Engineering Commons^™

Alkali-Activated Natural Pozzolan/Slag Binder For Sustainable Concrete, Meysam Najimi

UNLV Theses, Dissertations, Professional Papers, and Capstones

This study aimed to fully replace Portland cement (PC) with environmentally friendly binders capable of improving longevity of concrete. The new binders consisted of different proportions of natural Pozzolan and slag which were alkaline-activated with various combinations of sodium hydroxide and sodium silicate. A step-by-step research program was designed to (1) develop alkali-activated natural Pozzolan/slag pastes with adequate fresh and strength properties, (2) produce alkali-activated natural Pozzolan/slag mortars to assess the effects of dominant variables on their plastic and hardened properties, and (3) finally produce and assess fresh, mechanical, dimensional, transport and durability properties of alkali-activated natural Pozzolan/slag concretes. The …

Innovating Two-Stage Concrete With Improved Rheological, Mechanical And Durability Properties, Manal F. Najjar

Electronic Thesis and Dissertation Repository

Two-stage concrete (TSC), also known as preplaced aggregate concrete, is a special type of concrete that is produced using a unique procedure which differs from that of conventional concrete. TSC is distinguished by its high coarse aggregate content and exceptional placement technique, whereby aggregates are first pre-placed in the mold then injected with a special grout. The preplacement of aggregates saves substantial energy since only the grout needs mechanical mixing; the grout is self-leveling and needs no vibration and no mechanical compaction. However, TSC applications are still limited despite substantial advancement of modern concrete technology. Therefore, there is a need …

Pyrolysis Of Dried Wastewater Biosolids Can Be Energy Positive, Patrick J. Mcnamara, Jon Koch, Zhongzhe Liu, Daniel Zitomer

Civil and Environmental Engineering Faculty Research and Publications

Pyrolysis is a thermal process that converts biosolids into biochar (a soil amendment), py-oil and py-gas, which can be energy sources. The objectives of this research were to determine the product yield of dried biosolids during pyrolysis and the energy requirements of pyrolysis. Bench-scale experiments revealed that temperature increases up to 500 °C substantially decreased the fraction of biochar and increased the fraction of py-oil. Py-gas yield increased above 500 °C. The energy required for pyrolysis was approximately 5-fold less than the energy required to dry biosolids (depending on biosolids moisture content), indicating that, if a utility already uses energy …

Systems Approach To Link Big Socio-Ecological Geo-Data To Food Systems Sustainability, Quang Bao Le, Chandrashekhar Biradar, Enrico Bonaiuti, Richard Thomas

International Congress on Environmental Modelling and Software

Rapid development of multi-dimensionally, multi-scale, timely updated socio-ecological geo-data presents an opportunity as potential information resource for supporting effective decision- making of stakeholders involved with food systems, from daily routines of individuals to strategic decisions of manager and policy-makers. However, the use of this type of big data toward supporting the sustainability of food systems at different scales still fall short of (i) what information commonly needed by food system actors to response and adapt to socio-ecological change and enhance the system performance, (ii) interoperability between different types of data across scales, and (iii) sufficient guidance to utilize big data …

Methodological Abilities Of Integrated Models To Support Agricultural Landscape Resilience: Current Status And Research Perspectives, Quang Bao Le

International Congress on Environmental Modelling and Software

It is important to increase the resilience of rural landscapes in the face of global changes. It is widely recognized that integrated modeling is often a methodological choice to study landscape resilience because the task is often beyond the ability of direct, empirical studies. However, so far there has not yet been a systemized, critical review on methodological abilities current modeling approaches can have for supporting management for agricultural landscape resilience. This review study (i) highlighted the methodological abilities of integrated system modeling ideally needed for agricultural landscape management for resilience, (ii) reviewed strengths and weakness of common integrated modeling …

The Role Of Social Institutions In The Resolution Of International Conflicts Over Shared Fishing Resources, Cezara Păstrăv, Frank Dignum

International Congress on Environmental Modelling and Software

International conflicts over shared fishing resources may rise in numbers in the context of climate change, which has lead, and will continue to lead, to changes in behavior patterns and geographic distribution of fish and other marine resources of interest to the fishing industry. Under these circumstances, being able to quickly adapt to unexpected changes becomes a very desirable trait for the fishing industry. Unfortunately, the current conflict resolution processes are often difficult, time consuming and sometimes not maintained.

We are interested in whether more sustainable mechanisms, that act from the bottom up and are easier to enforce by the …

Exploration Of The Long Term Sustainability Of The French Risk Management, Frédéric Grelot, Bruno Bonté, Zhongyang Fang

International Congress on Environmental Modelling and Software

Public flood risk management (FRM) in France, as in other countries like USA, Great Britain, relies on a combination of tools dealing with the negative consequences of flood. Spatial scale of those tools differs: insurance is defined and managed at national scale, land use regulation is defined at national scale but implemented at local scale, protection against flood may be implemented at local or even individual scales. The objective of this communication is to build a model for the analysis of the sustainability of the French FRM. For this, we used a simple but contextualized agent-based model (Cat-Nat ABM).

In …

A Multi-Objective Sustainable Model For Transportation Asset Management Practices, Marketa Vavrova

Open Access Theses & Dissertations

Transportation Asset Management (TAM) practices have gained popularity in the United States and worldwide with the aim to provide the required level of service for the transportation infrastructure network in the most cost-effective manner. However, TAM is a complex decision-making process because many objectives and different perspectives, often producing conflicting goals, must be considered.

This Dissertation presents a Multi-Objective Sustainable (MOS) model to integrate economic, social, and environmental sustainable objectives into TAM decision-making. The objective is to develop a holistic multi-objective asset management approach integrating environmental and social sustainability related performance measures with traditional indicators, such as asset condition and …