Composition, silicate anion structure and morphology of calcium silicate hydrates (C-S-H) synthesized by silica-lime reaction and by the controlled hydration of tricalcium silicate (C3S)

The main product of Portland cement hydration is C-S-H. Despite constituting more than half of the volume of hydrated pastes and having an important role in strength development, very little is known about the factors that determine its morphology. To investigate the relationship between the chemical composition, silicate anion structure and morphology of C-S-H, samples were synthesized via silica-lime reactions and by the hydration of C3S under controlled lime concentrations and with/ without accelerators. The silicate anion structure of the samples was studied by 29Si MAS NMR and the morphology and chemical composition by TEM and SEM. All samples prepared via silica-lime reactions with bulk Ca/Si up to 1.5 were foil-like. The hydration of C3S at fixed lime concentration yielded foil-like C-S-H for [CaO]22mmol/L. A relationship between the silicate anion structure and the morphology of C-S-H was found for the samples fabricated with accelerators

Thermal stability of C-S-H phases and applicability of Richardson and Groves’ and Richardson C-(A)-S-H(I) models to synthetic C-S-H

Synthetic C-S-H samples prepared with bulk C/S ratios from 0.75 to 1.5 were analyzed by coupled TG/DSC/FTIR and in-situ XRD while heating, in order to correlate observed weight loss curves with the kinetics of evolved gases, and to investigate the transformations C-S-H→β-wollastonite→α-wollastonite. The temperature of the transformation to β-wollastonite increased with increasing C/S. The temperature for the transformation from β- to α-wollastonite meanwhile decreased with increasing C/S; indicating that excess CaO stabilized the α-polymorph. The transformation C-S-H→β-wollastonite was accompanied by the formation of α`LC2S for C/S > 1. In the case of C-S-H with C/S = 1.5, both β-C2S and rankinite were formed and then decomposed before the transformation to β-wollastonite and α`LC2S. C-S-H with low C/S was found to be more stable upon heating. The chemical structural models of Richardson and Groves’ and Richardson C-A-S-H(I) were used to obtain the structural-chemical formulae

Inventering av ängar och hagar i Strömstads kommun

De senaste årtiondenas förändringar av jordbruket, som lett till stordrift och en omfattande kemikalieanvändning har fört med sig att arealen naturliga fodermarker starkt har minskat. Dessa marker är mycket viktiga för många växt- och djurarter och utvecklingen har medfört att många av dessa arter har blivit utrotningshotade. Denna inventering ingår i en landsomfattande inventering som startades av Statens naturvårdsverk 1985 och syftar till att få kännedom om vilka skyddsvärda fodermarker som finns i Strömstads kommun. Dessa uppgifter kan sedan bland annat användas som underlag vid statlig och kommunal planering och för styrning av ekonomiskt stöd till de mest värdefulla områdena. Nuvarande stöd är främst det så kallade NOLA bidraget, som utgår för "Naturvårdsåtgärder i odlingslandskapet" De marker som främst finns medtagna i inventeringen är välhävdade naturliga fodermarker med floristiska kvaliteter. Medtagna är också marker som tills nyligen har varit hävdade och som uppvisar kvarstående floristiska värden.Regionala inventeringsrapporter import från MDP 2015-05</p