Preparation Of Ultra High Performance Concrete By Aeolian Sand And Its Properties

Ultra-high performance concrete is a kind of concrete with high strength,high durability and high toughness.Aggregate is an important factor affecting its performance.The selection of aggregate,in addition to the need to meet the technical indicators,but also must be economical.Eolian sand is a kind of good building material,which not only meets certain technical indexes,but also has excellent economy because of its large reserves.In this paper,the influence of various factors on the working performance and mechanical properties of aeolian sand ultra-high performance concrete is explored through fluidity test,concrete gas content measurement test,concrete compressive test,concrete flexural test and so on.Then further test,select each kind of admixture and admixture material the best dosage,get the best mix ratio;Finally,under this mix ratio,quartz sand UHPC is compared to comprehensively explore the mechanical properties and durability of eolian sand UHPC,and conduct benefit analysis.The research conclusions are as follows:(1)Adding a certain amount of silica fume powder to aeolian sand concrete can improve the workability of the mixture and enhance the strength of concrete;Adding proper amount of superplasticizer can reduce the water-cement ratio and improve the fluidity of the mixture.Adding proper amount of concrete defoaming agent can reduce the air content of concrete and improve the compressive strength of concrete.The mechanical strength of concrete can be improved by adding proper amount of fiber material.(2)The orthogonal experiment was designed,and the range and variance analysis were carried out to explore the optimal mixing amount of steel fiber,basalt fiber,silica fume and defoaming agent.The final test results show that when the volume content of steel fiber 2.5%,basalt fiber 1.5%,silica fume 10% and concrete defoaming agent 0.28%,the UHPC has the best working performance and mechanical strength.(3)Test was carried out according to the optimal mix ratio to explore the differences in mechanical properties and durability between UHPC of aeolian sand and UHPC of quartz sand.The test results show that under the condition of steam curing,UHPC prepared by aeolian sand can achieve the compressive strength of more than 120 MPa for 7 days,the flexural strength of more than 20 MPa for 7 days,and the strength of more than F500 freeze-thaw cycles for 28 days,and has excellent frost resistance.(4)Compared with other aggregates such as river sand,quartz sand and gravel sand,the preparation of UHPC by aeolian sand in Northwest China has better economic and environmental benefits,and has been applied in many aspects of military engineering and civil projects.