Self-healing is a natural phenomenon whereby living organisms respond to damage. Recently, considerable research efforts have been invested in self-healing cementitious materials that are capable of restoring structural integrity and mechanical properties after being damaged. Inspired by nature, a variety of creative approaches are explored here based on the intrinsic or extrinsic healing mechanism. Research on new intrinsic self-healing cementitious materials with biomimetic features is on the forefront of material science, which provides a promising way to construct resilient and sustainable concrete infrastructures. Here, the current advances in the development of the intrinsic healing cementitious materials are described, and a new definition of intrinsic self-healing discussed. The methods to assess the efficiency of different healing mechanisms are briefly summarized. The critical insights are emphasized to guide the future research on the development of new self-healing cementitious materials.

Recent Advances in Intrinsic Self-Healing Cementitious Materials.

The Hanford site in Washington State houses ~56 million gallons of radioactive wastes stored in 177 underground tanks. The waste must be immobilized and permanently stored, and the plan is to separate the tank wastes into low activity waste (LAW) and high-level waste (HLW) streams. The U.S. Department of Energy is building a Waste Treatment and Immobilization Plant at Hanford site to separately vitrify these two waste streams in borosilicate glass using Joule-heated ceramic melters (JHCM). Although the process of nuclear waste vitrification seems to be well established, in practicality, it is faced with complex problems starting from the design of glass compositions, to processing in melters and long-term performance of the final vitrified waste forms. The article presents an overview of our current understanding of critical challenges related to the development and performance of HLW glasses.

Challenges with vitrification of Hanford High-Level Waste (HLW) to borosilicate glass – An overview

A Game Changer: Functional Nano/Micromaterials for Smart Rechargeable Batteries

Concrete is a very common material consisting of a mixture of aggregates (sand, gravel, crashed rock) and paste (cement, water and additives). The paste component, made up mainly of cement and water, degrades with time. Despite this shortcoming, research toward the next-generation cement and concrete materials has intensified in the past 10–15 years. Self-healing cementitious materials, in particular, are a research area that has attracted a great deal of attention. A number of novel formulations have demonstrated an increase in mechanical and chemical stability with respect to conventional Portland cement, through the addition of inorganic, organic, and even biological additives. This review reports on the latest developments in cement research related to the synthesis of cement and concrete materials with autogenous healing and/or self-healing capability. These include geopolymers, engineered cementitious materials, bacterial cement composites, microencapsulated self-healing materials, self-healing assisted by shape-memory alloys, and polymer–cement composites. This work describes the performance of each cementitious material and the mechanism responsible for healing, including a section on atomistic simulations and modeling of cementitious materials. A detailed understanding of various cement technologies with autogenous healing and self-healing properties, including their strengths and weaknesses, is critical to determine the areas where new development is needed to enable novel, energy-efficient, and environmentally responsible cement and concrete solutions. To this end, molecular simulations can play a significant role and have already demonstrated promise in achieving an atomic level view of interactions between cementitious materials and other add-on compounds, such as carbon nanotubes or polymers for enhanced reinforcement or autonomous healing properties. Next-generation construction materials are led by self-healing cement and concrete. With a wide range of autonomous healing strategies based on smart polymers and alloys, biotechnology, and molecular modeling, advanced cementitious materials are becoming part of our daily lives. This work represents a comprehensive review on progress, challenges, and opportunities in the development of these materials for infrastructure and beyond.

Progress and challenges in self-healing cementitious materials

Motivated by recent advances in self-healing cement and epoxy polymer composites, we present a combined ab initio molecular dynamics and sum frequency generation (SFG) vibrational spectroscopy study of a calcium–silicate–hydrate/polymer interface. On stable, low-defect surfaces, the polymer only weakly adheres through coordination and hydrogen bonding interactions and can be easily mobilized toward defected surfaces. Conversely, on fractured surfaces, the polymer strongly anchors through ionic Ca–O bonds resulting from the deprotonation of polymer hydroxyl groups. In addition, polymer S–S groups are turned away from the cement–polymer interface, allowing for the self-healing function within the polymer. The overall elasticity and healing properties of these composites stem from a flexible hydrogen bonding network that can readily adapt to surface morphology. The theoretical vibrational signals associated with the proposed cement–polymer interfacial chemistry were confirmed experimentally by SFG vibrationa...

Atomic Origins of the Self-Healing Function in Cement–Polymer Composites

Sealing of wellbores in geothermal and tight oil/gas reservoirs by filling the annulus with cement is a well-established practice. Failure of the cement as a result of physical and/or chemical stress is a common problem with serious environmental and financial consequences. Numerous alternative cement blends have been proposed for the oil and gas industry. Most of these possess poor mechanical properties, or are not designed to work in high temperature environments. This work reports on a novel polymer-cement composite with remarkable self-healing ability that maintains the required properties of typical wellbore cements and may be stable at most geothermal temperatures. We combine for the first time experimental analysis of physical and chemical properties with density functional theory simulations to evaluate cement performance. The thermal stability and mechanical strength are attributed to the formation of a number of chemical interactions between the polymer and cement matrix including covalent bonds...

Polymer-Cement Composites with Self-Healing Ability for Geothermal and Fossil Energy Applications

Rheology of simulated radioactive waste slurry and cold cap during vitrification

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Gas Retention, Gas Release, and Fluidization of Spherical Resorcinol-Formaldehyde (sRF) Ion Exchange Resin

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Diana T. Linn

Papers

Polymer-Cement Composites with Self-Healing Ability for Geothermal and Fossil Energy Applications

Rheology of simulated radioactive waste slurry and cold cap during vitrification

Gas Retention, Gas Release, and Fluidization of Spherical Resorcinol-Formaldehyde (sRF) Ion Exchange Resin

Standard High Solids Vessel Design De-inventory Simulant Qualification