What Is Soil Cement?

Soil polymer cement is a new type of alkali activated cement. The main raw material is kaolinite-containing clay, which is calcined at 500 ~ 900 ° C and uniformly mixed with alkali salts and so on under a certain fineness.

Soil polymer cement is a new type of alkali activated cement. The main raw material is clay containing kaolinite, which is calcined at 500 ~ 900 ° C.

(1) Raw materials

Kaolin. Kaolin is the main raw material of geopolymer cement. The production of geopolymer cement does not require high purity of kaolin, and clays with low kaolinite content can also be used. Therefore, ordinary clays, such as red soils that are abundant in the south of China, can be used as raw materials for the production of geopolymer cement.

Alkali and alkali salt. Geopolymer cement can directly activate calcined clay with alkalis such as KOH and NaOH. Portland cement clinker is sometimes considered as an activator.

Mixed materials: Volcanic ash, highly active slag, fly ash, silica fume and other industrial waste slags can be used as geopolymer cement mixed materials.

Admixtures: admixtures mainly used to adjust the setting time of geopolymer cement, such as polyphosphate and metaphosphate.

(2) Process flow

Kaolinite-containing clay is added with water, mud, dehydration, drying, crushing, sintering, calcination (500 ~ 900 ° C), alkali salt (alkali), mixed materials, additives, grinding, and packaging. ^[1]

(1) Performance characteristics

Geopolymer cement is calcined at a relatively low temperature (500 ~ 900 ). Among them, amorphous silicon aluminum compounds such as metakaolin in a metastable state undergo the action of alkaline activators, and the silicon aluminum chain undergoes a depolymerization. To re-aggregation. Geopolymer cement has the following excellent properties. '

Low heat of hydration. Geopolymer cement is prepared at a lower temperature. Compared with ordinary portland cement, geopolymer cement has a small amount of "excess" energy and shows a low heat of hydration. The rapid temperature rise avoids the occurrence of looping thermal stress.

Small shrinkage. Geopolymer cement exhibits a completely different hydration mechanism from ordinary portland cement. After ordinary portland cement hydration, a large chemical shrinkage occurs, while geopolymer cement exhibits good volume stability after hydration. Shrinkage is much smaller than ordinary Portland cement.

Early strength is high. Like ordinary alkali-activated cement, geopolymer cement exhibits higher early strength. Hydration of geopolymer cement at 20 ° C for 4 hours, compressive strength can reach 15-20MPa; geopolymer cement concrete prepared with high-quality aggregate, At , the compressive strength of 1d can reach 56MPa; the later strength of geopolymer cement does not decrease. Under certain process conditions, the strength of geopolymer cement products can reach more than 300MPa. Therefore, geopolymer cement is also classified into the category of chemically bonded ceramics.

Good impermeability and freeze-thaw resistance. Geopolymer cement can form a dense structure with high strength and excellent impermeability, and the electrolyte concentration in the pore solution is high, so the ability to withstand freeze-thaw cycles is enhanced.

Resistant to chemical attack. Geopolymer cement does not produce sulfoaluminate minerals such as ettringite when hydrated, so it is resistant to sulfate attack. Geopolymer cement shows good stability in acid solutions and various organic solvents.

Good high temperature resistance. Geopolymer cement has a melting point of about 1250 ° C, which shows good high-temperature mechanical strength, and its fire and heat resistance is far superior to ordinary portland cement.

Resistant to water and heat. Under hydrothermal conditions, ordinary portland cement is more susceptible to destructive damage, while geopolymer cement can maintain better stability.

It can adjust temperature and humidity automatically. Under natural conditions, when the outside temperature is low, the soil poly cement can absorb moisture in the air. When the external temperature rises, the water absorbed by the soil poly cement evaporates, forming a more stable temperature and humidity condition inside the soil poly cement seal structure. Eliminates the phenomenon of resurgence on the inner surface.

Excellent durability. ^[1]