Influence of Temperature on Sulfate Attack of Limestone Filler Cement Mortar

Mortar prisms were made with three different cementitious materials (with or without mineral admixture) plus 30% mass of limestone filler. After 28 days of curing in water at room temperature, the mortars were submerged in 2% magnesium sulfate solution at different temperatures (5℃, 20℃and alternate temperature between 5℃and 20℃) for a year. The appearance and strength development were measured on these immersed prisms at intervals, and samples selected from the surface of prisms were examined by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The results show that the influence of temperature on the resistance to sulfate attack of mortar is related to the binder compositions. A higher temperature leads to a quicker strength loss and appearance deterioration of the mortar without mineral admixture. For blended cements, a higher temperature is favorable for the pozzolanic reaction of mineral admixture and the overall deterioration of mortar is reduced with the increasing temperature. When the mineral admixture has a lower reactivity, such influence of temperature on the resistance to sulfate attack of mortar containing admixtures becomes greater. At the three different solution temperatures, two blended cements show significantly improved resistances to sulfate attack. After 1 year of exposure to magnesium sulfate solutions, the formation of thaumasite was checked in the OPC mortars at both 5℃and 20℃. It is concluded that the thaumasite formation is not limited to structures at low temperature (less than 15℃).

Interaction between PCC Filler and Cellulosic Fiber in Fiber/Filler Co-refining System

Mineral fillers are important for conserving raw fiber materials and reducing production costs in the paper industry.However,the increase in filler content will inevitably result in strength reduction,which limits the adding amount of filler in paper production.In this study,we designed a cellulose fiber/filler co-refining approach to improve the strength and optical properties of paper;moreover,the synergistic interaction between fibers and precipitated calcium carbonate(PCC)fillers in the co-refining process was investigated.Results of fiber separation and PCC particle size analysis showed that,compared with conventional refining,the content of fines increased,whereas the PCC particle size decreased.More importantly,composites were formed between the PCC and fines,which promoted strength improvement of paper.Physical tests show that the tensile index of paper with 15%PCC content increased by 22%compared with that of the paper filled by conventional method,whereas the brightness and opacity of paper improved by fiber/filler co-refining for a specified filler content.These findings provide a basis for the further development of co-refining filling technology.

An Experimental Study of Self-Compacting Concrete Made with Filler from Construction and Demolition Waste

This study evaluated the influence of the Portland cement replacement by 0, 5%, 10%, 15% and 20% of Construction and Demolition Waste (CDW) filler contents in the production of self-compacting concrete (SCC). The SCC mixtures were evaluated on fresh state by slump flow, J-ring, resistance of segregation, specific gravity, and on hardened state by compressive and splitting tensile strength, specific gravity, air voids and absorption rate. The results indicated that all SCC produced with CDW filler met the limits established at any level of substitution without changes of the w/c ratio or superplasticizer content. It was possible to verify that the presence of CDW filler, in substitution of cement, by volume, improves the resistance to segregation and up to 5% of CDW filler decreases the loss of fluidity with time as compared to reference. It was found that all SCC mixtures, at 28 days, had the average compressive strength above 50 MPa, without showing significant loss with up to 20% of CDW filler. For splitting tensile strength, SCC recycled mixtures reached up to 92.5% of the SCC used as reference. Absorption rate and air voids index of SCC recycled mixtures had a maximum increase of 1.60%Compared to the reference one. So, it is possible to conclude that the use of the CDW filler up to 20% in substitution of cement, by volume, is feasible for SCC production.

矿物填料对水性超薄型防火涂料性能的影响

【目的】研究不同矿物填料及其复配比例对水性超薄型防火涂料性能的影响。【方法】以水性环氧/纯丙复配乳液作成膜物质;聚磷酸铵、季戊四醇、三聚氰胺作膨胀体系;钛白粉(TiO_(2))、煤矸石(CG)、膨润土(BT)、水滑石(LDH)作矿物填料进行了XRF、TG、FTIR和SEM分析。【结果】结果显示:单一矿物填料的防火性能由强到弱排序为TiO_(2),CG,BT,LDH.单一TiO_(2)填料防火涂料燃烧80min炭层膨胀倍率达到13.6,钢板背温为274.9℃,其炭层结构存在强度弱的问题。复配矿物填料能够达到高效防火、节能低耗、经济环保的目标,同时为矿物填料的高值化利用提供了一种新途径。当TiO_(2)、BT、LDH复配质量比为6∶2∶2时,燃烧炭层膨胀倍率为14.9,钢板背温仅为268.8℃;TiO_(2)、BT、CG复配质量比为8∶1∶1时,膨胀倍率为14.5,钢板背温仅为261.0℃,防火性能优于单一矿物填料。扫描电镜观测发现,BT、CG和LDH的加入使炭层表面结构更致密,结构更坚固。红外光谱分析可知,炭层的残留物中存在磷化物和金属氧化物,炭层结构强度增强。热重分析两种防火涂料的残炭量依次为36.35%、36.92%,炭层热屏蔽性能提高。

Influence of mineral fillers on the rheological response of polymer-modified bitumens and mastics

The rheological properties of the bituminous components （bitumen and bituminous mastic） within asphalt mixtures contribute significantly to the major distresses of flexible pavements （i.e. rutting, fatigue and low temperature cracking）. Asphalt mixtures are usually composed of mastic-coated aggregates rather than pure bitumen-coated aggre- gates. The purpose of this study is to investigate the effects of mineral fillers on the theological behaviour of several polymer-modified bitumens （PMBs） through laboratory mixing. A neat bitumen and two types of polymers （elastomeric and plastomeric） were used to produce PMBs, and two fillers with different minerals （limestone and basalt） were selected to obtain mastics. The dynamic shear rheometer （DSR） and bending beam rheometer （BBR） were used to characterize the theological properties of PMBs and mastics. In particular, multiple stress creep recovery （MSCR） tests were performed to evaluate the rutting potential at high temperatures, whereas BBR tests were carried out to investigate the low temperature behaviour of these materials. BBR results for unmodified mastics show that the increase of stiffness is similar regardless of the filler type, whereas results for polymer-modified mastics indicate that the degree of stiffening depends on the combi- nation of filler/polymer types. MSCR results show that adding filler leads to a reduced susceptibility of permanent deformation and an enhanced elastic response, depending on the combination of filler/polymer types. Overall results suggest that a physical-chemical interaction between the filler and bitumen occurs, and that the interaction level is highly dependent on the type of polymer modification.

基于文献和专利分析的有机防火涂料矿物阻燃填料发展趋势研究

矿物阻燃填料是传统防火涂料的重要组成部分。基于中国知网数据库、Web of Science数据库和国家知识产权局数据库,检索了1990年至2022年有机防火涂料中矿物阻燃填料研究的文献,介绍了矿物阻燃填料的研究应用情况。文献检索及专利分析表明:进入21世纪以后,国内外对矿物阻燃填料在有机防火涂料中的应用研究关注度呈增长趋势,研究热点主要集中在钢结构防火涂料、阻燃机理、表面改性、热稳定性等方面,矿物阻燃填料研究种类从以氢氧化铝、氢氧化镁为主逐渐转为以氢氧化铝、氢氧化镁、可膨胀石墨和黏土矿物为主,种类多样化、成分多样化和结构复杂化是近年来有机防火涂料中矿物阻燃填料的研究趋势,矿物阻燃填料的纳米化、协同阻燃以及表面改性等技术将不断得到发展。

6种矿物基填料的氨氮和磷吸附性能比较与作用机制

为高效去除污染水体中的氨氮(NH_(4)^(+)-N)和磷酸盐(PO_(4)^(3-)-P),筛选生态修复工程中吸附性能优异的矿物基填料,选取了3种天然填料(沸石、蛭石、火山岩)和3种加工型填料(陶粒、生物滤料、除磷滤料)开展NH_(4)^(+)-N、PO_(4)^(3-)-P的吸附动力学和等温线试验,结合X射线衍射、电子扫描显微镜等表征手段,对不同矿物基填料的吸附特性与作用机制进行对比和分析。结果表明:6种矿物基填料的NH_(4)^(+)-N和PO_(4)^(3-)-P吸附动力学过程均符合伪二级动力学方程,吸附速率主要受化学吸附过程控制。Langmuir和Freundlich方程都能很好地拟合不同矿物基填料的等温吸附曲线,NH_(4)^(+)-N的理论吸附容量排序为沸石(5.9416mg/g)>蛭石(3.6953 mg/g)>生物滤料(3.2500 mg/g)>除磷滤料(3.1389 mg/g)>火山岩(1.0000 mg/g)>陶粒(0.8571 mg/g),PO_(4)^(3-)-P的吸附容量大小为除磷滤料(4.2424 mg/g)>生物滤料(2.7917 mg/g)>蛭石(1.6250 mg/g)>陶粒(1.2105 mg/g)>火山岩(1.1579 mg/g)>沸石(0.5625 mg/g)。矿物基填料对NH_(4)^(+)-N和PO_(4)^(3-)-P的吸附特性与其比表面积、微孔结构、矿物组成和金属元素含量等因素相关,其中沸石的比表面积和阳离子交换量最大,对NH_(4)^(+)-N的吸附能力最强,生物滤料和除磷滤料中含有托贝莫来石、Ca、Fe等与磷结合能力较强的成分,对PO_(4)^(3-)-P的去除效果明显。综合来看,沸石和蛭石可用于NH_(4)^(+)-N污染水体的治理,生物滤料和除磷滤料可用于处理含磷污水,而治理同时含有NH_(4)^(+)-N和磷的污染水体时,可组合使用多种矿物基填料。对比其他填料,自主开发制备的生物滤料和除磷滤料在同步脱氮除磷方面具有明显优势,可作为氮、磷污染水体生态修复工程的优选基质。

Effect of Active Mineral Filler on Rutting Performance and Fatigue Properties of Granite Asphalt Concrete

Granite is well known as an acid aggregate. An active mineral filler produced in the laboratory is first used as an anti-stripping filler in the granite asphalt concrete. Four aggregate gradations were chosen in this study,and the effects of the active mineral filler and aggregates on the rutting resistance performance and fatigue properties of granite asphalt concrete were investigated by means of rutting test and four-point bending fatigue test. The results indicate that the dynamic stability of granite asphalt concrete increase significantly with the addition of active mineral filler and the fatigue properties can also be improved especially at lower strain level. Meanwhile,the results demonstrate that granite asphalt concrete has better rutting resistance performance and fatigue properties than limestone asphalt concrete.

矿物填料表面无机包覆改性研究

根据非均匀形核原理,采用合理工艺参数在均匀分散的CaO-H2O-CO2体系中,实现了矿物颗粒表面的纳米化包覆;分析了矿物颗粒表面纳米化修饰机理;用SEM、XRD和BET等检测技术对包覆前后的矿物颗粒进行了表征;与未包覆颗粒相比,复合颗粒不仅具有纳米颗粒的性能,同时还改善了微米颗粒的表面,使尖锐的棱角被钝化,平整光滑的解理面也因纳米级颗粒的修饰而变得粗糙,比表面积增加了300%以上.填充试验表明:复合矿物粉体在PP中填充,其粗糙的表面提高了与聚合物的相容性,缓解甚至消除了未包覆颗粒尖锐棱角和平整解理面所造成的复合材料内部的局部应力集中问题.

沥青混合料用矿粉性能指标研究

首先测量了5种不同类型矿粉的粒径、比表面积、亚甲蓝值、干捣空隙率和沉淀空隙率,同时进行了德国矿粉试验和液塑限试验,然后测试了各矿粉配制胶浆的使用性能,最后进行了矿粉指标与胶浆性能的相关性分析。试验结果表明:7种测试方法对矿粉性质有不同的适用性;矿粉类型对胶浆性能有重要影响,即有必要对矿粉类型进行筛选;考虑到测试方法的可推广性,推荐以干捣试验和德国矿粉试验作为矿粉高温性能和施工性能的评价方法,以亚甲蓝试验作为矿粉低温性能的评价方法。

粉胶比对沥青胶浆低温黏结强度的影响

选用SBS改性沥青,通过沥青胶浆低温黏结强度定量测试技术,研究了在不同低温条件下不同粉胶比对沥青胶浆低温黏结强度的影响机理,并确定了最佳粉胶比。研究结果表明:低温环境、粉胶比对沥青胶浆的低温黏结强度变化规律有显著影响。合适的粉胶比能够提高沥青胶浆的低温黏结强度。大粉胶比会产生填料附聚现象,截面附加破坏点基数增加,导致沥青胶浆低温黏结强度显著下降。此外,环境温度降低,沥青基体强度有所提高,但当温度低于沥青脆化点后,基体发生脆化,从而导致低温黏结强度显著降低。最佳粉胶比的确定应结合当地的低温条件,综合考虑沥青基体的黏结强度、沥青基体脆化状态及沥青填料界面强度效应。

无机矿物填料表面纳米化修饰及性能表征

采用化学方法对无机矿物填料表面进行包覆改性,制备出具有表面纳米化结构的复合矿物颗粒,有效地改善了原有颗粒的表面形貌,提高了比表面积.通过搅拌磨湿法研磨,讨论了包覆颗粒与基体的结合方式,初步证明了包覆颗粒与基体的结合方式为化学吸附而非物理吸附,两者结合牢固,包覆层不易脱落.包覆矿物颗粒在聚丙烯(PP)中填充,其复合材料的力学性能有较大的改善.

无机非金属矿物填料的研究进展

简要概述了无机非金属矿物填料出现的时代背景、填料性质及对聚合物性能的影响、应用技术现状以及未来的发展趋势 。

矿粉粒径对沥青胶浆性能影响的试验研究

为了研究矿粉粒径对沥青胶浆性能的影响,采用针入度、软化点、延度、表面能等试验,分析了沥青胶浆性能与矿粉粒径、粉胶比的关系,并从表面能的角度分析了其机理。研究结果表明:沥青胶浆粉胶比应采用试验后燃烧法确定的实际值;沥青胶浆的针入度、软化点、延度与实际粉胶比之间有良好的相关性;沥青胶浆的软化点随着矿粉粒径的减小而增大,而延度、针入度则随着矿粉粒径的减小而减小;沥青胶浆体系的粘附功是引起沥青胶浆性能随矿粉粒径、粉胶比变化规律的根本原因。

沥青混合料中矿粉用量、细度和密度指标的控制

在沥青混合料的组成材料中,矿粉的品质及其变异性的研究对于分析混合材料性能和组成材料的交互作用能力是极其重要。通过试验研究分析和说明了矿粉对混合料性能的影响。分析粉胶比、细度、用量及密度对混合料性能和组成的影响,提出了基于沥青混合料性能保证的矿粉品质参数的控制标准;提出粉胶比的控制范围,以及矿粉用量的容许控制范围;明确了矿粉0.075 mm通过率需要设立控制上限和下限,以往的单边控制存在一定的缺陷;提出了矿粉密度的容许变化范围。

稀土偶联剂在无机刚性粒子增韧聚丙烯体系中应用

利用力学性能、熔体流动速率等性能的测定等方法考察了一种稀土偶联剂(WOT)对CaCO3、BaSO4、Mg(OH)2、Mica和Talc等无机粒子的表面处理作用。发现经WOT处理的CaCO3与聚丙烯(PP)的复合物,在一定条件下缺口冲击强度可达到纯PP的2倍、断裂伸长率可达纯PP的3倍左右,表现出显著的无机粒子增韧效果;利用FTIR、SEM等考察了无机刚性粒子增韧PP的结构形态及增韧机理,表明WOT在处理过程中与CaCO3之间除了物理吸附作用外,还发生了化学作用,在CaCO3表面形成了牢固的包覆层,改变了无机粒子的表面性能;并且经WOT处理的CaCO3还具有β晶型成核剂的作用。

几种矿粉指标与沥青胶浆的关联分析

由矿粉和沥青组成的沥青胶浆是沥青混合料最重要的一种组成部分。虽然矿粉的用量在沥青混合料中所占的比重并不大,但在工程实践中经常会因为矿粉种类的改变而导致沥青混合料的路用性能产生很大的变化。本文采用灰色关联分析的方法,针对沥青胶浆的高、低温宏观性能与矿粉几种不同指标的关联度进行分析,得出这几种不同指标对沥青胶浆影响程度的大小关系。在评价沥青胶浆宏观路用性能时,用车辙因子表征胶浆的高温性能,粘度来表征低温性能。从而得出:在矿粉的这几种不同指标中,平均粒径对沥青胶浆的路用性能影响最大,密度其次,随后是0 02mm以下的颗粒含量和矿物组成,影响程度最小的是比表面积。这对于研究和改善沥青胶浆乃至沥青混合料的路用性能具有重要的指导作用。

微晶白云母活性填料的铝酸酯表面改性研究

以微晶白云母为研究对象,铝酸酯DL-411-D为改性剂,研究探讨微晶白云母铝酸酯表面改性工艺条件及其表征方法。经粘度和红外光谱研究证实粘度测试法是确定铝酸酯改性微晶白云母偶联剂用量的有效方法;铝酸酯偶联剂改性微晶白云母工艺简单,偶联剂用量低,不需使用稀释剂,成本低,效果好;改性后的微晶白云母在有机介质中的分散性得到显著提高,因而可大幅度提高其在高聚物中的填充量,降低复合材料的成本。实验结果还表明,铝酸酯改性微晶白云母后,没有发现化学结合的新证据,而更多地显示出物理包覆的特征。

非金属矿物橡塑填料应用现状及发展趋势

介绍了非金属矿物橡塑填料的特点和若干主要非金属矿物作为橡塑填料的应用研究现状；通过应用实例说明了天然矿物作为橡塑填料不仅可以改善橡塑的许多重要性能，而且可降低成本，有重要的应用价值和开发前景；从偶联剂。

基于动态粘弹力学的沥青胶浆高温性能试验研究

通过对粉煤灰、矿粉、消石灰、水泥4种矿物填料组成的沥青胶浆进行动态频率扫描试验和稳态流动试验,对4种不同矿物填料、不同粉胶比对沥青高温性能的影响进行了评价。研究表明:沥青胶浆的线粘弹范围小于沥青的线粘弹性范围;掺加4种矿物填料的沥青胶浆在代表胶浆的低温状态的高频区域内复合模量的增长趋向一致,在代表胶浆的高温状态的低频区域复合模量的差别变大;相同粉胶比下消石灰对沥青的高温性能提高最显著,其他依次为粉煤灰、水泥、矿粉,但后三者对沥青的影响差别不大;粉胶比的增加与复合模量、粘度的增加并不成正比例。