Ion Erosion Properties And Failure Mechanism Of Self-Compacting Lightweight Aggregate Concrete

Self-compacting lightweight aggregate concrete is based on the development of the lightweight aggregate concrete(LC) and the self-compacting concrete(SCC), it is made from light aggregate to replace the ordinary aggregate of an apparent density is less than 1950 kg/m3 new type of high performance concrete. Self-compacting lightweight aggregate concrete with enough plastic viscosity, the aggregate suspending in the slurry, there will be no segregation and bleeding phenomenon. Free flowing, full fill model space, form a compact and uniform structure. It is a kind of new green building material that have extremely extensive application prospect. Selfcompacting lightweight aggregate concrete research has just started, Lightweight aggregate concrete because of its particularity in terms of composition and structure.Light aggregate density is low and particle strength is low. in the process of mixing, transporting and molding easily rise, Lightweight aggregate concrete is easy to cause delimitation and segregation in the process of construction, In the practical engineering vulnerable to erosion from the outside environment, Especially the chlorine ion and sulfate ion. So to carry out the self-compacting lightweight aggregate concrete pumping performance and ion erosion research have important practical significance and economic significance.This paper adopts the round ball in grade 700 and 900 shale ceramist as coarse aggregate, add subtract agent, thickening agent and raw materials made from SCLC35 and SCLC50. Study its working performance and mechanical performance. Research shows that: Self-compacting lightweight aggregate concrete strength development conforms to the requirements. Choose the right type and dosage of thickening agent can better improve its workability.According to this article mixture preparation of SCLC can satisfy the engineering application of self-compacting and pumping performance requirements. The destruction of the SCLC is ductile fracture, Failure surface along the aggregate and cements paste, coarse aggregate broken into two parts. Coarse aggregate of compressive strength is low, coarse aggregate is weak area when the three-phase material compression of the self-compacting lightweight aggregate concrete is pressuring.According to the same mixture preparation made SCLC35 and SCLC50, under the condition of standard curing 28 days later, Into three groups in iron drum with solution soak: A group of soaking in clean water, A group of soaked in 5% sodium sulfate solution, A set of soaked in 5% sodium chloride and 5% sodium sulfate solution. Research the changes of appearance, quality and compressive strength as the erosion degree of evaluation standard.Research shows that: Chlorine ion and sulfate ion common spreading inside the concrete, with concrete hydration of calcium acuminate reaction. Respectively to generate more stable Frield salt and AFt salt. Self-compacting lightweight aggregate concrete using light aggregate has a lower modulus of elasticity and porous absorbent; make the slurry in the internal state of "curing". The compact structure is interface better aggregate and cement. So the selfcompacting lightweight aggregate concrete has better resistance to ion erosion performance.According to the same mixture preparative for SCLC35 and SCLC50 under the condition of standard curing, RCM method is used to testthe chloride ion diffusion coefficient of respectively age, its age includes 28 days, 84 days, 150 days, 210 days and 360 days. The results show that: Self-compacting lightweight aggregate concrete has good resistance to chloride ion diffusion coefficient; its resistance to chloride ion diffusion coefficient is far superior to ordinary concrete’s chloride ion diffusion coefficient. This is mainly due to the light aggregate around wrapped with a layer of dense structure of cement stone, Good interface between light aggregate and cement stone structure, The more homogeneous and elastic deformation more coordinated.Using scanning electron microscopy(sem) observe coarse aggregate, slurry and interface transition zone of self-compacting lightweight aggregate concrete, to observed its microstructure and interface properties, explore measures to improve interface performance. After molding, using micro hardness meter test cement matrix hardness. Test the light aggregate concrete the physical properties of each component. Research shows that: The porous structure of coarse aggregate has the water absorption and water features, aggregate and cement paste of hydration is more fully.Between aggregate and cement paste interfacial transition zone have no obvious boundaries. Coarse aggregate area minimum value of micro hardness, Coarse aggregate compressive strength is the weak areaof three-phase material.In general, using the globe shale ceramist as coarse aggregate, Add water, Thickener mixture of the raw materials and so on made from SCLC can satisfy the engineering application of the working performance and mechanical performance requirements. Self-compacting lightweight aggregate concrete has good ion erosion resistance and chloride ion diffusion coefficient. Coarse aggregate and cement paste can be hydrated adequately, no obvious interface transition zone, coarse aggregate strength is weak when the three-phase material compressive zone.