Effect of Rubber Powder on Durability of Cement-based Materials


Release time:

2021-10-11

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Effect of Rubber Powder on Durability of Cement-based Materials

Effect of Rubber Powder on Durability of Cement-based Materials


The formation of polymer continuous film is extremely important to the performance of polymer modified cement mortar. In the process of setting and hardening of cement paste, many cavities will be produced inside, which will become the weak part of cement paste. After the re-dispersible emulsion powder is added, the emulsion powder is immediately dispersed into an emulsion when exposed to water and gathers in the water-rich area (I. e., in the cavity). With the setting and hardening of cement paste, the movement of polymer particles is more and more restricted, and the interfacial tension between water and air will promote them to gradually arrange together. When the polymer particles come into contact with each other, the network-like water evaporates through the capillary, and the polymer forms a continuous film around the cavity, strengthening these weak areas. At this time, the polymer film can not only play a hydrophobic role, but also will not block the capillary, so that the material has good hydrophobicity and air permeability.


The cement mortar without polymer is very loosely connected, on the contrary, the polymer modified cement mortar makes the whole mortar very tightly connected due to the presence of the polymer film, thus obtaining better mechanical properties and weather resistance. Latex powder modified cement mortar, latex powder will increase the porosity of the cement paste, but reduce the porosity of the interface between the cement paste and aggregate transition zone, resulting in the overall porosity of the mortar is basically unchanged. Latex powder after film formation can well block the pores in the mortar, making the cement paste and aggregate interface transition zone structure more compact, latex powder modified mortar permeability improved, enhance the ability to resist the erosion of harmful media, so as to improve the durability of the mortar have a positive effect.
 

Key words:

Rubber powder