PHREEQC version 3 is a computer program written in the C and C++ programming languages that is designed to perform a wide variety of aqueous geochemical calculations. PHREEQC implements several types of aqueous models: two ion-association aqueous models (the Lawrence Livermore National Laboratory model and WATEQ4F), a Pitzer specific-ion-interaction aqueous model, and the SIT (Specific ion Interaction Theory) aqueous model. Using any of these aqueous models, PHREEQC has capabilities for (1) speciation and saturation-index calculations; (2) batch-reaction and one-dimensional (1D) transport calculations with reversible and irreversible reactions, which include aqueous, mineral, gas, solid-solution, surface-complexation, and ion-exchange equilibria, and specified mole transfers of reactants, kinetically controlled reactions, mixing of solutions, and pressure and temperature changes; and (3) inverse modeling, which finds sets of mineral and gas mole transfers that account for differences in composition between waters within specified compositional uncertainty limits.

To understand hydrochemistry and to analyze natural as well as man-made impacts on aquatic systems, hydrogeochemical models have been used since the 1960’s and more frequently in recent times. Numerical groundwater flow, transport, and geochemical models are important tools besides classical deterministic and analytical approaches. Solving complex linear or non-linear systems of equations, commonly with hundreds of unknown parameters, is a routine task for a PC. Modeling hydrogeochemical processes requires a detailed and accurate water analysis, as well as thermodynamic and kinetic data as input. Thermodynamic data, such as complex formation constants and solubility-products, are often provided as databases within the respective programs. However, the description of surface-controlled reactions (sorption, cation exchange, surface complexation) and kinetically controlled reactions requires additional input data. Unlike groundwater flow and transport models, thermodynamic models, in principal, do not need any calibration. However, considering surface-controlled or kinetically controlled reaction models might be subject to calibration. Typical problems for the application of geochemical models are: • speciation • determination of saturation indices • adjustment of equilibria/disequilibria for minerals or gases • mixing of different waters • modeling the effects of temperature • stoichiometric reactions (e.g. titration) • reactions with solids, fluids, and gaseous phases (in open and closed systems) • sorption (cation exchange, surface complexation) • inverse modeling • kinetically controlled reactions • reactive transport Hydrogeochemical models depend on the quality of the chemical analysis, the boundary conditions presumed by the program, theoretical concepts (e.g.

This book invites the reader to look differently at two seemingly mundane resources: soil and water. Water possesses extraordinary properties which form the foundations of life itself. Without water, there would be no life, and without soils, no terrestrial life. The interaction between soils and water is therefore fundamental to the habitability of Earth’s land surface. Through in-depth analyses and experimentation, Soils as a Key Component of the Critical Zone 3 explores the circulation of water in soils. Through its properties, soil directs the path of water, leading it to wet soils or not, be absorbed by plants, infiltrate or runoff, concentrate in certain areas or flood. The potentially catastrophic consequences of such floods are often due to the absence or insufficiency of prevention measures. This book thus shows the ways in which the relationship between water, life and soils is much more than a simple series of interactions or phenomena at interfaces and in fact constitutes a system with definite properties.

Corrosion of Reinforced Concrete Structures: Mechanism, Monitoring and Control presents research, theory and practice on the control of corrosion in reinforced concrete structures. The title is a comprehensive guide to corrosion, its monitoring and prevention in reinforced concrete structures. It considers the essential mechanisms of corrosion, provides key monitoring techniques, describes how to effectively control corrosion, and how to establish a cyber-physical protection system. As corrosion is one of the most significant factors in the deterioration of civil engineering structures globally, and with concrete the world's most utilized manufactured material, this book highlights strategies to keep corrosion from becoming a serious threat. - Focuses on corrosion in reinforced concrete structures - Presents the mechanisms involved in the corrosion of reinforced concrete - Provides guidance on the assessment of corrosion and methods of corrosion control - Details how to set up an effective cyber-physical-system to protect reinforced concrete structures - Collates and presents the latest research from multiple disciplines on corrosion in reinforced concrete structures

Open system behavior is predicated on a fundamental relationship between the timescale over which mass is transported and the timescale over which it is chemically transformed. This relationship describes the basis for the multidisciplinary field of reactive transport (RT). In the 20 years since publication of Review in Mineralogy and Geochemistry volume 34: Reactive Transport in Porous Media, RT principles have expanded beyond early applications largely based in contaminant hydrology to become broadly utilized throughout the Earth Sciences. RT is now employed to address a wide variety of natural and engineered systems across diverse spatial and temporal scales, in tandem with advances in computational capability, quantitative imaging and reactive interface characterization techniques. The present volume reviews the diversity of reactive transport applications developed over the past 20 years, ranging from the understanding of basic processes at the nano- to micrometer scale to the prediction of Earth global cycling processes at the watershed scale. Key areas of RT development are highlighted to continue advancing our capabilities to predict mass and energy transfer in natural and engineered systems.