Experimental Study On Preparation Of Underwater Non Dispersive Steel Fiber Reinforced Concrete Based On Rheological Properties

In order to prepare the underwater non-dispersive steel fiber concrete with good working performance,anti-dispersive performance and mechanical properties,this paper takes into account the flocculant content,water reducing agent content and sand dosage,and conducts tests on the rheological properties of the clean slurry and mortar.Based on the rheological properties of the slurry,by changing the steel fiber and flocculant content,Its influence on the working performance,rheological properties,anti-dispersion properties and mechanical properties of underwater non-dispersing concrete was investigated.The main research contents and relevant conclusions are as follows:(1)Change the dosage of flocculants and water reducing agent dosage,studies its influence on net slurry rheological properties,and the Herschel--Bulkley model was carried out on the net slurry rheological curve fitting,each net slurry rheological equation is obtained,and the rheological parameters.The results showed that the fluidity of the slurry first increased and then decreased with the increase of flocculant dosage.The yield stress and consistency decrease first and then increase.Increasing viscosity and thixotropy;The fluidity increases with the increase of water reducing agent content.Yield stress and consistency decrease gradually.Viscosity and thixotropy also decrease.(2)Change the flocculant dosage,and sand dosage,dosage of water reducing agent and to study its influence on mortar rheological properties,and each group is obtained by fitting the slurry rheological equation and rheological parameter.The results show that the fluidity of mortar first increases and then decreases with the increase of flocculant content.The yield stress and consistency showed an upward trend.Increasing viscosity and thixotropy;With the increase of water-reducing agent content,the fluidity first increases and then remains unchanged.The yield stress,consistency and viscosity decreased.Thixotropy decreases continuously;With the increase of sand consumption,the fluidity decreases and the yield stress,consistency,viscosity and thixotropy increase.The rheological relation between slurry and mortar is deduced by the formula.(3)Change the dosage of flocculant and steel fiber content,the working performance of concrete is studied,the influence of the rheological properties and dispersion resistance properties,the results showed that the dosage of flocculant and the increase of steel fiber content,yield stress and plastic viscosity of concrete mixing and T500 is on the rise,and scattered resistance increased,The expansion degree,J ring expansion degree and segregation rate showed a decreasing trend.In addition to S0.8-A1.5,the slump expansion degree of other groups of concrete prepared in this experiment is above 550 mm and the segregation rate is below 15%.(4)Change the flocculant dosage and steel fiber content,studied the influences on the mechanical behavior of concrete,the results showed that the dosage of flocculant and the increase of steel fiber content,the cube compressive strength of concrete presents a trend of decrease the first increases.The splitting tensile strength increased with the increase of steel fiber content,but when the steel fiber content reached 1.2%,the tensile strength of the sample with 1.5% flocculant content decreased slightly.With the increase of flocculant dosage,the tensile strength decreased at 7d and increased at 28 d.In addition,the 7d water-land compressive strength ratio of the underwater pouring group is above 0.6,the 28 d water-land compressive strength ratio is above 0.8,the 7d water-land tensile strength ratio is above 0.6,and the 28 d water-land tensile strength ratio is above 0.65,meeting the requirements of the code.