Experimental Research On Mechanical Properties And Frost Resistance Of Modified Rubber Recycled Concrete

Concrete is the most widely used and largest building material in the world at present,and it is an important part of the basic raw material industry of the national economy.Under the general trend of “green development”,higher demands are placed on the development of the concrete industry,not only to bear the energy conservation and emission reductions in its own development,but also to provide the material support for the national economy,the people's livelihood,and the construction of ecological civilization.Furthermore,It has great responsibility for the comprehensive utilization of solid waste and construction waste.Taking into account the requirements of contemporary national conditions for concrete,combined with the regional advantages of the pumice stone resources in the Inner Mongolia Autonomous Region,this paper disposeed of used construction waste as a coarse aggregate of concrete,using recycled coarse aggregate in whole or in part instead of natural pumice coarse aggregate.The waste tire rubber powder was used as a fine aggregate to make concrete and subjected to experimental research.In order to improve the problem of the decrease of concrete strength caused by the incorporation of rubber powder into concrete,the rubber powder used in this paper was modified rubber powder modified by two different surface modifiers.The experimental research was mainly divided into macroscopic tests and microscopic tests.Mechanical properties tests and rapid freeze-thaw cycle tests were set up in macroscopic tests.Stomatal analysis tests,ultra depth depth microscope tests,environmental scanning electron microscopes,and energy spectra analysis test were set in microscopic tests.Experimental study results are as follows:1.Through the surface modified rubber powder,not only the surface of the rubber powder becomes more flat and fluffy,but also the affinity of the rubber powder is enhanced,the wettability is improved,and the binding ability between the rubber powder and the cement paste is improved.2.The effects of modified rubber on the mechanical properties of recycled coarse aggregate concrete are as follows: when the number of modified rubber mesh is the same,the compressive strength decreases with the increase of the blending amount;when the blending amount of the rubber powder is constant,with the increase of mesh number,the compressive strength of concrete shows a tendency of increasing first and then decreasing,that is,the compressive strength of 80 mesh modified rubber concrete is the largest.3.In the correlation degree analysis of concrete strength,the orders of influence are obtained.When analyzing the effect of coarse aggregate on the strength of concrete,the spacing coefficient and the diameter of less than 100 ?m are the most important factors that affect the strength of concrete;when analyzing the impact of modified rubber mesh on the strength of all recycled coarse aggregate concrete,the specific surface area and pore diameter less than 100 ?m are the most important factors affecting the strength of the concrete;when analyzing the impact of modified rubber mesh on the strength of partially substituted recycled coarse aggregate concrete,the average chord length and the pore size of 100-200 ?m are the most important factors affecting the strength of the concrete.4.In the freeze-thaw cycle,the mesh number of the modified rubber powder has less influence on the freeze-thaw cycle of the concrete than the effect of the modified rubber powder on the freeze-thaw cycle of the concrete.When too much modified rubber powder is incorporated,the frost resistance of the recycled coarse aggregate concrete is unfavorable.5.Comprehensive mechanical properties and resistance to freezing and thawing cycle performance,it is advisable to use 80 mesh and 3% of modified rubber powder mixed into recycled coarse aggregate concrete.