| As the main cementitious material used in concrete,the problems of resource consumption,energy consumption and environmental pollution are very prominent in the production process of cement.The stone powder can replace the use of cement,has been widely used.The concrete mixed with stone powder has many problems,such as large shrinkage and easy cracking,which can be modified by fiber.However,the addition of stone powder and fiber will also affect the flowability,strength and other properties of concrete,and understand the performance control mechanism of cement-based materials with stone powder and fiber is very important for the further development of admixtures.In order to study the performance and influence mechanism of stone powder fiber mortar,this paper studies the single admixture of zeolite powder,talcum powder and polypropylene fiber,as well as the composite admixture of fiber-zeolite powder and fiber-talcum powder,and measures the flowability,cohessiveness,adhesiveness and strength of each mixture of mortar.The packing density of samples with different proportion is measured,and the water film thickness of each sample is calculated.The effects of water film thickness and porosity on mortar performance are explored and the conclusions are as follows:1.With the increase of zeolite powder content,the flowability of mortar would increased first and then decreased.When the content of zeolite powder is 5%,the flowability of mortar is the largest and the cohesiveness is the smallest.With the increase of water binder ratio,the adhesion would increased first and then decreased.The addition of zeolite powder will increase the porosity and decrease the strength of the test block.2.The addition of talcum powder can improve the flow spread and flow rate of mortar but reduce the cohesion and adhesion of mortar.With the increase of talc content,the porosity of the test block increases and the strength decreases.3.The addition of fiber can reduce the flowability of mortar.The cohesion of mortar increases with the increase of fiber content.The adhesion of mortar first increases and then decreases with the increase of water binder ratio.With the increase of fiber content,the porosity of the test block also increases and the strength would decreases first and then increases.4.When zeolite powder,talc powder and fiber are added separately,the packing density increases first and then decreases with the increase of the content of zeolite powder and talc powder.When the content of zeolite powder is 10%,and the content of talc powder is 15%,the packing density reaches the maximum value.The incorporation of fiber will lead to the decrease of packing density.5.The water film thickness can reflect the influence of admixture on packing density and specific surface area.When the three materials are mixed separately,the water film thickness is the fundamental control factor of the flowability and adhesiveness of mortar.The flow spread,flow rate,cohesiveness and adhesiveness of mortar depend on the water film thickness,and the amount of admixture also has influence.The flow rate and cohesiveness of the mixed fiber zeolites are almost entirely determined by the water film thickness.The flow spread is affected by the water film thickness and the amount of the fiber and zeolites content,while the relationship between water film thickness and the cohesiveness of the mortar is weak.The flow spread and cohesion of the composite fiber talcum mortar are affected by the water film thickness and fiber-zeolite content.The flow rate almost entirely depends on the water film thickness;the relationship between the thickness of water film and the compressive strength of the admixture mortar is weak,and the compressive strength is mainly affected by the porosity. |
