A kind of dry powder mortar and its admixture

Abstract

The invention discloses dry-mixed mortar and an additive thereof. The dry-mixed mortar additive comprises an inorganic thickening agent which is a mixture of lamelleted metakaolin and granular expanded vermiculite powder in a weight ratio of (20:80) to (80:-20); the metakaolin is metakaolin having the size being less than 1250 meshes; the expanded vermiculite powder is expanded vermiculite powder being less than 325 meshes. After the above two components are compounded in a certain ratio, the crushing rate of the expanded vermiculite powder is reduced because of the lamelleted metakaolin, and the water release and mortar separation caused by crushing of the expanded vermiculite powder are inhibited, and thus the stable thixotropy of the mortar is maintained; on the other hand, due to adoption of the expanded vermiculite powder, the pH value of the mortar is buffered, a stable activating agent is provided for metakaolin, and the water retaining property of metakaolin is improved; due to graduation of the lamelleted and granular thickening agent and the bonding effect of multiple ligating atoms, a relatively large hydrogel network is formed, the thixotropy of mortar is improved, and the construction compatibility of mortar is ensured.

Description

Technical field [0001] The invention relates to building materials, in particular to a dry powder mortar and its admixture. Background technique [0002] Dry mortar refers to a granular or powdery material that is physically mixed in a certain proportion of aggregates such as quartz sand, inorganic cementing materials such as cement, and additives such as polymers that have been dried and screened; It is transported to the construction site in the form of bags or bulk, and can be used directly after adding water and mixing. It is also called dry powder, dry mix, and dry mix. Some construction adhesives also belong to this category. Dry mortar is used as a thin layer to play the role of bonding, liner, protection and decoration in the construction industry, and it is widely used in construction and decoration projects. [0003] The main performance indicators of mortar include strength and construction and workability. Among them, strength mainly refers to the compressive strength...

AI Technical Summary

Problems solved by technology

Among them, metakaolin is formed by dehydration of kaolin at an appropriate temperature. It has high compression resistance, but its water retention is caused by the irregular molecular arrangement in the thermodynamic metastable state. Improve the overall compressive strength of the mortar

In contrast, vermiculite powder has high water retention, can promote cement hydration, and is beneficial to improve the overall compressive strength of mortar, but its own compressive resistance is poor, but the granular inorganic thixotropic agent is easy to Squeezed and broken, the moisture absorbed in it is released, resulting in segregation of the slurry, and a sudden change in the thixotropy of the mortar, resulting in a great influence on the performance of the slurry with its added amount.