盐水泥混凝土的疲劳寿命分别是普通硅酸盐水泥混凝土的4.76倍及19.88倍,养护龄期越长,低热水泥混凝土抗疲劳性能的优势越显著;低热水泥混凝土水化产物中C-S-H凝胶多,Ca(OH)2含量少,加载后最可几孔径与大孔含量的增幅较低(＜10％),致使其在疲劳荷载作用下裂缝源生成的可能性减少,裂缝扩展能力降低,抗疲劳能力增强.

Different shaped K0.3WO3 blue pigments were prepared by a simple solvothermal method. The as-synthesized K0.3WO3 pigments were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and spectrophotometer. It's found that the concentration of WCl6 had a great influence on the morphology of K0.3WO3 pigments. Spindlelike K0.3WO3 composed of nanorods, microsphere structures composed of nanorods and microflower structures composed of nanosheets could be obtained with an increasing WCl6 concentration. The obtained spindle shaped K0.3WO3 showed higher near infrared shielding ability than that of K0.3WO3 microspheres and microflowers. The reason could be attributed to the enhanced local surface plasmon resonance absorption induced by higher aspect ratio and higher free carrier concentrations of spindleliked K0.3WO3. An approximately 8.5 degrees C decrease in inner temperature was obtained for the heat box covered with K0.3WO3 coated glass. Therefore, the synthesized K0.3WO3 blue pigments with high visible light transparency and high near infrared shielding ability have the potential to be applied in smart window coatings to reduce the heat build-up.

In this work, hollow glass microsphere/BiOBr1-xIx composites was synthesized as a series of novel colored near infrared reflective pigments. BiOBr1-xIx microflowers or microspheres were deposited on hollow glass microspheres using a simple chemical liquid deposition method. The morphologies and optical properties of the composite pigments were found to differ drastically by varying the molar ratio of I to Br. The color of the composite pigments was observed to turn from white to yellow, and then to red as the increased content of I. The band gap of the composites decreased from 2.87 to 1.87 eV with increasing I content. The near infrared solar reflectance of hollow glass microsphere/BiOBr1-xIx composite pigments was as high as 0.952. An approximately 9.4 degrees C decrease in outer surface temperature was obtained for the heat box coated with the composite pigments. Therefore, the synthesized composite pigments with tunable colors and high NIR reflectance have the potential to be applied as cool pigments in cool coatings to reduce the heat build-up.

AA-TPEG-AMPS polycarboxylate superplasticizer(ATS) was synthesized by introducing 2-acrylamide-2-methacrylic acid(AMPS) into the structure of traditional AA-TPEG polycarboxylate(PCE).A study including adsorption and XRD experiments revealed that the adsorption of ATS on montmorillonite did not differ much from PCE.The adsorption capacity of ATS on the cement particles is less than that of PCE.However,the adsorption layer thickness and the absolute value of the zeta potential of ATS are larger than that of PCE.Therefore,ATS exhibites a good dispersion property in cement-clay system.

In this work, BiOCl1,I-x(x) coated hollow glass microsphere was synthesized as a novel near infrared reflective pigment for superhydrophobic cool roof coatings. BiOCl1-I-x(x) microflowers or microspheres were deposited on hollow glass microspheres using a simple chemical liquid deposition method. The morphologies of BiOCI1-x.I-x were found to differ drastically by varying the molar ratio of Cl to I. The color of the composite pigments changed from white to red and the band gap decreased from 3.16 eV to 1.87 eV as the increased content of I. The near infrared solar reflectance of the composite pigment was as high as 0.947. An approximately 8 C decrease in outer surface temperature was obtained for the heat box coated with the composite pigments. With the help of the micro/nano-scale surface roughness of hollow glass microsphere/BiOCl1-xIx composites, a superhydrophobic coating with a contact angle of 156.1 could be obtained. The superhydrophobic cool coating showed good antifouling property when they were fouled by the slurry solution containing montmorillonite and Rhodamine B. Moreover, the prepared superhydrophobic coatings exhibited long term stability and ultraviolet durability. Therefore, such superhydrophobic cool coatings with antifouling property is able to work for a longer time by preventing the contamination for building thermal insulation.

Hollow glass microsphere/ZnO composite pigments were successfully prepared by a facile sol-gel method. ZnO coating layers composed of nanosheets, nanoplates, or nanoparticles were anchored at the surface of hollow glass microspheres by formation of Zn-O-Si bond. A reasonable growth mechanism for elucidating the formation of ZnO nanocoating was proposed. The results indicated that the near-infrared reflectance property of the composite pigments was strongly affected by the morphology of ZnO nanostructures. The nanoparticles structures exhibited higher near-infrared reflectance than that of nanosheets and nanoplates structures. The near-infrared solar reflectance of hollow glass microsphere/ZnO composite pigments was 95.7%, while the total solar reflectance of the composite pigment was as high as 97.2%. An approximately 11.1°C decrease in outer surface temperature was obtained for the heat box coated with composite pigments. Therefore, hollow glass microsphere/ZnO composites are excellent near infrared reflective pigments for efficient solar reflective coatings designed for building facades and roofs.

To obtain cool yellow pigments with high near-infrared reflectance, mica/Fe2TiO5 composite pigments were synthesized by a chemical liquid deposition method. The developed composite pigment powders were characterized by X-ray diffraction (XRD), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV vis NIR diffuse reflectance spectra, and CIEL*a*b* color scales. Different sized Fe2TiO5 nanorods were coated on the surface of mica particles. The particle size of the nanorods increased with increasing molar ratio of Fe3+ to Ti4+. The obtained composite pigments showed strong ultraviolet shielding ability and high near-infrared reflectance property. What's more, the Fe2TiO5 coating with smaller particle size possessed higher reflectance in the region of 700-1500 nm in accordance with the Kubelka-Munk theory. The near-infrared solar reflectance of mica/Fe2TiO5 composites was as high as 80.3%. An approximately 3 degrees C decrease in interior temperature was obtained for the heat box coated with the composite pigments. Furthermore, the composite pigments exhibit brilliant yellow colors. Therefore, mica/Fe2TiO5 composites are excellent near infrared reflective yellow pigments for efficient solar reflective coatings. (C) 2017 Elsevier Ltd. All rights reserved.

新拌水泥砂浆可近似看作宾汉姆流体,其流变参数的表征对于研究砂浆和混凝土的工作性能具有重要意义.文中通过测定每100mL砂浆在其上部砂浆重力作用下从漏斗中流出的速率来绘制流变曲线,经过线性拟舍得到砂浆的塑性黏度和屈服应力来对砂浆的流变性能进行表征;研究了装料筒下料口直径和接料量筒内径对测试结果的影响,并与旋转黏度计法所得结果进行比较,分析了文中方法的可靠性与可重复性.结果表明:文中方法的测试结果不受砂浆中砂粒大小的影响,可重复性好;所选测试条件为自身重力下的低剪切速率条件,与混凝土的施工性能状态更为接近;两种方法所测塑性黏度、屈服应力的绝对值虽有差异,但在比较样品间流变参数大小的规律方面是一致的.

The influence of Sn4+ doping on the photoactivity inhibition and near infrared reflectance property of mica-titania pigments was investigated. X-ray diffraction analysis confirmed that Sn4+ doping promoted phase transformation from anatase to rutile. The rutile promoting effect of Sn4+ can be ascribed to the distortion of the crystal structure of anatase after the replacement of Ti4+ by Sn4+. Sn4+ doping had a great influence on the photoactivity of mica-titania pigments. The photoactivity of mica-titania pigments was enhanced at low dopant levels, whereas its photoactivity was inhibited at high dopant levels. Remarkably, the degradation rate constant of mica-titania pigments doped with 1.0 wt% of SnCl4 was approximately 12.9% of that of the undoped sample. A possible mechanism for this effect was proposed. Moreover, the near-infrared solar reflectance of mica-titania pigments reached 0.97. An approximately 8.3 degrees C decrease in temperature was obtained for the inner surface of a calcium silicate board coated with mica-titania pigments. Furthermore, a solar reflective coating coloured with low photocatalytic mica-titania pigments exhibited high photostability against weathering conditions. Therefore, mica-titania pigments with high levels of the Sn4+ dopant are excellent candidates for use in solar reflective coatings. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Nanometer titanium dioxide was deposited on hollow fly ash beads using a chemical liquid deposition method. Surface modification of hollow fly ash beads with Ca(OH)2 saturated solution resulted in the presence of calcium silicate hydrate. The surface modification had a great influence on the growth and micro-morphology of TiO2 nanoparticles on the surfaces of hollow beads. Electrostatic repulsive forces between the modified hollow bead surfaces and hydrated TiO2 were significantly reduced after the surface modification, favoring the formation of a homogeneous and uniform TiO2 film with high TiO2 loading. A possible growth mechanism of TiO2 coatings was proposed. Moreover, the near-infrared solar reflectance of hollow bead/TiO2 composite pigment reached 0.68, which was approximately 1.8 times as high as that of hollow beads. An approximately 28.1°C decrease in temperature was obtained for the inner surface of a calcium silicate board coated with composite pigments. Therefore, hollow fly ash bead/TiO2 composite pigments are excellent candidates for near-infrared reflective pigments used in solar reflective coatings.

The influence of the seed layer on the phase composition and photoactivity inhibition of mica-titania pigments was investigated. The prior deposition of MnO2 or SnO2 as a seed layer resulted in a complete rutile TiO2 coating without calcinations, while the prior deposition of ZnO led to a mixture of anatase and rutile. The rutile promoting effect of MnO2 and SnO2 could be ascribed to the small lattice mismatch (< 5%) between the seed layer and the rutile TiO2. Moreover, the seed layer had a great influence on the photoactivity inhibition of mica-titania pigments. A seed layer of MnO2 inhibited the photoactivity of the pigments, whereas a seed layer of SnO2 or ZnO enhanced the photoactivity of the pigments. The degradation rate constant of mica-MnO2-TiO2 was approximately 72.7% that of mica TiO2, while the degradation rate constant of mica-SnO2- TiO2 was approximately 4.5 times as high as that of mica-TiO2. The influence of the seed layer on the photoactivity of mica-titania pigments depended on the transfer process of electron hole pairs between the seed layer and TiO2. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Different shaped rutile TiO2 coated mica-titania pigments were prepared by hydrolysis of TiCl4 ethanolic solution at 70 degrees C. SnO2 as a rutile promoting additive was deposited onto mica prior to TiO2. The use of TiCl4 played a crucial role in controlling the morphology of rutile TiO2 coatings. Monodisperse nanoneedles were assembled into nanoflowers with an increasing particle size as the TiO2 loading increased. A possible crystal growth mechanism of rutile TiO2 with rich nanostructures was proposed. The obtained rutile samples showed stronger ultraviolet shielding ability and higher near-infrared reflectance property than that of anatase sample. What's more, the rutile TiO2 coating with smaller particle size possessed higher reflectance in the region of 1300-2500 nm in accordance with the Kubelka-Munk theory. The near-infrared solar reflectance of the rutile TiO2 coated mica-titania pigment was as high as 97%, making them good candidates for solar reflective pigments. (C) 2014 Elsevier Ltd. All rights reserved.

通过化学结合水分析、水化热分析和DTA-TG分析,研究了三乙醇胺(TEA)、三异丙醇胺(TIPA)和乙二醇对A矿水化的影响 研究结果表明,TEA、TIPA和乙二醇使A矿28d以前龄期的化学结合水量提高,水化热增加,水化速率加快,对A矿水化的促进作用为TEA＞TIPA＞乙二醇;28d及其以后的龄期水化率和空白样接近.

The effect of cement with different clinker mineral content on fatigue resistance,impact resistance and wear resistance of concrete was studied.The results indicated that if the content of C3S and C2S of different clinker kept at similar level,the fatigue resistance,impact resistance and wear resistance at 28 and 90 days of concrete would be increased with increasing of C4AF content.If the content of C3S was enough to meet the strength requirement of cement and the fusing minerals(C3A,C4AF) content was similar,the fatigue resistance,impact resistance and wear resistance of concrete prepared with low C3S and high C2S content cement were better than that prepared with high C3S and low C2S content cement.So,if the content of C3S was enough to meet required strength and fusing mineral content was 19%-20%,it was profitable to improve the performance of concrete with the content of C4AF and C2S increased appropriately.

In this work, nanoflower arrays of rutile TiO2 composed of nanorods were directly grown onto mica substrates through hydrolysis of TiCl4 ethanolic solution in water at 70 degrees C without calcination. SnO2 as a rutile promoting additive was deposited onto mica prior to TiO2. The rutile promoting effects of SnO2 could be ascribed to the structural similarity of rutile and cassiterite. The nanorod crystals grew along the [0 0 1] direction, forming predominantly exposed {1 1 0} side-facets and {0 1 1} top-facets. A reasonable growth mechanism for elucidating the formation of rutile TiO2 nanoflower arrays was proposed. The obtained nanoflower arrays of rutile TiO2 coated mica particles show excellent photocatalytic activity towards degradation of rhodamine B (RhB) under UV illumination, which is almost 1.9 times as high as that of Degussa P25. The enhanced photocatalytic activity of rutile TiO2 superstructures can be ascribed to the combined contribution of high crystallinity, low band gap, and effective separation of electrons and holes by the synergistic effect between the exposed {1 1 0} and {0 1 1} facets of the rutile nanorods. Furthermore, we demonstrated that these rutile TiO2 coated mica particles can be easily recycled without decrease of the photocatalytic activity, which provide possibility to future industrial applications in environmental pollutants cleaning up. (c) 2013 Elsevier B.V. All rights reserved.

In this work, we report a facile strategy to fabricate hierarchical rutile TiO2 thin film on mica substrates through hydrolysis of TiCl4 ethanolic solution in water. Scanning electron microscopy (SEM) and transmission electron microscope (TEM) analysis reveal that the rutile TiO2 film is composed of nanorods and nanoparticles. The nanorod crystals grew along the [101] direction, forming predominantly exposed {110} facets. Interestingly, rutile TiO2 coated mica particles can be directly applied as a general kind of building blocks to construct large-area super hydrophilic surfaces without UV irradiation by the simple spin-coating technique. The superhydrophilicity originates from the combination of the special rough structures of hierarchical nanorods and nanoflowers and the increased hydroxyl content caused by calcinations. More importantly, this property is very stable for half a year and could be used in self-cleaning surfaces. (C) 2013 Elsevier B.V. All rights reserved.