Self-healing cement composite: Amine- and ammonium-based pH-sensitive superabsorbent polymers

Wang, Chunyu; Bu, Yuhuan; Guo, Shenglai; Lu, Yao; Sun, Baojiang; Shen, Zhonghou

doi:10.1016/j.cemconcomp.2018.11.023

Cited by 37 publications

(13 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been reported that SAPs can reduce the permeability of water through cracks when cracks occur in cement composites [3,4,5,6]. It also has been reported that SAPs heal cracks by supplying moisture to cement composites [7,8,9,10]. …”

Section: Introductionmentioning

confidence: 99%

Influence of Effective Water-to-Cement Ratios on Internal Damage and Salt Scaling of Concrete with Superabsorbent Polymer

et al. 2019

View full text Add to dashboard Cite

Superabsorbent polymer (SAP) is attracting attention as a water-entraining admixture that reduces shrinkage or heals cracks in concrete. Cross-linked sodium polyacrylate SAPs, which are the most widely produced SAPs in the global market, are applicable as concrete admixtures. However, there have been contradictory results on the freeze–thaw resistance of concrete with SAPs. This study aims to clarify these results considering the water absorption behavior of SAPs in hardened concrete when effective water-to-cement ratios are different. Firstly, the absorbencies of one kind of cross-linked sodium polyacrylate SAP (SAP_SP) in pore solution and fresh mortar were measured by a tea bag test and flow test, respectively. Pore size distribution, capillary water absorption, and deformation during freeze–thaw cycles were analyzed for mortar samples with varying SAP_SP dosages. In the main tests, concrete samples with three different SAP_SPs/cement ratios (0.1%, 0.2%, and 0.3%) and a reference sample were prepared, and internal damage and salt scaling were measured under freeze–thaw cycles. Because SAP_SP absorbs water in fresh mixtures, additional water was added to the mixture considering the water absorbency of the SAP_SP. It was found that the used SAP_SPs prematurely release their stored water so the effective water-to-cement ratio was increased when a larger amount of SAP_SP was used. The higher effective water-to-cement ratio caused more internal damage and salt scaling due to the weaker cementitious matrix. In addition, mortar samples with a high SAP_SP content show a larger absorption of capillary water than the reference sample. The result can be interpreted by an observation that SAP_SP in air voids absorbs water and expands to relatively large capillary pores or neighbor air voids during the capillary water absorption process.

show abstract

Section: Introductionmentioning

confidence: 99%

Influence of Effective Water-to-Cement Ratios on Internal Damage and Salt Scaling of Concrete with Superabsorbent Polymer

et al. 2019

View full text Add to dashboard Cite

show abstract

“…The use of SAPs has also been explored in combination with expansive agents such as calcium sulfoaluminate in sulfur composites [137]. The stimulated autogenous healing has also been studied in specimens containing pHsensitive SAPs or natural polymers in combination with a synthetic backbone [79,80,82,85,138]. In order to further increase the amount of calcium carbonate precipitation in a wide crack of several hundreds of micrometers, SAPs can be combined with bacteria [139,140].…”

Section: Regaining the Mechanical Properties Due To Promoted Autogenous Healingmentioning

confidence: 99%

5 Superabsorbent polymers as a solution for various problems in construction engineering

Snoeck¹

2021

Superabsorbent Polymers

View full text Add to dashboard Cite

One of the most-used man-made materials is concrete, a mixture of cement, sand, aggregates, water, and admixtures. It can be seen everywhere: in tunnels, bridges, and high-rise buildings. Ever since concrete was rediscovered two centuries ago, it has been studied in detail in order to optimize the material and to solve its inherent problems. Most people know that concrete is gray, hard, and strong, and expect it to last decades and even centuries. Unfortunately, this is not always the case. Concrete is a material which can cope with high compressive forces but when it is subjected to tensile forces, it may crack. This cracking is based on several environmental and loading conditions, but the fact that concrete is prone to crack is a big issue. When cracking occurs and potentially harmful substances enter the interior of concrete, the concrete matrix may be damaged and even be destroyed. That is the reason why a lot of maintenance and repair works are due in order to increase the durability and lifetime of structures in civil engineering. One way of dealing with these issues is the modification of the material itself, making it less prone to cracking and the durability-related consequences. An example is the use of reinforcements, coping with the tensile forces when concrete cracks. Cracks are not harmful but intruding substances may trigger the corrosion of the iron rebars leading to structural failure, which is again unwanted. In consequence, along the history, different materials were investigated and added to concrete to solve the previous adverted problems. So, why not try adding the white powder superabsorbent polymers in the cementitious material in order to solve these issues?

show abstract

“…In concrete, first, SAPs absorb water and expand when water enters a crack, and then, the expanded SAPs seal the crack, thus preventing harmful ions from entering the matrix [20]. Second, under dry conditions, the water absorbed by the SAPs is released to the surfaces of the cracks, which promotes hydration of unhydrated cement particles, thus sealing the crack [21,22]. Thus, SAPs show potential for use as self-healing agents in mortar and concrete.…”

Section: Introductionmentioning

confidence: 99%

Improving Self-Healing and Shrinkage Reduction of Cementitious Materials Using Water-Absorbing Polymer Microcapsules

Mao

Chen

et al. 2022

Materials

View full text Add to dashboard Cite

Self-healing cementitious materials are a promising means for ensuring sustainable concrete infrastructure and promoting long-term service lives. To obtain microcapsules that are versatile in varying environments, in this study, absorbing microcapsules with calcium alginate as the shell and epoxy resin as the core were prepared. The absorbing microcapsules exhibit self-healing and can reduce the shrinkage of cementitious materials. Volume changes of the microcapsules in the hardened paste with increasing hydration age were observed using three-dimensional X-ray computed tomography. In the hardened cement paste with a water-cement ratio of 0.29, the absorption of the microcapsules lasted for several days, and the release of water lasted for 28 days. The absorption of microcapsules affected the fluidity of cement paste, and it was significantly weakened and delayed due to the lower absorption rate. The addition of absorbing microcapsules significantly reduced the autogenous and drying shrinkage of mortars. For microcapsules with a core content of 55% added at 3.5% of cement weight, autogenous shrinkage was almost eliminated. Most importantly, the addition of absorbing microcapsules could achieve a certain degree of recovery of compressive strength as well as satisfactory recovery of impermeability in dry and wet environments.

show abstract

Self-healing cement composite: Amine- and ammonium-based pH-sensitive superabsorbent polymers

Cited by 37 publications

References 32 publications

Influence of Effective Water-to-Cement Ratios on Internal Damage and Salt Scaling of Concrete with Superabsorbent Polymer

Influence of Effective Water-to-Cement Ratios on Internal Damage and Salt Scaling of Concrete with Superabsorbent Polymer

5 Superabsorbent polymers as a solution for various problems in construction engineering

Improving Self-Healing and Shrinkage Reduction of Cementitious Materials Using Water-Absorbing Polymer Microcapsules

Contact Info

Product

Resources

About