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The purpose of this study is to use thermodynamic data to estimate the pressure exerted by the crystallization of iron oxyhydroxides following the equation proposed by Correns and Steinborn.

Standard free energy and molar volume data have been considered for goethite, lepidocrocite, magnetite and hematite, which are described in the literature as the most commonly found mineral phase rust constituents.

The studied mineral phases generate higher to lower crystallization pressure values in the following order: goethite > lepidocrocite > hematite > magnetite. The crystallization pressures calculated for these phases are in the 32-350 MPa range, which is higher than the tensile strength of concrete (of the order of 0.2-10 MPa) and thus leads to failure of the cover concrete.

The aim of this paper is to shed light on this issue by calculating the stresses generated by the crystallization of iron oxide from a supersaturated solution using thermodynamic data. A deliberately simplistic method was proposed, taking as reference the Correns–Steinborn model (Correns and Steinborn, 1939; Correns, 1949). The crystalline phases considered in this paper are those most commonly found in the literature as rust constituents, that is, goethite (α-FeOOH), lepidocrocite (γ-FeOOH), magnetite (Fe₃O₄) and hematite (α-Fe₂O₃). The FeO synthetic phase was also included as a reference.

The purpose of this paper is to determine if a type of cactus mucilage, Opuntia ficus-indica (OFI), may act as a corrosion inhibitor for carbon steel in cement-based materials (mortar) exposed to chloride-laden environment.

Mortar prisms, reinforced with carbon steel rods, were immersed in sodium chloride (NaCl) solution for five wet – dry cycles. The experimentation included electrochemical monitoring (corrosion potential, Ecorr, and polarization resistance, Rp) of carbon steel during the time of exposure until corrosion-induced cracking appeared at the mortar surface. Crack survey on the mortar prisms was performed. Carbon steel rods were retrieved from the mortar after crack survey and steel mass loss at the end of the experimental period was estimated. A comparison between the different mixtures was also performed.

OFI mucilage did perform as a corrosion inhibitor of steel in chloride contaminated mortar.

The experimental program needs to be corroborated in concrete specimens with typical dimensions. The surface oxide/hydroxide formation of the carbon steel in contact with the OFI mucilage is still unknown; thus, electrochemical impedance spectroscopy (EIS) and X-ray diffraction (XRD) analyses are needed.

OFI mucilage is a suitable natural product that can be used to increase durability of concrete structures not only in countries where OFI cactus is produced, but also in many other countries where this plant is considered a plague.

The new information obtained from this paper is the innovative use of a by-product of this cactus plant for construction industry applications.

This paper aims to study the value of informal care (IC) time from the perspective of caregivers using two alternative contingent valuation tools – willingness to pay (WTP) and willingness to accept (WTA) – and to identify the variables that affect the stated values.

The authors used data from a multi-centre study of 610 adult caregivers conducted in two Spanish regions in 2013. The existence of “protest zeros” and “economic zeros” because of the severe budgetary constraints of the households was also considered. Two-part multivariate models were used to analyse the main factors that explained the declared values of WTA and WTP.

The average WTP and WTA were €3.12 and €5.98 per hour of care, respectively (€3.2 and €6.3 when estimated values for “protest zeros” and “economic zeros” were considered). Some explanatory variables of WTA and WTP are coincident (place of residence and intensity of care time), whereas other variables only help to explain WTP values (household and negative coping with caregiving) or WTA values (age and burden of care). Some nuances are also identified when comparing the results obtained without protest and economic zeros with the estimated values of these special zeros.

Studies analysing the determinants of WTP and WTA in IC settings are very scarce. This paper seeks to provide information to fill this gap. The results indicate that the variables that explain the value of IC from one perspective may differ from the variables that explain it from an alternative perspective. Given the relevance of contextual factors, studies on the topic should be expanded, and care should be taken with the extrapolation of results across countries and settings.

The purpose of this paper was to develop a loaf bread enriched with naranjilla (lulo) fruit (shells, seeds and pulp) and determine the technical quality, sensory acceptability and bioavailability (by in vitro digestion) of antioxidant components.

Loaf bread was prepared by using a no-time bread-making process. The crumb moisture, specific volume, crust and crumb color, texture profile analysis, analysis of the crumbs' alveoli, sensory evaluation, in vitro simulation of gastrointestinal digestion and antioxidant capacity were determined. Data were analyzed with one-way ANOVA (α = 0.05).

The specific volume was reduced by 21% (4.62 cm3/g, p < 0.0001), and the hardness was increased by 70% (2.9 N, p < 0.0001). Enrichment of the bread with naranjilla fruit (NF) contributes a yellowish coloration to the bread, which was very well accepted by the consumers and could be considered a natural colorant alternative. Moreover, the sensory evaluation indicated that the analyzed attributes (appearance, color, odor, taste, firmness and overall quality) of the naranjilla bread presented scores higher than 6.5 of 9 points hedonic scale. Naranjilla in the bread formulation had good acceptability by consumers. Naranjilla-enriched bread had an increase in total phenolic (TP)compounds and total carotenoids. In the product without digestion, naranjilla bread increased 1.7 times for TP, 50 times for CT and 1.3 times for TEAC, compared to the control bread (p < 0.0001). The percentage of bioaccessibility for fresh bread without digestion was 39.2 and 53.9% for the control and naranjilla bread, respectively. The addition of NF contributes to a higher TP compounds content and favors its bioavailability.

For bread production, fruits that do not meet the quality standards to be consumed as a natural fruit can be used. In this way, these fruits can contribute as a potential use to reduce agro-industrial waste and as a natural colorant.

Naranjilla is a native fruit from the subtropical Andean regions, which has high ascorbic acid concentrations, making it a fruit rich in antioxidants. Naranjilla-enriched bread contributes with beneficial compounds for the consumer.