Porous melt-derived bioactive glass scaffolds with interconnected pore networks suitable for bone regeneration were produced without the glass crystallising. ICIE 16 (49.46% SiO 2 , 36.27% CaO, 6.6% Na 2 O, 1.07% P 2 O 5 and 6.6% K 2 O, in mol%) was used as it is a composition designed not to crystallise during sintering. Glass powder was made into porous scaffolds by using the gel-cast foaming technique. All variables in the process were investigated systematically to devise an optimal process. Interconnect size was quantified using mercury porosimetry and X-ray microtomography (CT). The reagents, their relative quantities and thermal processing protocols were all critical to obtain a successful scaffold.Particularly important were particle size (a modal size of 8 m was optimal); water and catalyst content; initiator vitality and content; as well as the thermal processing protocol.Once an optimal process was chosen, the scaffolds were tested in simulated body fluid (SBF) solution. Amorphous calcium phosphate formed in 8 h and crystallised hydroxycarbonate apatite (HCA) formed in 3 days. The compressive strength was measured to be approximately 2 MPa for a mean interconnect size of 140 m between the pores with a mean diameter of 379 m, which is thought to be suitable porous network for vascularised bone regeneration.This material has the potential to bond to bone more rapidly and stimulate more bone growth than current porous artificial bone grafts.

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Drying and wetting induce a number of microstructural changes that could impact transport properties and durability of concrete structures, but their significance is not well-established. This research examines pastes, mortars and concretes with different w/b ratios, binders, aggregate sizes, curing and conditioning regimes. 50 mm thick samples were dried to equilibrium at either 105C, 50C / 7% RH, 21C / 33% RH or gentle stepwise at 21C / 93% RH  3% RH, and then rewetted stepwise by humidification at 21°C / 33% RH  86% RH and full saturation to produce varying degrees of damage and moisture content. Oxygen diffusivity and permeability, electrical conductivity, microcracking, accessible and total porosity were measured at different conditioning stages over 3-year period to better understand the effects of shrinkage, hysteresis and drying-induced damage on transport properties. The effect of supplementary cementitious materials (GGBS, SF) and implications of dryingwetting on concrete durability are discussed.

The production of nanofibers of bioactive glass by laser spinning is reported. The technique yields a great quantity of free-standing fibers in the form of a mesh of disordered intertwined fibers. The method does not rely on chemical processing and does not need any chemical additive. It involves melting of a precursor material with tailored composition, which makes it possible to produce nanofibers from materials with which conventional melt drawing techniques cannot be used. Herein, the production of 45S5 Bioglass® nanofibers is reported for the first time. The process is very fast (nanofibers of several centimeters are grown in a fraction of a second), without the necessity of post heat treatments, and no devitrification was observed as a result of 2 the laser spinning process. The morphology, composition and structure of the nanofibers were characterized and their bioactivity assessment was carried out by immersion in SBF. This technique provides a method for the rapid production of dense glass nanofibers which can be employed as bioactive nanocomposite reinforcement, as a synthetic bone graft to replace missing bone, or to produce 3D structures for use as scaffolds for bone tissue engineering.

This paper concerns understanding the influence of drying induced microcracking on water absorption by capillary suction. Paste, mortar and concrete samples with different binder type, w/b ratio, thickness, aggregate size, and curing age were tested. Samples were subjected to gentle stepwise drying at 21°C / 93% → 55% RH, or drying at 21°C / 55% RH, 21°C / 0% RH, 50°C or 105°C to induce microcracks less than 100 m wide. Results show that the presence of microcracks causes cumulative water absorption to scale non-linearly with √ . The observed relationship is approximately sigmoidal / S-shaped, with the position of inflection point related to microcracking and the degree of non-linearity increasing with drying severity. A simple fluorescence imaging method was developed to enable continuous monitoring of the advancing wetting front and to study the effect of microcracks. Quantitative image analysis of water penetration produced results consistent with gravimetric measurements.