01594638

Component

High volume fly ash (HVFA) mortars and concretes have been widely investigated as sustainable materials with acceptable mechanical properties and good durability performance. Following a statistical design of experiments, this work prepared a total of 21 HVFA mortar mixtures and tested and modeled their compressive strength and splitting tensile strength at various ages. Both the strength properties of HVFA mortars decrease with the increase in fly ash replacement and water-to-cementitious-materials ratio (W/CM). For the three selected HVFA mortars, those with higher fly ash replacement and higher W/CM showed higher water absorptivity and lower surface resistivity. Microscopic examination by different modes of an electron probe micro-analyzer was conducted to shed light on t he hydration behavior of these three representative mortars. It seems that the mortar with lower fly ash replacement corresponds to more significant Ca depletion from fly ash spheres, implying the beneficial role of Portland cement in activating the fly ash. In all three HVFA mortars, there were various levels of Si and Al depletion around the surface of fly ash spheres and complete S depletion from fly ash spheres. The hydration products of these fly ash particles are Ca-rich and S-rich. .

This paper was sponsored by TRB committee AFN10 Standing Committee on Basic Research and Emerging Technologies Related to Concrete. Alternate title: Electron Pprobe Microanalyzer Investigation into High-Volume Fly Ash Mortars.

01584066

16-6139

English

23p

2016

Transportation Research Board 95th Annual Meeting

Digital/other

Figures; References; Tables

Cement mortars; Compressive strength; Fly ash; Laboratory tests; Mix design; Portland cement

Highways; Materials

Transportation Research Board Annual Meeting 2016 Paper #16-6139

TRIS, TRB, ATRI

Jan 12 2016 6:42PM