The Feasibility Study Of The Application Of The Ground Natural Volcanic Ash In Cement Concrete In The Region Of Hotan Xinjiang

The pozzolanic material with the character of activity is one of the most essential components in the preparation of HPC which has great benefits to control aggregate alkali activity, improve the ability of resistance to sulfate erosion and enhance the durability of concrete. However, the region of Hotan Xinjiang is lack of artificial pozzolanic materials such as fly ash, and long-distance transport greatly increases the cost of engineering construction. At the same time, the region has rich natural volcanic ash resources, so the research of the feasibility of grinding fine natural volcanic ash used in cement concrete has very important significance to reduce engineering cost and improve concrete performance. The thesis conducts a feasibility experiment aimed at whether the grinding fine natural volcanic ash can be the concrete admixture in the region of Hotan Xinjiang. The main research results include the following aspects:(1) The test research shows that grinding fine natural volcanic ash technical indexes are accorded with the standard requirement of JG/T 315-2011 and DL/T 315-2012.(2) Based on the XRD and SEM, it has been proved that the volcanic ash-cement composite gel system and the hydration products and Portland cement gel system have the similar main hydration products, but the former’s hydration reaction is slower and the structure of hydration products are more loose with many pores.(3) The grinding fine natural volcanic ash has certain pozzolanic activity and the trend of gradually increasing the strength of cement mortar specimen mixed with different admixture amounts or combination with coal ash mixed in the cement mortar.(4) The grinding fine natural volcanic ash has inhibitory effect on aggregate alkali activity, its inhibitory effect increases with the increase of admixture amount.(5) The compressive strength of volcanic ash concrete is slightly lower than the fly ash concrete under the same water-binder ratio, but the design requirements can be meet by appropriate mixing ratio.(6) The volcanic ash concrete has the anti-carbonation capability, but its antifreeze performance and inhibiting sulfate erosion ability is weak.