scholarly journals Autogenous Healing of Early-Age Cementitious Materials Incorporating Superabsorbent Polymers Exposed to Wet/Dry Cycles

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2476 ◽  
Author(s):  
Yewon Shim ◽  
Geuntae Hong ◽  
Seongcheol Choi

This study experimentally investigated the autogenous healing performances of cementitious materials incorporating superabsorbent polymers (SAPs) after exposure to eight cycles of wet/dry conditions. In each cycle, cracked cement paste specimens with different SAP dosages were exposed to wet conditions for 1 h, during which capillary water absorption tests were conducted, and then exposed to dry conditions for 47 h. The test results reveal that the initial sorptivity values of the reference, 0.5% SAP, 1.0% SAP, and 1.5% SAP specimens after one cycle were decreased by 22.9%, 36.8%, 42.8%, and 46.3%, respectively, after eight cycles. X-ray micro-computed tomography analysis showed that the crack volume percentages filled with healing products were 1.1%, 1.6%, 2.2%, and 2.9% in the reference, 0.5% SAP, 1.0% SAP, and 1.5% SAP specimens, respectively. As the cycling was repeated, the reduction ratio of the initial sorptivity and the quantity of healing products were increased with increases in SAP dosage. Furthermore, more healing products were distributed near SAP voids than in other sections in the specimens. This study demonstrates that the incorporation of SAPs in cementitious materials can enhance the autogenous healing performances of materials exposed to cyclic wet/dry conditions.

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Huashan Yang ◽  
Yujun Che

Ground phosphorous slag (PS) has not been widely used in construction due to its negative effects on the early-age performances of cementitious materials. The effects of calcium carbonate nanoparticles (NC) on strength development of mortar containing high content of PS were investigated at different curing ages. The NC was incorporated at 2% as partial mass replacements for binder. Hydration products and microstructure characterization was examined by X-ray diffraction (XRD), differential thermal gravity (DTG), thermogravimetric (TG), and scanning electron microscopy (SEM) analysis. Test results showed that NC improved both flexural and compressive strength of mortar containing high content of PS at 7, 28, 56, and 90 days. XRD, DTG-TG, and SEM analysis confirmed the filling effect of NC. Furthermore, the formation of the carboaluminate even at later age also improved the microstructure of mortar, which created a denser microstructure.


2021 ◽  
Vol 35 ◽  
pp. 102059
Author(s):  
J. Van Der Putten ◽  
D. Snoeck ◽  
R. De Coensel ◽  
G. De Schutter ◽  
K. Van Tittelboom

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 208
Author(s):  
Xu Chen ◽  
Youlai Zhang ◽  
Shaochun Li ◽  
Yongjuan Geng ◽  
Dongshuai Hou

Through penetration depth tests, capillary water absorption tests under different abrasion depths, and capillary water absorption tests of a cement mortar test block with crack damage, a self-prepared, novel, graphene oxide/silane composite emulsion used for the effect of wear or cracking damage was studied. The waterproof performance of concrete and the protective mechanism of a composite emulsion was verified by scanning electron microscopy, X-ray diffraction, and thermogravimetric analysis. The test results showed that the penetration depth of the composite emulsion reached depths greater than 9 mm, which yielded a good waterproof effect; when the concrete was cracked or worn, the composite emulsion still had a stable waterproof performance. It was found that the composite emulsion could form a hydrophobic layer with a certain thickness inside the cement-based material, which explains why the composite emulsion had a good waterproof effect.


2019 ◽  
Vol 70 (11) ◽  
pp. 1977-1998 ◽  
Author(s):  
Mohammed Albahri ◽  
Ahmed Barifcani ◽  
Deepak Dwivedi ◽  
Stefan Iglauer ◽  
Maxim Lebedev ◽  
...  

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 690
Author(s):  
Geuntae Hong ◽  
Chiwon Song ◽  
Seongcheol Choi

The effect of superabsorbent polymers (SAPs) on autogenous crack healing in cementitious materials with early-age cracking was investigated. SAP-containing samples exposed to wet/dry cycles showed better autogenous healing than those only exposed to wet conditions, as determined by water flow and compressive strength recovery tests. The water flow rates through cracks (380 ± 40 µm) in cement paste and cement mortar containing 1.0% SAP decreased by around 97.1–100% and 79.7–90.7%, respectively, after 14 cycles of healing compared to 1 cycle. Although the initial compressive strength decreased with SAP addition, it recovered somewhat after a 28-d healing period. Microscopy and spectroscopy results identified CaCO3 and/or calcium silicate hydrate (CSH) as the main healing products.


2014 ◽  
Vol 33 (4) ◽  
pp. 476-483 ◽  
Author(s):  
Yukihiko TAKEMURA ◽  
Koji HANAOKA ◽  
Ryota KAWAMATA ◽  
Takashi SAKURAI ◽  
Toshio TERANAKA

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