Anti-water-penetration techniques are important to raise the durability of cement-based materials (CBMs). Here the water penetration resistances of cement mortars with ethylene-vinyl acetate copolymer (EVA) and styrene butadiene rubber (SBR) were in-situ and non-destructively probed by micro-focus X-ray computed tomography (μ-XCT). Caesium Chloride (CsCl) was mixed in water to enhance the contrast gradients of μ-XCT images. SEM and EDS tests were provided to assess the mortar microstructure changes induced by water penetration. Results show that the CsCl enhancement helps trace the water penetration fronts, while exerting minor influences on the water penetration kinetics. The polymers can greatly raise the resistance against the water penetration into the cement mortars. The pore blocking induced by the formation of polymer films on the surfaces of cement grains and aggregates may account for the enhanced water-penetration resistance. The findings of this work provide a new method to track the water penetration in CBMs by μ-XCT and deepen the knowledge in the anti-water mechanisms of polymer-modified cement materials.

In-situ assessment of the water-penetration resistance of polymer modified cement mortars by μ-XCT, SEM and EDS

It is a challenge to isolate the ITZ effect on the mass transport from several concurrent factors. This study designed a systematical experimental work to assess the relatively importance of ITZ to gas permeability, capillary water absorption and chloride migration, considering the effect of preconditioning regime, aggregate volume content and size. The ratio of mass transport between ITZ and bulk cement matrix was given against ITZ thickness. Besides the dilution and tortuosity, factors such as densification of bulk cement matrix, bleeding along coarse aggregate should also be considered in the analysis of ITZ effect. The densification effect and ITZ effect would be more prominent with a higher aggregate content or finer aggregate size. The sorptivity is less while chloride migration is more sensitive to the variation of ITZ. The cracks due to precondition could mislead the analyzing ITZ effect, which is also dependent on the type of transport. This study is expected to offer more insight into the effect of certain components on the performance of concrete.

Experimental study on concurrent factors influencing the ITZ effect on mass transport in concrete

Influence of different curing methods on the compressive strength of ultra-high-performance concrete: A comprehensive review

Rice hush ash as supplementary cementitious material for calcium aluminate cement – Effects on strength and hydration

Surface properties of clay brick powder and its influence on hydration and strength development of cement paste

The improvement of freezing–thawing resistance of concrete by cellulose/polyvinyl alcohol hydrogel

In order to modify the porous interfacial transition zone (ITZ) microstructure of concrete more efficiently, a method of coating aggregate surfaces by using several nanoparticles was evaluated in this study. The compressive strength, chloride penetration of sound, and pre-loading samples were assessed in relation to the type of coating materials used (slag, nano-CaCO3, and nano-SiO2) and the designed coating thickness (5, 10, and 15 μm). The ITZ microstructure was quantitatively determined via Backscattered electron (BSE) image analysis. Results showed that the overall performance of concrete is highly dependent on the coating materials and the designed coating thickness. Increasing the coating thickness of slag and nano-SiO2 could improve the chloride penetration resistance but decrease the compressive strength. Using nano-CaCO3 to coat the aggregate leads to a significant reduction in the properties of the so-prepared concrete. Though coating inert fine particles around aggregate could disturb the initial particle packing and modify the ITZ, it is not able to improve the overall concrete properties. Coating aggregate could determine the ITZ microstructure, especially within the region that is around 30 μm away from aggregate surface.

https://www.mdpi.com/1996-1944/12/21/3541/pdf

Supported ITZ Modification Efficiencies via Surface Coating Nanoparticles on Aggregate and its Influence on Properties.

As the population ages, spinal degeneration seriously affects quality of life in middle-aged and elderly patients, and prevention and treatment remain challenging for clinical surgeons. In recent years, biomaterials-based injectable therapeutics have attracted much attention for spinal degeneration treatment due to their minimally invasive features and ability to perform precise repair of irregular defects. However, the precise design and functional control of bioactive injectable biomaterials for efficient spinal degeneration treatment remains a challenge. Although many injectable biomaterials have been reported for the treatment of spinal degeneration, there are few reviews on the advances and effects of injectable biomaterials for spinal degeneration treatment. This work reviews the current status of the design and fabrication of injectable biomaterials, including hydrogels, bone cements and scaffolds, microspheres and nanomaterials, and the current progress in applications for treating spinal degeneration. Additionally, registered clinical trials were also summarized and key challenges and clinical translational prospects for injectable materials for the treatment of spinal degenerative diseases are discussed. 

https://doi.org/10.1016/j.mtbio.2022.100336

Hao Han

Papers

Experimental study on concurrent factors influencing the ITZ effect on mass transport in concrete

The improvement of freezing–thawing resistance of concrete by cellulose/polyvinyl alcohol hydrogel

Rice hush ash as supplementary cementitious material for calcium aluminate cement – Effects on strength and hydration

Supported ITZ Modification Efficiencies via Surface Coating Nanoparticles on Aggregate and its Influence on Properties.

Precision medicine strategies for spinal degenerative diseases: Injectable biomaterials with in situ repair and regeneration