Analysis of the Destruction Kinetics of Nanomodified High-Strength LightweightConcrete by Acoustic Emission
The paper presents the experimental data and analysis of the dependence of energy of acoustic emission on the physical and mechanical properties of high-strength lightweight concretefilled hollow ceramic microspheres. Shown that the kinetics of acoustic emission energy of the studied concrete can be described in three stages with different intensity and duration.The introduction of hollow ceramic microspheres into fine-grained sand concrete up to some limit (not more than 18% by weight) allows the formation of composite structure withlonger «safety stage», when acoustic emission energy varies with the lowest intensity at increasing the load. The duration of this stage depends on the mechanical properties of lightweightaggregate, cement-mineral matrix and strength of their mutual coupling. The hardening of the phase boundary between the filler and cement-mineral matrix will reduce the defectivenessof the structure of high-strength lightweight concrete with high content of hollow microspheres. Analysis of the destruction of high-strength lightweight concrete by the acousticemission method allows to determine the dependences of structure conversion when using nanoscale modifier and identify the limit of the formation the conditions for the smallestdefects in material. Shown that the greatest effect of the application of nanomodifier is observes for the compositions with average density less than 1500 kg/m3. It is expressed as anincrease in the relative change in the compressive strength and the changing the nature of the recorded parameters of acoustic emission. The acoustic emission method is an effectivemethod to study the influence of nanoscale additives on the structure and properties of construction materials.