The Research On Activation, Solidity Of Silt In The Yellow River And Preparation Of Clay-based Cementitious Material

The Yellow River silt is a kind of sedimentary sandy soil which formed because of slow deposition gradually when the Yellow River flows through the loess plateau carry large amounts of sediment to the Lower Yellow River. These poor soil is unfit for plants growing, and unfit building materials for its low strength, poor water resistance and low activity, so its application was limited. With the support of the National Natural Science Foundation of "Physical and mechanical properties of degradable clay-based cementitious materials" financial aid, the research on activation, solidity of silt in the Yellow River based on the investigation and analysis of the beach area of the lower reaches of Yellow River silt characteristics have been achieved, on the other hand through activation and fixation, preparation.the clay-based cementitious material, according to local conditions to develop new building materials have been done. All of these works will be helpful to the socialist type rural construction process of building a socialist-based rural energy saving, insulation, new green walls material needs. In this paper, the main research contents and results include following:1 Through four areas of the Lower Yellow River silt investigation and analysis, the constitution and physical status of soil is clearly as follows:Most of particles are powdery, colloidal activity is poor and contain little organic matter, pH is slightly alkaline, and chemical and mineralogical analysis showed that the soil contains too much silica, which cause the activity is very low. The microeconomic display the Yellow River water long-range transport as the role of rounded particles is high and surface strength is low.2 To use sodium hexametaphosphate, calcium chloride and sodium silicate as an activator can significantly enhance soil's activity, adhesion stress and water-resistance:Sodium hexametaphosphate, calcium chloride and sodium silicate can activate the soil effectively. As the experiment shows, samples composed of soil added into 2% activator compressive strength can be increased by 16% than it composed of pure soil. And with the activator content increases, the strength continues to grow, water is also greatly improved. The infrared and microcosmic analysis shows that activator can change the soil particles surface hydroxyl groups, and silicate minerals and soil reaction in the calcium silicate gel, which distributed around the soil particles, cemented soil.3 The clay-based cementitious material which activated by sodium hexametaphosphate, calcium chloride, sodium silicate have favorable mechanical and physical properties, especially favorable water-resistance:As the experiment shows, the clay-based cementitious material which activated by sodium hexametaphosphate, calcium chloride, sodium silicate and. mixed with lime, cement and fly ash have a good performance:incorporation of 4% activator 28d compressive strength of the specimens was 20.8MPa, and the softening coefficient was 0.76, which good durability and strength of continued growth in the late, can greatly increase their range of applications.