Research And Application Of High Titanium Heavy Slag Aggregate Of High Performance Concrete

High titanium heavy slag of Panzhihua Iron & Steel is a stone-based material composed by titanaugite, perovskite and other mineral which produced by molten slag cooling in the air or water when smelting vanadium-titanium magnetite. The content of TiO2 by chemical composition in high titanium heavy slag of Panzhihua Iron & Steel is more than 20% makes it quite different from ordinary slag in performance and is not suitable for production of cement admixture and the mineral admixture of concrete, Leeds to seldom used in concrete and building mortar, greatly limits the utilization of high titanium heavy slag. Panzhihua Iron and Steel Company currently has 50 million tons of high titanium heavy slag which has not been effective use, it has gravely restricted the production of Panzhihua Iron & Steel. A large-scale, resource conservation and efficient use of high titanium heavy slag of Panzhihua Iron & Steel is therefore extremely urgent.This article relies on transportation projects in Western "The research and application of high performance bridge concrete use high titanium heavy slag as aggregate", takes advantage of characteristics like that high strength, chemical stability, discussing as a coarse and fine aggregates instead of natural river sand, gravel to produce high performance bridge concrete through mixing fly ash and other mineral admixture to optimize concrete mix ratio, conducting the following research work.The chemical composition of high titanium heavy slag are CaO and SiO2, and the content of TiO2 are more than 18%, the mineral composition and structural stability of high titanium heavy slag are researched. Compared with ordinary gravel aggregate, the apparent density, bulk density is slightly lower, the volume stability and water absorption is better, and there are many holes, and non-Alkali reactivity of aggregates. High titanium heavy slag can be used in bridge high performance concrete instead of gravel and river sand.Fixed sand volume method is used to design the high titanium heavy slag high performance bridge concrete mix proportion, The influence of the coarse aggregate volume, volume content of sand, fly ash, dust content, pre-wet time to the workability and mechanical properties of high titanium slag concrete are researched. The results showed:when the volume of fly ash is 20 to 30%,coarse aggregate volume is 0.7-0.75m3, sand volume in mortar content is 0.50 to 0.55 m3.Slag sand dust content is under 15%, workability and mechanical properties of high titanium heavy slag of high performance concrete had no effect. High titanium heavy slag aggregate is must be pre-wet maintaining water of about 7h to improve the workability of concrete. Concrete admixture mixed with water holding and viscosity increasing components can effectively increase the cohesion of high titanium-bearing BF slag concrete and improve pumping workability of concrete.The compressive strength, flexural strength, splitting tensile strength, compression,creep coefficient of C30-C50 high titanium heavy slag concrete and other mechanical properties is similar with the same intensity of ordinary gravel concrete. Both of them can meet the requirements of high performance bridge concrete. The early anti-cracking performance, free shrinkage, drying shrinkage of high titanium heavy slag concrete are better than ordinary gravel concrete. The impermeability, carbonation resistance and sulfate resistance of high titanium heavy slag concrete are similar with ordinary gravel concrete, It can also meet the durability requirement of high performance bridge concrete.Research results are used in the Lijiang to Panzhihua expressway pile, pier and bridge structure for large volume and other parts. Practical application shows that: The high titanium heavy slag concrete can fully meet the requirements of pumping concrete with excellent performance, strength and durability performance.