Silicon powder cement show up thermal peak is slightly earlier than cement without silicon powder

With the silicon powder content increased, its efficiency index gradually decreased, when the silicon powder dosage> 20%, the efficiency index was significantly decreased, while > 30%, the strength of the concrete Flocking Machine may even decline. The so-called efficiency index is the replacement of cement with silicon powder, the contribution of 1 part silicon powder to concrete strength may be equivalent to 2 to 5 times strength of cement can be produced, the multiple is called the efficiency index of the silicon powder.

At the same time, the price of silicon powder is higher than cement, to meet the design strength of concrete or other performance requirements under the premise, with less doped is appropriately, in high-performance concrete, the usual dosage is generally between 5%-15%. Silicon powder instead of cement can reduce the heat of hydration temperature rise. Therefore, the dosage is usually less than 20%. However, due to the water consumption increased, to offset part of the strength growth. Make the grout and aggregate interfacial transition zone improved, and make pore structure refinement are caused the intensity increased.

Silicon powder cement show up thermal peak is slightly earlier than cement without silicon powder, but the total heat release below the cement without silicon powder.mhcmp. Silicon powder concrete increases the risk of plastic shrinkage cracking, especially in the higher evaporation rate. After adding silicon powder, about the silicon powder concrete strength increased degree is available to measure by efficiency index.

When larger slump, vibration time is relatively long, silicon powder concrete is not easy to segregate.

Thus, the general water consumption should increase with the silicon powder content increased. To improve the workability in cement consumption <300 kg/rn2, adding silicon powder can improve its cohesiveness, reduce the secretion of water. In order to reduce the early dry shrinkage of silicon powder concrete, can extend the moist curing time, dubbed the silicon powder slurry agent or incorporated into the appropriate expansion agent and so on. Reduce the air content: due to the specific surface area of the silicon powder is higher, in the case of the same dose air entraining agent, the gas containing should be reduced, although use superplasticizer will be the same.

Silicon powder concrete shrinkage and autogenous shrinkage increased by water-cement ratio reduce. Because the specific surface area of the silicon powder is very large, many of the free water in the fresh concrete are bound by silicon powder particles, can greatly reduce the secretion of water. When silicon powder dosage is too high, the fresh concrete become very viscous increase the construction pouring difficulty.

In the case of no superplasticizer also can delay the setting time, especially in case of high content of silicon powder. Reducing the accumulation of moisture in the interface, improve the interfacial bonding properties. When adding silicon powder to improve the strength of concrete, the difference of additives, the setting time is different, and some of them shortening for 1-2 h, some did not increase significantly, some delay for 2 h. General silicon powder concrete perform that drying shrinkage increases in early stage and reduce in later stage. But in order to maintain the same liquidity, while adding silicon powder are generally required to join superplasticizer. Plastic shrinkage cracking can occur in the concrete pouring until plastering start to solidify, occurs mostly in the concrete close to the initial setting. In order to prevent the plastic cracking, the concrete must be covered to prevent rapid evaporation surface covering the available sacks or plastic film or the curing agent, or use the spray method to reduce evaporation, some can retard evaporation special admixtures, also be used to reduce plastic shrinkage cracking danger.