Study On High Strength High Performance Self Compacting Concrete Containing Lithium Slag Composite Slag

The mineral additives such as fly ash, granular blast-furnace slag and silicon fume are necessary components of high-performance concrete, and its application in concrete has been studied for many years. But plenty of industry offal such as lithium slag and stone fragment have not been well utilized for a long time in my country, which leads to environment pollution and resource waste. How to make the most of the above materials in self-compacting concrete in order to enlarge mineral additives source become present key question.Using super fine lithium slag as the main mineral additive, by combinations of exerting common technics and cure ways, the compound effects of workability, mechanical properties, durability(chloride ion penetration resistance, carbonization resistance, shrinkage) of the concrete adding lithium slag alone(LC), adding lithium slag and limestone powder(LLC), adding lithium slag and silicon fume admixture(LSC), adding lithium slag and fly ash admixture(LFC), adding lithium slag and slag admixture(LSC) were studied.This research work has led to the following findings.â‘ The best addition content of lithium slag in self compacting concrete is 15%. The Slp of the concrete is 272mm, the Lsf is 731mm, the result of L rheolegical instrument is 0.88. After added with 15% lithium slag, the best addition content of limestone powder is 30%, and the Slp of the concrete is 264mm, the Lsf is 702mm, the result of L rheolegical instrument is 0.83. The best addition content of silica fume is 5%, and and the the Slp of the concrete is 262mm, the Lsf is 703mm, the result of L rheolegical instrument is 0.82. The best addition content of fly ash is 30%, and the the Slp of the concrete is 261mm, the Lsf is 678mm, the result of L rheolegical instrument is 0.91. The best addition content of slag is 30%, and the the Slp of the concrete is 263mm, the Lsf is 674mm, the result of L rheolegical instrument is 0.80. All of the concretes can meeting with the level of self-compacting concrete.â‘¡The compressive strength of concrete which added with lithium slag alone or with other composite addmixture is 50MPa at 7d, meeting with the level of high strength concrete. Added with 15% lithium slag and 10% limestone powder, the compressive strength of concrete is 102MPa at 90d. Added with 15% lithium slag and 5% silica fume, the compressive strength of concrete is 114MPa at 90d. Added with 15% lithium slag and 20% fly ash, the compressive strength of concrete is 106.5MPa at 90d. Added with 15% lithium slag and 15% slag, the compressive strength of concrete is 101MPa at 90d. All of the concretes can meeting with the level of super high strength concrete.â‘¢Adding ultra-fine lithium slag alone or with other composite admixture can improve the Cl^- penetration resistance of concrete, the best one is adding with lithium slag and silica fume. The concrete have no carbonization depth at 56d when adding lithium slag alone, lithiumand silica fume admixture, lithium slag and slag admixture. The most carbonization depth of concrete is 9.5mm at 56d when adding lithime salg and limestone powder admixture. The most carbonization depth of concrete is 10mm at 56d when adding lithime salg and fly ash admixture. But the carbonization depth is less than the depth of protection density. After the preview of age limit, the concrete have good durability in 100 years. The shrinkage of concrete added with lithium slag alone is small, and it is increasing when added with other composite admixture, but it is in permission.â‘£It has been showed by microcosmic analysis of early hydrate of cement pastes, that the concrete's structure added by lithium slag alone and other admixtures is comparing compact, on which the floccule covering, and forming the compact net structure by touching with the acicular. No any Ca(OH)₂ with hexagonal shape have been discovered in the SEM. It has been showed by the XRD trials, that the early extent of hydration is low. There were many C-S-H gels in the hydration and the crystals of CH have become finer, which is beneficial to the strength of the pastes.So the self compacting concrete containing lithium slag composite slag has good workability, mechanical properly, chloride ion penetration resistance, carbonization resistance and other durability. In the research, the cement can be replaced by mineral admixture in 45%, it can decrease the environment load obviously, and it can also guide to the use of mineral admixture in self-compacting concrete. So it has good practicality value and even good economy benefit.