Quantitative characterisation of absorption capacity and dosage of SAP in cement paste

The application of self-healing concrete for durability enhancement has become a widely studied topic in recent decades. This paper focuses on addition of a superabsorbent polymer (SAP) to bio-based self-healing concrete – a material in which cracks are autonomously sealed by incorporated microorganisms. As previously proposed, the SAP could serve as protection of the microorganisms against the harsh concrete environment and possibly to further enhance the materials autogenous sealing capacity. However, determining the applicable bio-based concrete mix design is not without obstacles as the immense absorption capacity of the SAP is, inter alia, closely related to ions present in the solution. This current study compares different mix designs of cement paste with the nutrients applied in the bio-based concrete and the addition of the SAP in dry and partially saturated states. The paste consistencies are determined, and a number of cement paste specimens is prepared to measure flexural and compressive strengths at 7 and 28 days from casting. The flowability results indicate that the SAP in a dry state absorbs slightly less than 25 g/g SAP of extra mixing water as the final consistency was similar to the reference paste. Further, the results showed that the partially saturated SAP is able to retain a great amount of the liquid throughout the mixing process. In this study, the strengths generally drop by still admissible 20% in the case of the dry SAP and extra water addition, whereas the replacement of mixing water by the partially saturated SAP results in a significant strength increase. These findings indicate that the dosage 0.5% SAP by cement weight in both of the states, dry and saturated, is applicable in the nutrient enriched cement paste from the mechanical perspective, although further work which would describe the absorption and retention mechanisms in depth is needed.

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Quantitative characterisation of steel/cement paste interface microstructure and corrosion phenomena in mortars suffering from chloride attack

Corrosion Science ◽

10.1016/j.corsci.2006.03.003 ◽

2006 ◽

Vol 48 (12) ◽

pp. 4001-4019 ◽

Cited By ~ 45

Author(s):

D.A. Koleva ◽

J. Hu ◽

A.L.A. Fraaij ◽

P. Stroeven ◽

N. Boshkov ◽

...

Keyword(s):

Cement Paste ◽

Interface Microstructure ◽

Chloride Attack ◽

Quantitative Characterisation

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Immobilization of Bacterial Cells on Natural Minerals for Self-Healing Cement-Based Materials

Frontiers in Built Environment ◽

10.3389/fbuil.2021.655935 ◽

2021 ◽

Vol 7 ◽

Author(s):

Ilgin Sandalci ◽

Mustafa Mert Tezer ◽

Zeynep Basaran Bundur

Keyword(s):

Water Absorption ◽

Cement Paste ◽

Healing Process ◽

Pulse Velocity ◽

Absorption Capacity ◽

Water Absorption Capacity ◽

Bacterial Cells ◽

Self Healing ◽

Calcium Carbonate Precipitation ◽

Main Challenge

Recent research in the field of concrete materials showed that it might be possible to develop a smart cement-based material that is capable of remediating cracks by Microbial-induced calcium carbonate precipitation (MICP). The early remediation of microcracks enables the design of cement-based systems with an elongated service life with a sustainable approach. However, the main challenge of the application is to extend the viability of the cells against the restrictive environment of cement-paste. These cells have to tolerate the highly alkaline conditions of cement paste, survive the mixing process, and remain viable even when access to nutrients is limited. This paper summarizes a novel study undertaken to investigate the self-healing efficiency of Sporosarcina pasteurii (S. pasteurii) cells immobilized on zeolite and sepiolite minerals having the same particle size. This manuscript reports an extensive experimental study to understand the factors influencing the efficiency of immobilization barriers, such as composition and reactivity. To obtain the bio-additive, the bacterial cells were immobilized without nutrients and additional nutrients were only provided during the curing stage after crack initiation. Screening of the healing process was done with ultrasonic pulse velocity (UPV) testing and stereomicroscopy. Further evaluation on performance was done by evaluating the decrease in water absorption capacity. The healing precipitate was characterized through Environmental Scanning Electron Microscope (ESEM) and Fourier-Transform infrared spectroscopy (FTIR). With this approach, the cracks on mortar surface were sealed and the water absorption capacity of the so-called self-healed mortar decreased compared to its counterpart cracked mortar samples. Sepiolite was found to be a more suitable bedding for the microorganisms compared to zeolite, therefore samples containing sepiolite exhibited a higher performance in terms of crack healing. The results showed that while vegetative cell immobilization on locally available materials is a simple and economically feasible approach the healing capacity of bacterial cells can be hindered due to the reactivity of the mineral.

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EVALUATION OF ABSORPTION CAPACITY AND SPATIAL DISTRIBUTION OF SUPERABSORBENT POLYMER IN CEMENT PASTE

Cement Science and Concrete Technology ◽

10.14250/cement.73.451 ◽

2020 ◽

Vol 73 (1) ◽

pp. 451-458

Author(s):

Soshi YAMASHITA ◽

Shin-ichi IGARASHI

Keyword(s):

Spatial Distribution ◽

Cement Paste ◽

Absorption Capacity ◽

Superabsorbent Polymer

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Energy Absorption Capacity of SBR Latex-Modified Ordinary Portland Cement by Charpy Impact Test

Materials ◽

10.3390/ma14102544 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2544

Author(s):

Tri N. M. Nguyen ◽

Jung-J. Kim

Keyword(s):

Compressive Strength ◽

Energy Absorption ◽

Cement Paste ◽

Impact Test ◽

Charpy Impact ◽

Charpy Impact Test ◽

Absorption Capacity ◽

Styrene Butadiene Rubber ◽

Butadiene Rubber ◽

Energy Absorption Capacity

The present study deals with tests on the energy absorption capacity and compressive strength of styrene–butadiene rubber (SBR) latex-modified cementitious materials. Different polymer–cement ratios (P/C) of 0, 5, 10, 15, and 20% were carried out with the Charpy impact test at 7, 14, and 28 days of curing. The observations showed an increase in the energy absorption capacity of the SBR latex-modified cement paste in correspondence with the increase in curing times, as well as the increase in the P/C ratios. The P/C ratio of 10% was the optimal ratio for observing the highest energy absorption capacity of the SBR latex-modified cement paste, with a 43% increase observed. In addition, a linear relationship between compressive strength and the energy absorption capacity at 28 days was proposed. Based on that, the energy absorption capacity of SBR latex-modified cement paste can be analyzed or predicted by the compressive strength results, regardless of the P/C ratios. Finally, the two-parameter Weibull distribution was proved to fit by the observation data from the Charpy impact test.

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