New Lightweight Aggregate Concrete Based Alkali - Aluminum Silicate Cementitious Materials, Meso-damage Studies

At present, both normal concrete or lightweight aggregate concrete, mostly using cement as cementitious materials, known that the cement in the production process produce large amounts of carbon dioxide, sulfide, hydride, and other harmful gases, environmental pollution is serious, our research group developed a new type of cementitious material——based on aluminum-silicate cementitious materials, it has high strength, strong acid corrosion, good high-temperature insulation, good fast hard curing performance and lower energy consumption, is a new type of green environmental protection cementitious materials,based on alkali-silicate cementitious materials,we prepared a kind of concrete which has lightweight,high strength,good durability,good performance with lightweight aggregate. In this paper,we study the lightweight aggregate concrete based on alkali-silicate cementitious materials from the microscopic point of view.On meso-level, lightweight aggregate concrete is taken as three-phase composites consisting of mortar matrix,lightweight aggregate and the bond between matrix and aggregate.Based on the analysis of microstructure of lightweight aggregate concrete generate,achieve circular aggregate,oval-shaped aggregate,pentagon aggregate three types of aggregate random distribution,then using the finite element analysis software ANSYS to mesh the geometric model.Based on the graphical interface secondary development language UIDL which provided by ANSYS software,customed user graphical interface of this lightweight aggregate concrete damage numerical analysis. Then based on random distribution of interior in alkali-silicate cementitious material lightweight aggregate concrete,the meso-damage constitutive model of a new lightweight aggregate concrete material is derived by using the microscopic damage mechanics.Then through self-designed program realization coupling damage to simulate the damage process of lightweight aggregate concret,analysis the influence law of macroscopic strength of mechanical parameters of each phase homogeneous degree,lightweight aggregate content,lightweight aggregate shape and size of lightweight aggregate concrete specimen. And then test the feasibility of this numerical simulation through the lightweight concrete under uniaxial compression stress-strain curve experiment.