Experimental investigation of effect of admmixture on concrete strength and frost-resistance
The influence of admixture on concrete strength and frost-resistance was analyzed by using the mercury intrusion method and the rapid frozen-thaw method under the condition of the same water/binder ratio in this paper. The results showed that the intensity of the concrete with single doped compound mineral admixture is slightly lower than the normal concrete's in concrete 28-days strength experiment when the fixed water/binder ratio is 0.38, but the extent of the concrete strength growth is bigger, and maybe exceed the normal concrete's at the late period of the whole session. It also could be found that the concrete strength added single air entraining agent is lower, particularly the strength of the concrete double mixed with compound mineral admixture and air-entraining agent is lowest. In term of the pore structure, the porosity rate of concrete can be lower and the harmful hole is decreased as well as the less-harmful hole and no-harmful hole are increased when the compound mineral admixture is mixed. The porosity rate will increase, closed pore and less-harmful hole will enhance by a wide margin if the admixture of air entraining agent is added. Moreover, the pore size distribution of concrete becomes reasonable if these two substances are admixed at the same time. From the aspect of frost-resistance, the concrete with co-doped compound mineral admixture and air-entraining agent is best, the concrete with uni-doped air-entraining agent is better secondarily and the concrete with compound mineral admixture alone is just slightly better.
The Science and Technology of Civil Engineering Materials
I. THE FUNDAMENTALS OF MATERIALS. 1. Atomic Bonding. 2. The Architecture of Solids. 3. Development of Microstructure. 4. Surface Properties. II. BEHAVIOR OF MATERIALS UNDER STRESS. 5. Response of Materials to Stress. 6. Failure and Fracture. 7. Rheology of Fluids and Solids. 8. Fatigue. III. PARTICULATE COMPOSITES: PORTLAND CEMENT AND ASPHALT CONCRETES. 9. Particulate Composites. 10. Aggregates. 11. Portland Cement Concrete. 12. Asphalt Cements and Asphalt Concrete. IV. STEEL, WOOD, POLYMERS, AND COMPOSITES. 13. Steel. 14. Wood and Timber. 15. Polymers and Plastics. 16. Fiber Reinforced Composites. Solutions to Numerical Problems. Index.
Mercury porosimetry and effective networks for permeability calculations in porous materials
Abstract It is shown that a mercury porosimetry measurement can be considered as generating a mapping between a real pore structure and a random network of cyclindrical tubes. The mapping is shown to preserve the hydraulic conductivity of individual pores having elliptical cross-sections. Thus, the assumption of circular cylindrical pores, commonly used to interpret mercury porosimetry results, does not necessarily invalidate the use of these measurements to predict the permeability of porous media with the Katz—Thompson equation. A regular lattice of randomly sized tubes with elliptical cross-sections is considered as a specific test of these ideas.