Partially Replacing Fly Ash with Limestone Powder in the Paste - Influence and Characterization
Paste filling is an important research direction of coalmine "green mining" which can dispose coalmines solid waste and achieve environmental protection. The mechanical properties such as compressive strength, workability, ulti- mate tension value, shear strength and splitting strength of paste, in which the fly ash was partially replaced by limestone powder, was studied. Adiabatic temperature rise, setting time, shear strength, permeability, frost resistance and dry shrinkage of different substitution rate were investigated and the results were compared with traditional paste. The test re- sults showed that the influence of limestone powder on workability, permeability and frost resistance performance of paste was slight, the setting time of paste were shortened, adiabatic temperature rise and mechanics performance of paste were decreased, dry shrinkage value was increased with limestone powder content increasing.
Influence of Mass Fractions of Limestone Powder on Mechanical Property and Durability of Concrete
A series of experiments were carried out to investigate the effect of stone powder content and different way of mixture on the workability,different age of compressive strength,modulus of elasticity,drying shrinkage,coefficient of permeability as well as freezingthawing resistance of concrete.The mechanisms of action,the best mass fractions and optimal way of stone powder were analyzed.The studies show that the performance of concrete is the best when the stone power content is between 15% and 20%.
Nuclear spin-lattice relaxation in transition metal compounds with local tetragonal symmetry.
We report on the various contributions to the total spin-lattice relaxation rate in metallic materials with local tetragonal symmetry. The analytical formulae are given in the tight-binding approximation. The calculations show the relation between various partial electron densities of states and corresponding contributions to the relaxation rates. The presented formulae can be used to compare theoretically calculated electron band structure parameters with those obtained from NMR spin-lattice relaxation time measurements.