Raw Materials of Dry-Mix Mortar

In recent years, with the acceleration of construction industrialization and the promotion of green building materials, dry-mix mortar has been 

increasingly widely used in construction projects. Compared with traditional site-mixed mortar, dry-mix mortar offers advantages such as stable 

quality, high construction efficiency, and reduced environmental impact. Its overall performance largely depends on the scientific formulation 

and quality control of raw materials.

I. Cementitious Materials: The Core of Strength Development

The foundation of dry-mix mortar lies in cementitious materials, primarily . Through hydration reactions, cement forms calcium silicate hydrate 

(C-S-H gel), which provides the main source of mechanical strength.

In addition, mineral admixtures such as fly ash and ground granulated blast furnace slag (GGBS) are widely used. These materials exhibit pozzolanic 

activity, improving long-term strength and durability while reducing overall costs. Gypsum is typically added to regulate setting time and ensure 

proper workability during application.

II. Aggregates: Influencing Structure and Workability

Aggregates serve as the skeletal structure and filling component in dry-mix mortar, commonly consisting of dried and graded sand such as quartz 

sand or river sand. Their particle size distribution plays a critical role in determining density, flowability, and resistance to segregation.

A well-designed grading system reduces porosity and increases bulk density, optimizing material usage and cost efficiency. In recent years, manufactured 

sand has gained popularity, although its irregular particle shape may affect rheological properties and often requires adjustment with additives.

III. Functional Admixtures: Key to Performance Control

Although used in small quantities, admixtures are essential for controlling the performance of dry-mix mortar. Among them, cellulose ethers such as (HPMC) 

and (MHEC) are the most critical.

Their main functions include:

Enhancing water retention

Improving workability

Regulating rheological behavior

Extending open time

In addition, redispersible polymer powder (RDP) forms a polymer film after dispersion in water, significantly improving adhesion strength and crack resistance. 

Other additives, such as water reducers, air-entraining agents, and starch ethers, further optimize construction performance and durability.

IV. Fillers and Modified Materials

Fillers such as calcium carbonate and talc powder are used to improve workability and reduce costs. In high-performance mortar systems, reinforcing materials 

like polypropylene (PP) fibers may also be added. These fibers create a “bridging effect,” enhancing crack resistance and mechanical stability.

V. Development Trends

With increasing standardization and sustainability requirements, dry-mix mortar raw materials are evolving toward low-carbon and high-performance solutions. 

On one hand, the use of industrial by-products is being expanded to reduce carbon emissions. On the other hand, advanced admixture technologies are enabling 

lower dosage and higher efficiency.

Overall, the raw material system of dry-mix mortar has shifted from a traditional approach to a more refined and functionalized system. In the future, continuous 

material innovation will further drive the industry toward high-quality and sustainable development.

Name: Cecilia.Wang

E-Mail:cecilia.wang@jtdf-rdp.com

Mobile:+86 190 3451 3486（Whatsapp）