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Western Union Telegram from S. Woodward, St. Louis, Missouri, to S. H. Woodward, November 15, 1878
No full textA document from an extensive collection spanning four generations of the Woodward family that operated merchant pig iron companies in West Virginia and Alabama. The collection begins with Stimpson Harvey Woodward (S. H. Woodward), a native of Massachusetts, who moved from Pittsburgh to Wheeling, West Virginia in 1852. He had interests in an iron company as early as 1852 in West Virginia and began Alabama operations in 1869. The family business continued in Alabama until the death of S. H. Woodward's great-grandson in 1965
Study of acidic degradation of alkali-activated materials using synthetic C-(N)-A-S-H and N-A-S-H gels
Get PDFAlkali-activated materials (AAMs) are usually recognized having better acid resistance compared to ordinary Portland cement (OPC), however, the detailed mechanism has not been well studied due to the complexity of raw materials and hardened matrix. In this study, two typical binding gels in AAMs, sodium aluminum silicate hydrate (N-A-S-H) and calcium (sodium) aluminum silicate hydrate (C-(N)-A-S-H), were chemically prepared by laboratory synthesized aluminosilicate powders. The microstructure and composition evolution of the two gels exposed to sulfuric acid were investigated. The results showed that the C-(N)-A-S-H gel had higher degree of structural order than the N-A-S-H gel, while the N-A-S-H gel showed higher polymerization. The AlIV in N-A-S-H gel transferred completely to AlV during sulfuric acid attack, while trace amount of AlIV was still detected in the exposed C-(N)-A-S-H gels. Both gels had increased silica polymerization degree after exposure to sulfuric acid solution. Due to rapider dealumination of N-A-S-H gel than C-(N)-A-S-H gel, the Si/Al ratio increased much higher in the former. The molecular framework changes of N-A-S-H gel caused by dealumination was found to have less effect on the integrity though than that of C-(N)-A-S-H gel, in which coarse gypsum crystalline grains formed and led to destructive stress in hardened matrix. This paper provides an insight at microstructure level of the two typical gels, which is essential for the manufacturing and application of alkali-activated materials
Adsorption and Diffusion of Na+, Cs+ and Ca+2 Ions in C-S-H and C-a-S-H Nanopores
No full textCementitious materials act as a diffusion barrier, immobilizing liquid and solidradioactive waste and preventing their release into the biosphere. The retention capability of hydratedcement paste and its main hydration product, C-S-H gel, has been extensively explored experimentallyfor many alkali and alkaline earth cations. Nevertheless, the retention mechanisms of these cations atthe molecular scale are still unclear. In this paper, we have employed molecular dynamics simulationsto study the capacity of C-S-H to retain Cs, Ca and Na, analyzing the number of high-affinity sites onthe surface, the type of sorption for each cation and the diffusivity of these ions. We have also exploredthe impact of aluminum incorporation in C-S-H at a constant concentration of the ions in the gel pore.We found strong competition for surface sorption sites, with notable differences in the retention of thecations under study and a remarkable enhance of the adsorption in C-A-S-H with respect to C-S-H
Intrinsic sulfuric acid resistance of C-(N)-A-S-H and N-A-S-H gels produced by alkali-activation of synthetic calcium aluminosilicate precursors
No full textThis study investigates the decomposition of alkali-activated materials (AAMs) in sulfuric acid solution. Four sodium-containing calcium aluminium-substituted silicate hydrate (C-(N)-A-S-H) and aluminosilicate hydrate (N-A-S-H) gels with designed Ca/Si and Si/Al ratios are produced with synthetic calcium aluminosilicate powders. The formation of additional calcium products in Ca-rich and Al-sufficient sample is likely helpful to retard the attack of sulfuric acid on the C-(N)-A-S-H/N-A-S-H gels. The Sisingle bondO bond strength of N-A-S-H gel appears weaker than that of C-(N)-A-S-H gel. The calcium in the gels prevents the leaching of silicon from gels. The length of silicon chains in the C-(N)-A-S-H gel increases with increased Si/Al ratio while exposure to acid solution. The chain length of the N-A-S-H gel increases with reduced Si/Al ratio. C-(N)-A-S-H gels show a higher resistance to leaching than N-A-S-H gel, while the latter has a high resistance to depolymerization under acid attack. This study provides a basic route to understand the effect of AAMs composition on acid resistance
09.02.006: Group of soldiers
No full textGroup of soldiers: b&w; 13.8 x 9 cm, St. John’s, Newfoundland: S. H. Parsons and Sons [between 1914 and 1918
Electrostatic properties of C-S-H and C-A-S-H for predicting calcium and chloride adsorption
Get PDFThe adsorption capacity of cement hydrates considerably affects the ionic ingress into cementitious materials. In this study, the surface electrostatic properties of calcium silicate hydrate (C-S-H) and calcium aluminosilicate hydrate (C-A-S-H) were determined to understand the effects of the properties on calcium and chloride adsorption. The density of the surface functional groups was determined by analysing the structure of C-S-H and CASH through Al-27 and Si-29 MAS NMR. The surface sites of SiOH and AlOH are available in CASH whereas C-S-H has SiOH groups for ionic adsorption. We found that the incorporation of aluminium decreases the number of total adsorption sites in C-A-S-H. Furthermore, the site density increased with Ca/(Si + Al). To understand the C-A-S-H/solution interface, a triple-layer surface complexation model was developed and the associated equilibrium constants for depmtonation, calcium, and chloride adsorption were determined by fitting the experimental data of potentiometric titration and zeta potential measurement results. The estimated surface complexation modelling parameters were verified by predicting the experimental data of calcium and chloride adsorption on C-S-H and C-A-S-H
The nanostructure and degradation of C-S-H in Portland and blended cements
Get PDFThe microstructure and composition of water and KOH activated hardened pastes of commercial neat white Portland cement (WPC) and blends with 30% fly ash (PFA) have been characterised using a multi-technique approach, With particular emphasis on the nature of the C-S-H phase. The neat and fly ash blended pastes were activated with water or a 5M KOH solution and cured for one year at 25'C, one month at 55'C and one month at 85'C. The mean length of the aluminosilicate anion structure of C-S-H (29 Si MAS NMR) increased with age and it was higher in the fly ash blended systems. Formulae were presented for the average structural units in the C-S-H present in the systems analysed by TEM-EDX. SEM micrographs showed that as hydration occurred,
the microstructure became denser because outer product C-S-H was formed in the water filled spaces and additional C-S-H resulted from the pozzolanic reaction. The chemical
composition of C-S-H could not be determined by SEM-EDX because of intermixing with other phases; TEM-EDX was necessary. Inner product C-S-H morphology was fine and homogeneous and that of outer product C-S-H was fibrillar in the water activated systems and foil-like with alkali activation. Fly ash replacement did not change the morphology of lp and Op C-S-H. Small fully hydrated cement and PFA particles were filled with a less dense lp C-S-H with morphology very similar to the foil-like one. TEM-EDX showed that, in general, the mean Ca/(AI+Si) atomic ratio was lower in the water activated blends than that in the neat cement pastes due to the fly ash reaction. The composition- structure data were discussed in terms of models for the nanostructure of C-S-H.
Higher curing temperature accelerated the rate of the cement hydration. The mean length of the aluminosilicate of the C-S-H anions was much higher than that of C-S-H formed at lower temperatures, and it was also higher in the blended pastes than with neat cement. Backscattered electron images showed that the grey level of C-S-H in the
systems cured at 55T and 85T was in places quite similar to that of the calcium hydroxide: that is, it was brighter than in pastes cured at lower temperature. SEM also showed that the microstructure of the systems cured at higher temperature exhibited non uniform porosity. Inner product C-S-H with a fine scale, homogeneous morphology,
was abundant in all systems cured at 55'C and 85'C. Op C-S-H was generally fibrillar with Nvater, and foil-like with alkali. However, the higher temperature curing did result
in coarser fibrillar morphology (water activated systems) than that formed at lower temperatures.
The C-S-H gel formed in the commercial WPC-30% PFA blended paste hydrated for one year at 25'C and water leached for twelve weeks was also characterised in this work. A matrix effect was clearly observed by 29 Si MAS NMR. Cross-linking of the aluminosilicate anion structure of C-S-H occurred after leaching the sample for four weeks. Formulae were also presented for the average structural units in the C-S-H
present in the unleached and four weeks water leached systems analysed by TEM-EDX. lp C-S-H morphology was fine and homogeneous and Op C-S-H had fibrillar morphology. There were many areas in the microstructure of the leached sample where Op C-S-H with foil-like morphology coexisted with fibrillar Op C-S-H
Letter from James Fitton, Bellaire, Ohio, to S. H. Woodward, Wheeling, West Virginia, December 26, 1883
No full textA document from an extensive collection spanning four generations of the Woodward family that operated merchant pig iron companies in West Virginia and Alabama. The collection begins with Stimpson Harvey Woodward (S. H. Woodward), a native of Massachusetts, who moved from Pittsburgh to Wheeling, West Virginia in 1852. He had interests in an iron company as early as 1852 in West Virginia and began Alabama operations in 1869. The family business continued in Alabama until the death of S. H. Woodward's great-grandson in 1965
Promissory note from J. L. Woodward to S. H. Woodward, January 16, 1879
No full textA document from an extensive collection spanning four generations of the Woodward family that operated merchant pig iron companies in West Virginia and Alabama. The collection begins with Stimpson Harvey Woodward (S. H. Woodward), a native of Massachusetts, who moved from Pittsburgh to Wheeling, West Virginia in 1852. He had interests in an iron company as early as 1852 in West Virginia and began Alabama operations in 1869. The family business continued in Alabama until the death of S. H. Woodward's great-grandson in 1965
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