Investigation of relations between porosity, pore structure, and C1− diffusion of fly ash and blended cement pastes

Immobilization of Technetium and Nitrate in Cement-Based Materials

“…Both 00 Tc and nitrate index values for most grouts tested in this work exceeded the 7.0 requirement. There are a number of literature references [8][9][10] showing that blended cements containing ground blast furnace slag and/or fly ash, form products with finer pore structures than are formed with ordinary cements, and that diffusion through these products is at a slower rate. Our results, showing greater leachability index values with increase in grout ground blast furnace slag content, increase in grout mix ratio, and increase in grout density are consistent with the literature information, to the extent that such blend modifications decrease pore size or otherwise favorably affect grout pore properties.…”

Kinetics of Fly Ash Beneficiation by Carbon Burnout

“…Typical specifications state that fly ash may be used to replace up to 15% of Portland cement (7)(8)(9)(10)(11)(12)(13)(14) …”

“…These levels are usually designated as Loss on Ignition, which provides a rough estimate of the true value, as the test procedure is designed to oxidize any combustibles by using high temperatures and long residence times. The American Society for Testing and Materials has established a maximum value of 6% residual carbon in fly ash used in concrete, but levels no higher than 3% are generally demanded by the industry when the ash is sold to replace cement in concrete (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19).…”

Fly Ash Concrete for Highway Use

“…Clogging of pores by gel produced from pozzolanic reaction has been indicated as one of the possible Umiting mechanisms [219]. The effect of fly ash on the composition of the concrete pore solution has also been considered to be important [219,220], especially the concept that decreased concentrations of Na"^, Tables 10.3 The results are given in Table 10.4-1.…”

“…The effect of fly ash on the composition of the concrete pore solution has also been considered to be important [219,220], especially the concept that decreased concentrations of Na"^, Tables 10.3 The results are given in Table 10.4-1. This is brought out more clearly in Figure 10.…”