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Shotcrete is widely used in underground and tunneling applications due to their superior flexural properties and impact resistance. There is a higher need in improving these properties by adding various admixtures and fiber reinforcements to achieve superior performance to accomplish faster turnout in tunneling constructions. In this study, the effect of three accelerators on the long-term flexural performance of steel-fiber reinforced shotcrete were investigated. The types of accelerators used were aluminate, cement mineral, and alkali-free accelerators, whose effects on the flextural properties were investigated over the periods of 1, 3, 6, 12, and 24 months. The flexural toughness was first estimated in accordance with JSCE SF-04, where up to span/150 deflection area under the load-deflection curve was used for calculating the flexural toughness. Whereas ASTM C1018–97 was used to evaluate the first-crack and post-peak load toughness behavior with three specified points for better understanding the flexural behavior of all mixtures. Moreover, it is important to use alkali-free accelerators in terms of both the long-term performance of the tunnels and the safety of the workers. The long-term performances of the specimens showed by the compressive strength and flexural strength were comparable. Finally, according to the long-term effectiveness and performance, the best mix design for the tunnel construction sites is also proposed.

Many studies have examined the effects of climate change on farmland value in developed countries, but our understanding of the impact of climate change on farmland value is still very limited, especially in developing countries. In this study, we aimed to assess the effects of climate change on farmland value in Bangladesh using the Ricardian model. Household-level data collected from seven selected agroecological zones in Bangladesh were used to estimate the relationships among farmland value and long-term climate, farm household, and policy variables. The results showed that the current land values of farmers are sensitive to climate. A new variable called “flooding” was added to the Ricardian model, and the results indicated that floods are responsible for reductions in farmland value, especially in lowland areas. Among the socio-economic variables, the availability of extension services and access to irrigation facilities were positively correlated with farmland value. The estimated marginal impact results suggested that increases in temperature were associated with losses in small farmland value, whereas the precipitation levels in both seasons positively influenced farmland value. Selected global climate models predicted that climate change would have a negative impact on land value depending on the climate model and source of farm income. The empirical findings obtained from this study are expected to contribute to the formulation of sustainable adaptation strategies to maintain farm productivity and farmland value in Bangladesh in the context of climate change.

Climate change may influence crop income negatively or positively. To address this, present study is an attempt to quantify the impacts of climate change on net income from crop farming in Bangladesh using Ricardian method. For estimating the relationship between net crop income and climatic parameters, farm household and climate data were collected from the selected agro-ecological zones (AEZs) in Bangladesh. The results revealed that net crop income is sensitive to climate, particularly to seasonal temperature. Temperature rise was found to be positively influencing net crop income in AEZs having adequate irrigation facilities. Marginal impact estimates suggest that increase in temperature and rainfall will lead to increase in net income from crop farming in Bangladesh. However, the impacts will vary significantly across cropping seasons and space (studied AEZs). Using selected AOGCM scenarios, the study predicts that net crop incomes are expected to increase in the future. The empirical findings underscore the need for policy makers to take agro-ecological zones specific effects of climate change into consideration when formulating and implementing the adaptation strategies in Bangladesh.