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The existence of a large number of solid wastes has caused great pollution to the environment. In this study, different solid waste such as steel slag, water-quenched manganese slag, red mud and coal gangue was used in cement mortar, and the mechanical properties and hydration products were studied. Results showed that water-quenched manganese slag and high-calcium coal gangue after spontaneous combustion showed higher activity. Coal gangue has the highest activity of 102% and red mud has the lowest activity of 69%. Both steel slag and manganese slag added samples showed higher strength than that of manganese slag and steel slag separately added samples. The composite admixture of steel slag, manganese slag, red mud and coal gangue showed the highest strength at 7%, 8%, 8%, 7% and 7%, 12%, 4%, and 7%, respectively.

In order to enhance the large-scale and high-quality application of limestone powder (LP) and phosphogypsum in the construction industry. Therefore, this paper mainly studies the effect of LP on the physical and mechanical properties of phosphogypsum-based composites, and clear the mechanism of action from the micro level. Based on the results, the conclusions were as follows: LP has the effect of reducing the standard consistency water requirement and shortening the setting time of fresh phosphogypsum-based composites slurry; LP can increase the bulk density and reduce 24-hour water absorption of hardened phosphogypsum-based composites matrix; In addition, the strength of the matrix increases first and then decreases with the increase in the amount of LP and the recommended amount of LP is 5%-10%. Microscopic tests have shown that when the amount of LP is less than 10%, it can effectively reduce the porosity, refine the pore size, and play the role of a dense hardened matrix. In addition, the appropriate amount of LP particles can be adsorbed on the surface of dihydrate crystals, increasing the bonding force between the crystals, which is conducive to increasing the strength of the composite matrix.

The ultra-high toughness cementitious composites (UHTCC) was modified by different types of epoxy emulsion, the effect of the emulsion on working performance, mechanical properties and impermeability of UHTCC were studied. The result showed that compared with the control without epoxy emulsion, the type I and type II epoxy emulsion improved the working performance of UHTCC with low dosage. However, the type III epoxy emulsion exhibited an improvement effect on working performance of UHTCC only when the dosage was high. The addition of epoxy emulsion to UHTCC caused a decrease in compressive strength and flexural strength, but epoxy emulsion and hydration products formed an excellent energy absorption mechanism in the specimen and enhanced the elastic modulus of UHTCC. Type I and II epoxy emulsion had little effect on the tensile properties of UHTCC. Type III epoxy emulsion greatly increased the ultimate tensile strength of UHTCC, and the strain hardening phenomenon disappeared at low dosage level, however, the effect of strain hardening had been improved by increasing its dosage.

The mixtures of mesogen-jacketed liquid crystalline polymers (MJLCP) and epoxy resin (E-51) have been prepared in a certain proportion. The category of the MJLCP is poly{2, 5-bis[(4-butoxyphenyl) oxycarbonyl] styrenes} (PBPCS). Methyl tetrahydro phthalic anhydride (MeTHPA) is served as a curing agent, and N, N-dimethylbenzylamine plays the role of catalyst. Then, based on the curing process, the modified materials have been acquired by casting molding. The effect of PBPCS's improvement has been researched through the mechanical properties test, dynamic thermal mechanical test and scanning electron microscope (SEM). The results indicated that PBPCS could apparently improve the mechanical properties of resin E-51. Compared with unmodified materials, the elongation at break and the tensile strength of PBPCS have been improved remarkably through modification. Both mechanical properties of the 4wt% PBPCS/E-51/MeTHPA were enhanced by 48% and 153% separately, and the characteristics of the 3wt% one were raised by 47% and 19% respectively. Also, the ductile fracture morphology of the resins was exhibited in SEM photograph clearly.