Physicochemical studies of the destructive alkali-aggregate reaction in concrete

Abstract

In a further stud.I' of t he a lka li-aggregate reaction in high-alkali cements, 11 reactiv e a nd nonreactive experimental aggregates were examined by several procedures. On comparing t he results of each m ethod with th e standard expansion-bar test, it appears that eac h property studied has some bearing on the expansion characteristics of each aggregate. For exa,mple: (1) The chemical durabili ty as determined by the interferometer procedure was poor for t he aggregates t hat showed excessive expansion, but not a ll aggregates that are shown to be chemically reactive by this procedure will cause expansion, (2) all aggregates are suffi cie ntly hygroscopic to attract the water necessary for t he reaction if other properties arc also favorable, (3) s urface electrical-resistance measurements confirm the hygrosco picity determinations; however, fr ee ions in glasses may have considerably more effect on the surface resistance of certain glasses than do thei r hygroscopic properties, and (4) the uneve n di stribution of migratable ions bet\\'een the aggregate surface and the outer phase offers a mechan ism for the' osmotic swellin g of individual aggregate grains, with accompany ing cxp,wsioll in CO Il CI' l'{l' members.

Efficient One-Step PEG-Silane Passivation of Glass Surfaces for Single-Molecule Fluorescence Studies

“…Soaking the slides in dry acetone prior to attaching PEG-silane was crucial to remove any water molecules adsorbed at the glass/air interface due to the hygroscopic nature of glass surfaces. 33 Given our extremely dry winter conditions, we had observed better surfaces in the winter season, which made us realize how critical this step is. Any residual water would elicit the premature hydrolysis of the PEG-Si(OEt) 3 (eq 2).…”

“…To clean the coverslip and also maximize the number of silanol groups exposed, we performed a piranha solution cleaning (90 min) followed by a mild etching using NaOH (0.5 M for 30 min). Soaking the slides in dry acetone prior to attaching PEG-silane was crucial to remove any water molecules adsorbed at the glass/air interface due to the hygroscopic nature of glass surfaces . Given our extremely dry winter conditions, we had observed better surfaces in the winter season, which made us realize how critical this step is.…”

From Waste to Renewables: Challenges and Opportunities in Recycling Glass Fibre Composite Products from Wind Turbine Blades for Sustainable Cement Production

“…There is no doubt that the higher the specific surface area of the glass powder, the greater its pozzolanic activity. An analysis of scientific studies has also shown that the addition of finely ground glass powder with a specific surface area of 0-0.079 mm causes, similar to the addition of slag, fly ash, or silica fume [71], a reduction in the shrinkage of mortars and concretes compared to reference samples without additives. The indicated specific surface area of the powder also limits material destruction in cases where the sample contains reactive aggregates.…”

The usage of fluorescent waste glass powder in concrete

“…In the sixties, many studies were devoted to the use of crushed glass waste as an aggregate for concrete production [4][5][6]. This aggregate was also applied in road construction.…”