M. Mulheron

A broad line NMR and MRI study of water and water transport in portland cement pastes

The results of a magnetic resonance spin-spin relaxation analysis and broad-line magnetic resonance imaging (MRI) (gradient-echo and stray-field imaging) study of water and water transport in Portland cement pastes are presented. The effect of varying the cure conditions and the water to cement (w/c) ratio of the sample of mix are discussed. The water sorptivity and the concentration dependence of the hydraulic diffusion coefficient are calculated for samples prepared with a 0.5 w/c ratio and, therefore, an open pore structure. In the case of 0.3 w/c ratio samples, little water transport is observed, and a closed pore structure is inferred.

Failure of small diameter cast iron pipes

The in-service strength degradation, as a result of corrosion, of cast iron water distribution pipes has been investigated. The strengths of 1 m lengths of pipe extracted from the ground have been measured in either 3- or 4-point bending and the size of the controlling defect has been estimated by visual examination of the fracture surface. The application of Weibull statistics to the bend test data demonstrates that there is bimodal behaviour which suggests that there are two populations of flaws present. It is postulated that the larger flaw size population is associated with corrosion pits that form during the process of graphitisation, while the smaller flaw size population is associated with the inherent flaws within the (brittle) cast iron pipe material. A critical pit depth is identified at the transition between the two competing flaw populations, where there is a change in slope on the Weibull plot. It is shown also that the residual strength/pit depth data are described equally well by either of the two conventional analyses, i.e. loss of section and fracture mechanics.

Generation of thermal strains in GRP

AbstractThe temperature dependence of the linear expansion coefficients in the longitudinal (αl) and transverse directions

Moisture-induced thermal strains in glass fibre reinforced plastic compsites☆

(\alpha _{t_1 } and \alpha _{t_2 } )

The visualization of water transport through hydrophobic polymer coatings applied to building sandstones by broad line magnetic resonance imaging

of unidirectional glass fibre laminates and their matrix resins (αm) has been studied. The results for the dry, fully post-cured polyester, epoxy resins and laminates have been found to be consistent with the predictions of the Schapery equations. An anomalous moisture phenomenon, in the form of a peak in theαm(T)/T andαt(T)/Tcurves for the polyester resin and laminates has been observed. A difference between

Graphitic Corrosion Of A Cast Iron Trunk Main:Implications For Asset Management

\alpha _{t_1 }