Experimental Study On Mechanical Properties Of Rape Straw Fiber Fly Ash Concrete

Rapeseed straw is a renewable resource with rich fibrous tissue on its surface and wooden parts,which can provide high toughness and tensile strength.It has essential research significance in developing green and renewable building materials.To effectively reuse rapeseed straw and fly ash,this article adopts an orthogonal experimental analysis method to study the influence of fly ash(FA)content,rapeseed straw fiber(RSF)length range and RSF volume content on the mechanical properties and microstructure of rapeseed straw fiber reinforced concrete(RFC).The results of orthogonal experimental analysis indicate that the FA content is 10-15%,the RSF length range is 20-40 mm,and the RSF volume content is 0.1-0.2%,the mechanical properties of RFC can be effectively improved.The influence of FA dosage(a),RSF length interval(b),and RSF volume dosage(c)on the cube compressive and splitting tensile strength of RFC specimens is as follows: a > b > c;The degree of impact on flexural strength is: c > a > b;The degree of influence on the energy consumption difference of damage and initial crack impact is: b > c > a.The optimal level group for improving the cube compressive strength,flexural strength,and impact resistance of RFC specimens is FA dosage of 15%,RSF length range of 30-40 mm,and volume dosage of0.2%;The optimal level group for improving the splitting tensile strength of RFC specimens is FA dosage of 15%,RSF length range of 30-40 mm,and volume dosage of0.1%.The results of the specimen failure morphology indicate that the FA content is 15%,the RSF length range is 30-40 mm,and the RSF volume content is 0.2%,it can effectively suppress the brittle failure of RFC specimens under stress loads such as compression,tension,and bending,further improving the ductility performance of samples under static and dynamic loads.By fitting the Weibull model,it is verified that there is a linear correlation between the number of impact resistance times of the specimen.Microstructure analysis indicates that the addition of 15% FA can increase the rate of hydration reaction,promote the increase of hydration products,and improve the compactness of RFC specimens;RSF with a length range of 30-40 mm can suppress crack propagation and cracking;RSF with a volume fraction of 0.2% can be uniformly and randomly distributed within the matrix,presenting a three-dimensional mesh support structure,dispersing the stress generated by external loads,effectively alleviating stress concentration,and further improving the mechanical properties of RFC specimens.Figure [22] Table [19] References [96]...