【作者】 胡志远；

【导师】 陈剑雄；

【作者基本信息】 重庆大学 ， 材料科学与工程， 2008， 硕士

【摘要】 掺加活性矿物掺合料是制备高性能混凝土的必要条件之一。在混凝土中掺加矿物微粉,不仅具有较好的经济效益,而且还能够改善混凝土的工作性能、力学性能和耐久性。矿物掺合料是高性能混凝土中不可缺少的组分,粉煤灰、粒化高炉矿渣和硅灰是我国常用的矿物细掺料,其在混凝土中的研究应用已经很多。研究如何在混凝土中充分利用这些废渣、废料以扩大矿物掺料的来源成为当前亟待解决的问题。本课题以超磨细锂渣为主要矿物掺合料,采用“双掺”的技术,研究单掺锂渣的混凝土（LC）、复掺锂渣与硅灰的混凝土（LSC）、复掺锂渣与粉煤灰的混凝土（LFC）、复掺锂渣与矿渣的混凝土（LSC）的工作性能、力学性能及耐久性（抗Cl^-渗透性、抗碳化性）。通过上述工作得到如下结果:①锂渣是一种具有较高潜在火山灰活性的矿物掺合料,具有良好的易磨性,可以通过粉磨对其粉体粒子的表面进行改性,增大其活性。原状锂渣经34min磨细后,可制成比表面积可达14000 cm²/g超磨细锂渣。将其掺入混凝土中对其工作性改善越明显。但锂渣粉磨后期,比表面积增长较慢,单纯的增加粉磨时间并不可取,因此在制备混凝土时,选择掺入磨细34min的锂渣。混凝土中胶结材掺量以600kg/m³到650 kg/m³之间为宜;②掺入超磨细锂渣可以配制出工作性能优良的混凝土。锂渣在混凝土中的最佳单掺量为15%。固定锂渣掺量15%后,硅灰最佳复掺量为5%,粉煤灰最佳复掺量为30%,矿渣最佳复掺量为25%;③单掺入锂渣,混凝土3d强度随其掺量的增加逐渐降低,但降幅不明显。掺量小于15%时,混凝土初期和后期强度均优于空白混凝土。综合各龄期混凝土抗压强度,锂渣在配制混凝土中的最优掺量为15%,此掺量下除初期3d强度外,各龄期强度均优于空白混凝土;④硅灰具有明显的增强效应,其与锂渣复掺复合效应良好。在固定掺入15%超磨细锂渣后,硅灰的最佳复掺量为5%。早期3d、28d以及后期的90d强度,复掺硅灰组抗压强度较对比单掺组增长都比较明显。超磨细锂渣与粉煤灰及矿渣同样具有良好的复合效应。固定超磨细锂渣掺量15%后,粉煤灰的最佳复掺量为20%,矿渣的最佳复掺量为15%。在混凝土后期强度方面,复掺组均优于单掺锂渣组;⑤由扫描电镜实验和X射线衍射实验可知,掺入超磨细锂渣等掺合料,混凝土中的水化产物C-S-H凝胶增多,Ca（OH）₂含量减少,且晶粒细化,同时由于磨细锂渣以及其它矿物细掺料的紧密堆积作用,可以很好的改善混凝土密实性,从而提高其强度;⑥混凝土中单掺入超磨细锂渣可以有效地改善其抗氯离子渗透性能,复掺入锂渣和硅灰,可以大幅的改善混凝土抗氯离子渗透性能,其氯离子扩散系数降幅达60%以上,分别复掺入粉煤灰和矿渣在56d时仍能有效地改善混凝土抗氯离子渗透性能;⑦单掺入超磨细锂渣混凝土56d内基本无碳化,胶结材掺量对混凝土碳化影响不大。固定锂渣掺量为15%的前提下,复掺入硅灰组混凝土56d基本无碳化。更多还原

【Abstract】 It is one of the requirements of preparing the high-performance concrete to mix with active mineral admixture.To mix in the concrete with the mineral powder does not only have better economic benefits,but also can improve the workability,mechanical properties and durability of the concrete.Mineral admixture is indispensable component of the high-performance concrete.Fly ash,granulated blast furnace slay and silica fume are commonly used as the mineral admixture in China,and have been already widely applied in concrete.How to fully utilize the waste residue,waste material has become the problem to be solved urgently at present in order to expand source of mineral admixture in the concrete.This subject regards super fine lithium slag as the main mineral and adopt the technology of "double-mixing" to study the workability,mechanical properties and durability（anti-Cl^--permeability,anti-carbonization） of the concrete mixing lithium slag only（LC）,mixing lithium slag and silica fume（LSC）,mixing lithium slag and fly ash （LFC）,mixing lithium slag and slag.Results and conclusion of this thesis are as follows:①The lithium slag is a kind of mineral admixture with higher potential pozzolanic activity and has good grindability.Modifying the surface of the powder through fine-grinding can increase its activity.Original state lithium slag can be made to super fine powder with specific surface area up to 14000 cm²/g after grinding for 34min. Mixing it into concrete can obviously improve the workability of the concrete.But the specific surface area of the lithium slag increases slowly at the later stage of grinding, so it is inadvisable to simplely increase grinding time and mixing the lithium slag ground for 34min is advised while preparing concrete.The mixing amount of glued material is between 650 kg/m³ with 600kg/m³ in the concrete;②Mixing super fine lithium slag can produce the concrete with good workability. The optimum single-mix amount in the concrete is 15%.With fixing the mix amount of lithium slag to 15%,the optimum double-mix amount of microsilica,fly ash and slag are 5%,30%and 25%respectly.③With mixing lithium slag only,the 3d strenth of concrete reduces with increase of mix amount gradually,but decreasing amplitude is not obvious.When the mix amount is less than 15%,the initial strength and later strength are superior than that of the blank concrete.From the compressive strengths of the concrete in different age,the optimum mix amount of lithium slag in concrete is 15%.With the optimum mix amount, the strength at every age is superior than that of the blank concrete besides initial 3d strength.④Microsilica has obvious enhancement effect,and mixing it with the lithium slag can get good compound effect.With fixing the amount of super fine lithium slag to 15%, the optimum double-mix amount of microsilica is 5%.The increase of compressive strength in 3d,28d and 90d of the concrete double-mixing with microsilaca is more abvious than that of the concrete single-mixing with lithium slag.Mixing lithium slag with fly ash or slag can also get good compound effect.When fixing the amount of super-fine lithium slag to 15%,the optimum double-mix amounts of fly ash and slag are 20%and 15%respectly.In the respect of later strength,the concrete doubel-mixing is superior than the concrete single-mixing lithium slag;⑤From the results of SEM and XRD,it was found that after mixing mineral admixtures such as lithium slag,etc.,the amount of C-S-H gel increased in the concrete, the amount of Ca（OH）₂ reduced,and grain refinement took place.Meanwhile,because of the compact stacking interaction of the lithium slag and other mineral admixtures,the density of the concrete can be improved and the strength of the conrete can increase;⑥The ability to resist chloride ion penetration of concrete can be improved effectively by mixing super-fine lithium slag powder.Double-mixing lithium slag and microsilica can improve the ability to resist chloride ion penetration of the concrete by a wide margin,and the amplitude of the chloride diffusion coeddicient is more than 60%. The ability to resist chloride ion penetration of the concrete double-mixing with fly ash and slag respectly can also be improved effectively in 56d;⑦No carbonization took place in 56d concrete single-mixing with super-fine lithium slag.The amount of glued material has little effect on carbonization of concrete. With the amount of lithium slag fixed to 15%,no carbonization took place in the 56d concrete double-mixing with microsilica.更多还原