Experimental Study On Mechanical Properties And Frost Resistance Of Modified Coal Gangue Aggregate Concrete

In order to further improve the resource utilization rate of coal gangue,the related experimental study was conducted,the modification method of Ganggue aggregate concrete was explored,and the effect of steel fiber type and mineral admixture on mechanical properties and antifreeze performance of gangue concrete was mainly carried out,which provide the technical support for the application of gangue concrete in cold area.The main research contents are as follows:(1)The mixing ratio optimization experiment was carried out,under the same particle size the influences of different grain types on the concrete strength were compared.The experimental results show texcellent concrete can be find by the reasonable blending of crushed coal gangue coarse aggregate and round coal gangue ceramic sand,and the compressive strength can reach 53.02 MPa.(2)The experimental study on the frost resistance of coal gangue aggregate concrete was carried out.The effect of coal gangue coarse aggregate on the frost resistance was compared.It was concluded that the anti-freeze-thaw cycle number of coal gangue aggregate concrete with round coal gangue as coarse aggregate is only 200 times,the concrete freeze-thaw cycle number of concrete with crushed coal gangue aggregate can be up to 500 times.So the coarse aggregate of crushed coal gangue can improve the frost resistance of coal gangue aggregate concrete obviously.(3)The mechanical experiments of coal gangue aggregate concrete with crushed stone gangue as coarse aggregate and steel fiber were carried out in this paper,the mechanical properties effect of steel type and content were compared.The experimental results showed that the splitting tensile strength increased 75.1% as the blended steel fiber content increased 1%,and the flexural strength increased about 140.8%,which can meet the construction performance of concrete mixture.(4)The effects of the frost resistance of coal gangue aggregate concrete about steel fiber type and steel fiber content were studied by rapid freezing and thawing experiment.The results showed that the reasonable fiber content could increase the corrosion resistance and wave steel fiber had obvious advantages to reduce the loss of freezing and thawing strength.Rapid freezing and thawing experiments of the coal waste aggregate concrete replaced with different proportion of slag indicates showed the slag had no effect on the strength and freeze-thaw resistance of coal gangue aggregate concrete.(5)The effect of Copper-coated steel fiber and end-hook steel fiber content and s-ubstitution rate on pore structure of coal gangue aggregate concrete were analyzed by r apid air concrete stomata analyzer.The results show that: The coal gangue aggregate concrete that the hook-type steel fiber was put in has a significant effect on its internal structure.It will make the number of concrete bubbles increases,the specific surface area of the bubble increases,the bubble pitch coefficient decreases,and the average chord length of the bubble decreases.Namely,the internal structure of concrete will to get the direction of small pore that will benefit the frost resistance.