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In this paper, the effects of citric acid (CA) and protein retarder (SC) on the properties of phosphogypsumsulfoaluminate cement composite cementitious system were investigated. The fluidity, setting time and compressive strength were tested to evaluate the workability and mechanical of composite system, and the change of conductivity, phase composition and microstructure were analyzed to clarify the influence mechanism of different retarders. The results show that the strength loss of composite cementitious system under the action of SC is smaller than that of CA when the same setting time is achieved. The addition of two retarders has a certain inhibitory effect on the dissolution of composite system during the hydration induction and the acceleration period, and CA has a greater inhibitory effect than SC at the same content. CA can cause gypsum dihydrate crystals to show a flat and coarse structure, which has a greater impact on the mechanical properties, while SC increases the overall scale of gypsum dihydrate crystals, with little change in crystal morphology, which has a smaller effect on the deterioration of the mechanical properties of composite system. [ABSTRACT FROM AUTHOR]

The treatment methods of asphalt pavement diseases, and the preparation and testing methods of modified asphalt crack paste specimens are introduced. The impact of plasticiser, modifier, tackifier and padding on softening point, low temperature flexibility, peel strength, shear strength and continuous cohesiveness of asphalt/crack paste are discussed respectively, and the results showed that, the addition of plasticizer could improve the performance of asphalt/crack paste. Then a suitable material ratio was obtained in combination of environmental protection and the cost, and the performance of the crack paste prepared according to this ratio were tested. [ABSTRACT FROM AUTHOR]

The relationship between the government and market is, in nature, the issue of two kinds of orders. Under the impact of economic globalization and financial crisis, the fundamental issue of the reorganization and economic transformation of domestic steel enterprises is that of in-time transformation of governmental governance model and role. The essential pathway of the reorganization of steel enterprises and transformation of economic structure is achieved through the transformation of governmental governance in the following aspects: changing the model of governmental governance from administrative intervention in economic operation to limited, accountable and rule-of-law modern governance, establishing fair and just rules, improving systems of property rights, modern enterprise and the accountability of government investment projects, continuing to exert macroeconomic control and to press the government to quit fields of ordinary market competition, overcoming administrative monopoly and regional protectionism and advancing the standardization and perfection of the market order. [ABSTRACT FROM AUTHOR]