Experimental Study Of Sulfate Attack Of High-performance Concrete With Compound Mineral Admixture

Xinjiang is an arid and saline region with saline land area of about 26% of the total area of Xinjiang. These regions contain very high sulphate in soil and groundwater, and magnesium salt is also contained. Thus the concentration of sulfuric acid root ion(SO42-) is as high as 10000 mg/L(or more than 10000 mg/kg), some even can reach above 30000 mg/L. Therefore, sulfate erosion is a big harm in the concrete engineering construction in Xinjiang. Sulfate erosion is the biggest and most erosion and also it is an important factor affecting the durability of concrete. The sulfate attack resistance can be effectively improved by low water/cement ratio, mixing with high efficiency water reducing agent and high performance concrete mixed with large quantity of superfine admixture. Using high performance concrete double mixed with ? grade fly ash, slag powder and YK- ?, a high durability concrete mineral admixture, but reducing the amount of cement, could strengthen particle filling effect and secondary hydration effect(also called volcano ash effect) of superfine admixture in cement concrete, and could greatly improve the compactness of concrete and microstructure of the concrete aggregate and cement interface, so as to further improve the strength, impermeability and corrosion resistance of concrete. Meanwhile, synergies of the admixture with large dosage of superfine admixture like fly ash and slag powder added in high performance concrete could effectively absorb internal components [Ca(OH) 2] in cement stone that easily be eroded by erosion medium like sulphate, magnesium salt, acid and soft water. The synergies could also greatly improve erosion resistance and the early strength of concrete, and make up the shortage and negative effects of early low strength of concrete caused by mixing large dosage of the superfine admixture, especially fly ash. This test results will provide quantificating sulfate attack resistance of high-performance concrete and the new technology of resistance to sulfate erosion in this region with adequate scientific basis.