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Microfiller effect on rheology, microstructure, and mechanical properties of high-performance concrete.

Superplasticizer in concrete 2021-09-03 12:42 124
The purpose of this study is to have a basic understanding of the micro filler effect in high performance concrete.; Using coaxial cylinder viscometer and micro slump test, marsh studied the potential mechanism of micro filler effect convective rheology in cement slurry. Cone flow time and pressure discharge test. They were also studied in mortar using ASTM flow meter test, and in concrete using computer-controlled rheometer, slump test, conventional slump test and induced leakage test. It is found that micro fillers improve the efficiency of superplasticizers because they increase surface water and reduce bulk water by reducing the void space in the particle mixture. Ultrafine particles also reduce the exudation water, thus reducing the appearance of low-density microstructure characteristics at the exudation channel and interface. It is also proved that the three admixture cement containing pozzolanic and non pozzolanic filler can achieve excellent rheological properties. In the early and late stage, the effects of micro fillers in mortar and concrete on mechanical properties were studied. It has been found that this effect depends on the initial porosity of the system. Therefore, replacing up to 15% of cement with non cementitious filler will lead to a significant increase in strength. This is more significant in the three admixture cement containing the combination of pozzolanic and non pozzolanic filler. For these cements, the proportion of partially replacing cement as high as 30% will lead to a significant increase in strength; The early strength of ultrafine carbonate filler is increased by about an order of magnitude. Because some micro fillers seem to preferentially present the matrix for calcium hydroxide germination and growth in energy. Removing calcium ions from the solution can catalyze the dissolution of C; Quantitative image analysis of backscatter electron micrograph was used to quantify the effect of micro filler on the microstructure of high performance concrete. Cement slurry and concrete were analyzed on days 1 and 28. This technique confirmed the acceleration of hydration reaction caused by carbonate micro filler in the early stage. Micro fillers usually reduce porosity and improve their microstructure characteristics.; The micro filler effect in high performance concrete is studied from the perspective of particle filling theory. Deeply understand the particle accumulation model, the effect of particle accumulation on rheology and the effect of particle size distribution on hydration reaction. On the basis of estimating the effect of filling density and micro filler on hydration rate, a new parameter, micro filler efficiency factor, was developed. It is found that there is a close correlation between micro filler efficiency factor and compressive strength. In addition, a new model connecting microstructure and strength is proposed. The model proposed in this paper considers the quantitative values representing the properties of hydration products for the first time to help estimate the strength( Expand ▼
Tag:Microfiller,effect,rheology,mi