Introduction Doa
The stability of fresh concrete is characterized by its resistance to washout loss, segregation, and bleeding and is affected by the mix proportioning, aggregate shape and gradation, the extent of vibration compaction and placement conditions.1'2 Whenever concrete is cast through water, the differential velocity at the interface between the fresh concrete and surrounding water can erode cementitious materials CM and other fines from the concrete. Such erosion can dramatically impair the...
Extended Abstract Ufh
The interaction of pore fluid with silicate and alum nate cement and cement hydration products plays a central role in controlling most of the important chemical reactions and mechanical properties of concrete, including strength development, rheology, durability, creep and cracking. Many of these interactions occur at the fluid-solid interface or in confined volumes with characteristic dimensions from 1 to 100 nm. Investigation of these nano-scale interactions on a molecular scale is difficult...
Xrd
Figure 4 presents XRD traces of the samples prepared with sodium silicate and sodium hydroxide solutions. It was found that the main phases formed in the samples are amorphous, and only in case of materials prepared with sodium hydroxide solution semi-crystalline zeolitic phases were present after 1 month of storage. The zeolitic products formed depended on the curing regime. In materials with 2 hours precuring at room temperature and exposed to elevated temperature curing at 75 C as in Case I...
Info Lyn
Figure 8 Correlation between compressive strength and coarse capillary porosity a Non linear regression for all data b Linear regression for various water cement ratios Figure 8 Correlation between compressive strength and coarse capillary porosity a Non linear regression for all data b Linear regression for various water cement ratios Figure 9 Compressive strength vs. gel space ratio for mortars without admixtures The gel space ratio in the Powers-Brownyard expression15 for estimating...