| The application of Super Absorbent Polymer(SAP)in concrete project is an important engineering technology innovation,of which the relative research has just started out both in China and abroad.There are still a lot of gaps to fill in around this area.This project's research work started from relative main performance of concrete with SAP and expands its application in green construction.A detailed study focused on the uncertain change of compressive strength that was a concrete mechanical performance of concrete with SAP was conducted in this paper.Through the combination of multi aggregate size,several additive amount and different water cement ratio,a comprehensive analysis and discussion on the characteristics of concrete compressive strength and related factors were carried out.The research shows that,additive amount and aggregate size have influence on concrete mechanical performance.Aggregate size has a strong influence on concrete strength at early stage of concrete development.Larger size of aggregate is easier to increase concrete strength at early stage.The best general effect appears when additive amount is 0.2% and the aggregate size is 30-50 meshes.The microscopic structure characteristics of concrete with SAP is analysed qualitatively and quantitatively through combined methods of MIP,SEP,image pro,to study the influence of super absorbent polymer on concrete relevant performance.The study shows that SAP amount and aggregate size have great influence on micro performance index of concrete.Porosity,average pore diameter and coefficient of pore average diameter have varying degrees of increase.The porosities of 10?m~200?m and 200?m~800?m have a high dependency with strength of concrete with SAP.High water cement ratio and small aggregate size increase the porosity of 10?m~200?m level.High water cement ratio and large aggregate size have great influence on pore of 200?m~800?m level,therefore pore diameter smaller than 800?m should be strictly controlled.The principles of SAP application are: low water cement ratio,large aggregate size and low additive amount.Radial basis function(RBF)neural network was used to quantitative analyzes the correlation between sample strength and pore structural feature.The quantitative formula of strength and pore structural feature is established and the importance ranking of grading void ratio and porosity are: 10?m~200?m?200?m~800?m?>1?m?0.1~1?m?<0.1?m?800?m~1600?m.In this paper,the hydration reaction of concrete with SAP was studied in detail.The positive role of water absorbent polymer in concrete hydration reaction was proved by the method of macromolecular chemical thermal analysis.The new method was put forward to explain the principle of SAP.It shows that the addition of SAP is beneficial to the production of CH.As SAP goes into concrete gelatin system,it influences the amount of hydration products as well as its hydration process.The hydration reaction of the cement is effectively promoted by the unique spatial network structure of SAP gel solution and the Ion exchange of the hydrophilic group,as well as the interlocking of.The mechanism of permeability for concrete with SAP was conducted through the method combined with permeability and microstructure of super absorbent polymer.The research shows that SAP can effectively improve the anti-permeability performance of concrete.SAP changes the internal pore connectivity.It improves the resistance value of pore by reducing the capillary pressure and changing the shape of pores;SAP forms a "threshold effect" inside the concrete to increase the fluid flow resistance.New application of concrete with super absorbent polymer in green construction combined with green construction concept was presented conceptually in this paper,with a preliminary experimental verification.The construction materials and environmental protection were carefully combined to open up a new field in the application of concrete with SAP. |
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