scholarly journals Feasibility of Using 3D Printed Polyvinyl Alcohol (PVA) for Creating Self-Healing Vascular Tunnels in Cement System

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3872 ◽  
Author(s):  
Zijing Li ◽  
Lívia Ribeiro de Souza ◽  
Chrysoula Litina ◽  
Athina E. Markaki ◽  
Abir Al-Tabbaa
Keyword(s):  
Polyvinyl Alcohol ◽  
Early Stage ◽  
Cementitious Materials ◽  
Self Healing ◽  
Vascular Networks ◽  
X Ray Diffraction ◽  
Cement Pastes ◽  
Polymer Compound ◽  
3D Printed

Pursuing long-term self-healing infrastructures has gained popularity in the construction field. Vascular networks have the potential to achieve long-term self-healing in cementitious infrastructures. To avoid further monitoring of non-cementitious tubes, sacrificial material can be used as a way of creating hollow channels. In this research, we report a new method for fabrication of complex 3D internal hollow tunnels using 3D printing of polyvinyl alcohol (PVA). The behaviour of 3D printed PVA structures in cement pastes was investigated using computed-tomography (CT) combined with X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDX). Results showed that (i) 1300 min were needed to fully dissolve 1 g of a 3D printed PVA structure, and different pH solutions did not significantly change the PVA dissolving process compared with a neutral environment; (ii) a low water/cement ratio can minimize early stage cracking resulting from PVA expansion; (iii) and PVA-cement interaction products were mainly calcite and a Ca-polymer compound. In conclusion, controlling the PVA expansion by decreasing the water/cement (w/c) ratio provides a promising approach to achieve 3D hollow channels in cement and, therefore, makes it possible to create complex tunnels within self-healing cementitious materials.

scholarly journals Development of 3D Printed Networks in Self-Healing Concrete

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1328 ◽  
Author(s):  
Cristina De Nardi ◽  
Diane Gardner ◽  
Anthony Duncan Jefferson
Keyword(s):  
Vascular System ◽  
Physical And Mechanical Properties ◽  
Self Healing ◽  
Vascular Networks ◽  
Minimal Impact ◽  
Cementitious Matrix ◽  
Healing Agent ◽  
3D Printed ◽  
Series Of Experiments ◽  
Concrete Elements

This paper presents a new form of biomimetic cementitious material, which employs 3D-printed tetrahedral mini-vascular networks (MVNs) to store and deliver healing agents to damage sites within cementitious matrices. The MVNs are required to not only protect the healing agent for a sufficient period of time but also survive the mixing process, release the healing agent when the cementitious matrix is damaged, and have minimal impact on the physical and mechanical properties of the host cementitious matrix. A systematic study is described which fulfilled these design requirements and determined the most appropriate form and material for the MVNs. A subsequent series of experiments showed that MVNs filled with sodium silicate, embedded in concrete specimens, are able to respond effectively to damage, behave as a perfusable vascular system and thus act as healing agent reservoirs that are available for multiple damage-healing events. It was also proved that healing agents encapsulated within these MVNs can be transported to cracked zones in concrete elements under capillary driving action, and produce a recovery of strength, stiffness and fracture energy.

Sandwich-like polyvinyl alcohol (PVA) grafted graphene: A solid-inhibitors container for long term self-healing coatings

2020 ◽  
Vol 383 ◽  
pp. 123203 ◽  
Author(s):  
Yunan Lin ◽  
Rongrong Chen ◽  
Yanjun Zhang ◽  
Zhu Lin ◽  
Qi Liu ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Self Healing

SYNTHESIS AND CHARACTERIZATION OF SELF-HEALING MORTAR WITH MODIFIED STRENGTH

2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Gassan Fahim Huseien ◽  
Jahangir Mirza ◽  
Nur Farhayu Ariffin ◽  
Mohd Warid Hussin
Keyword(s):  
Early Stage ◽  
Polymeric Materials ◽  
Building Blocks ◽  
Ultrasonic Pulse Velocity ◽  
Cementitious Materials ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Diglycidyl Ether ◽  
Self Healing ◽  
Research Initiative

Cementitious materials being the most prospective building blocks achieving their absolute strength to avoid the deterioration in the early stage of service life is ever-demanding. Minimizing the labor and capital-intensive maintenance and repair cost is a critical challenge. Thus, self-healing mortars with modified strength are proposed. Lately, self-healing of micro-cracks by introducing bacteria during the formation of mortar or concrete became attractive. Self-healing with polymeric admixtures is considered to be relatively more durable and faster process. Certainly, the self-healing of synthetic polymeric materials is inspired by biological systems, where the damage triggers an autonomic healing response. This emerging and fascinating research initiative may significantly improve the durability and the safety limit of the polymeric components potential for assorted applications. In this work, using epoxy resin (diglycidyl ether of bisphenol A) without any hardener as admixture polymeric-cementitious materials is prepared. These epoxy-modified mortars are synthesized with various polymer-cement ratios subjected to initial wet/dry curing (WDC) together with long term dry curing (DC). Their self-healing function and hardening effects are evaluated via preloading and drying of the specimens, chemical analysis, and ultrasonic pulse velocity testing. It is demonstrated that 10% of polymer is the best proportion for polymer-cement ratio. Furthermore, the wet/dry curing is established to be superior process for healing hairline cracks present in the mortar. The excellent features of the results suggest that our novel method may constitute a basis for improving the compressive strength and self-healing features of mortars.    

A Novel Approach to Characterize the Quantity and Distribution of Microorganisms in Microbial Self-Healing Cementitious Materials

2021 ◽  
Vol 871 ◽  
pp. 386-391
Author(s):  
Qin Wen Chen ◽  
Chun Xiang Qian
Keyword(s):  
Calcium Carbonate ◽  
Cementitious Materials ◽  
Self Healing ◽  
Activity Change ◽  
Cement Pastes ◽  
Effector Cells ◽  
Specific Distribution ◽  
Novel Approach ◽  
Linear Fit ◽  
The Relationship

Microorganisms can effectively heal the cracks of cementitious materials through the formation of calcium carbonate by microbial mineralization deposition, which has a wide application prospect in cementitious materials. In order to analysis the activity change and distribution of microorganisms in cementitious materials, this paper prepared cement pastes incorporated microbial powder, and extracted microorganisms by pre-crushing, grinding and ultrasonic, at the age of 3, 7 and 28 days respectively. The relationship between the optical density and effector cells is near linear fit, reflecting the activity change and specific distribution of microorganisms in cement paste specimen of different ages. The in-depth research on the activity change and distribution of microorganisms in the microbial cementitious materials can effectively characterize the microorganisms in the cementitious materials, which has a guiding role in microbial self-healing cementitious materials.

scholarly journals Crack-healing in cementitious material to improve the durability of structures: Review

2018 ◽  
Vol 250 ◽  
pp. 03005 ◽  
Author(s):  
Hassan Amer Ali Algaifi ◽  
Suhaimi Abu Bakar ◽  
Abdul Rahman Mohd Sam ◽  
Ahmad Razin Zainal Abidin
Keyword(s):  
Crack Width ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Self Healing ◽  
Crack Healing ◽  
Harmful Substances ◽  
Crack Faces ◽  
Crack Widths ◽  
Long Term Studies

One of the most commonly used materials in the field of construction is concrete. Nevertheless, there are strong inclinations for concrete to form cracks, which would then allow the penetration of both aggressive and harmful substances into the concrete. Subsequently, this will decrease the durability of the affected structures. Thus, the ability for cracks to heal themselves in the affected cementitious materials is in demand to prolong the life of any structure. Autogenous self-healing is one approach to overcome smaller crack widths (macrocracks). Nowadays, crack width-healing is of great importance. Having said that, both polymers and bacteria are the most common approach to enhance autogenous self-healing and bond crack faces. Crack width-healing of up to 0.97 mm was achieved via bacteria-based self-healing. In this paper, the mechanisms of these approaches and their efficiency to heal crack were highlighted. Both bacteria-and polymers-based self-healing are promising techniques for the future. However, long term studies are still required before real applications can be made.

Pozzolanic Reaction of Supplementary Cementitious Materials and Its Effects on the Strength of Mass Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 505-511 ◽  
Author(s):  
Hua Shan Yang ◽  
Kun He Fang ◽  
Sheng Jin Tu
Keyword(s):  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Supplementary Cementitious Materials ◽  
Mass Concrete ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slag Powder ◽  
Phosphorous Slag ◽  
Better Than

The present study aims to investigate the opportunity to largely substitute low heat Portland cement of mass concrete with supplementary cementitious materials. The pozzolanic reaction of two types of supplementary cementitious materials, phosphorous slag powder and fly ash , were determined by X-ray diffraction, differential thermal analysis–thermogravimetry and scanning electron microscopy from 28 to 90 days. The properties of mortar and mass concrete containing 30% of supplementary cementitious materials were also investigated. Results showed that supplementary cementitious materials could decrease the amount of calcium hydroxide, fill the capillary pores, thus making the mortar and mass concrete more compact and durable. Long-term strength of mass concrete containing 30% of supplementary cementitious materials were comparable (or even better) than the control concrete (without supplementary cementitious materials) at constant workability, while the Young’s modulus was lower than the control concrete.

scholarly journals Development of Multi-Dimensional 3D Printed Vascular Networks for Self-Healing Materials

2017 ◽  
Author(s):  
Isabel P. S. Qamar ◽  
Richard S. Trask
Keyword(s):  
Fused Deposition Modeling ◽  
External Source ◽  
Additive Manufacture ◽  
Crack Plane ◽  
Self Healing ◽  
Vascular Networks ◽  
Free Standing ◽  
Damage Site ◽  
Fused Deposition ◽  
3D Printed

Self-healing materials have emerged as an alternative solution to the repair of damage in fibre-reinforced composites. Recent developments have largely focused on a vascular approach, due to the ability to transport healing agents over long distances and continually replenish from an external source. However fracture of the vascular network is required to enable the healing agents to infiltrate the crack plane, ceasing its primary function in transporting fluid and preventing the repair of any further damage events. Here we present a novel approach to vascular self-healing through the development and integration of 3D printed, porous, thermoplastic networks into a thermoset matrix. This concept exploits the inherently low surface chemistry of thermoplastic materials, which results in adhesive failure between the thermoplastic network and thermoset matrix on arrival of a propagating crack, thus exposing the radial pores of the network and allowing the healing agents to flow into the damage site. We investigate the potential of two additive manufacturing techniques, fused deposition modeling (FDM) and stereolithography, to fabricate free-standing, self-healing networks. Furthermore, we assess the interaction of a crack with branched network structures under static indentation in order to establish the feasibility of additive manufacture for multi-dimensional 3D printed self-healing networks.

scholarly journals Self-Healing Products of Cement Pastes with Supplementary Cementitious Materials, Calcium Sulfoaluminate and Crystalline Admixtures

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7201
Author(s):  
Byoungsun Park ◽  
Young-Cheol Choi
Keyword(s):  
Phase Composition ◽  
Cementitious Materials ◽  
The Self ◽  
Ion Concentration ◽  
Supplementary Cementitious Materials ◽  
Self Healing ◽  
Cement Pastes ◽  
Main Compound ◽  
Calcium Sulfoaluminate ◽  
Granulated Blast Furnace Slag

The phase composition of self-healing products generated in cracks affects self-healing performance. This study investigated the self-healing products of cementitious materials using supplementary cementitious materials (SCMs), a calcium sulfoaluminate (CSA) expansion agent, and crystalline additives (CAs). Ground-granulated blast-furnace slag (GGBFS), fly ash (FA), and silica fume (SF) were used as SCMs, and anhydrite, Na2SO4, Na2CO3, and MgCO3 were used as crystalline additives (CAs). An artificial crack method was used to collect the self-healing products in the crack of the paste. The phase composition of the self-healing products was analyzed through X-ray diffraction (XRD)/Rietveld refinements and thermogravimetry/differential thermogravimetry (TG/DTG) analysis, and their morphology and ion concentration were examined through scanning electron microscopy with energy dispersive spectroscopy (SEM–EDS). From the results, the main compound of self-healing products was found to be calcite. GGBFS and FA decreased the content of portlandite, and the use of CAs led to the formation of alkali sulfate and alkali carbonate. The SEM–EDS analysis results showed that when GGBFS and FA were used, a large proportion of the self-healing products contained C-S-H and C-A-H, and the use of CSA led to the formation of monosulfate and ettringite.

scholarly journals Textile Reinforced Concrete in Combination with Improved Self-Healing Ability Caused by Crystalline Admixture

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5787
Author(s):  
Hana Žáková ◽  
Jiří Pazderka ◽  
Pavel Reiterman
Keyword(s):  
Reinforced Concrete ◽  
Portland Cement ◽  
Concrete Structures ◽  
Cementitious Materials ◽  
Independent Study ◽  
The Other ◽  
Self Healing ◽  
Textile Reinforced Concrete ◽  
Secondary Hydration

The main aim of this study was to investigate the improved autogenous healing of concrete caused by a crystalline admixture in combination with textile reinforced concrete (TRC). This phenomenon (improved healing) has not yet been described by any independent study, and not at all in relation to TRC. The results of the study confirmed that the interaction between TRC and the crystalline admixture’s self-healing ability is advantageous and usable. The application of crystalline admixture could ensure the long-term entirety of the TCR element, where microcracks could occur. This allows for the creation of advantageous, thin (achieved by TRC) and waterproof (achieved by the crystalline admixtures) concrete structures. Moreover, this does not depend on temperature in the range of 4–30 °C (lower temperatures are of course problematic, as for most other cementitious materials). However, the interaction of both materials has its limits; the cracks must not be too wide (max. 0.1 mm), otherwise they will not heal. On the other hand, the advantage is that it does not matter what type of cement is used (CEM I and CEM II showed the same results), and the composition of the newly formed crystals in the cracks corresponds to the composition of the C-S-H gel, so it can be assumed that secondary hydration of the Portland cement occurred in the crack area.

Sign in / Sign up

Export Citation Format

Share Document