Multi-functional cementitious materials with ultra-high damage tolerance and self-sensing ability

Patent metadata

Field	Value
Publication number	US-11891335-B2
Application number	US-201916294299-A
Country	US
Kind code	B2
Filing date	Mar 6, 2019
Priority date	Dec 22, 2017
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

Cementitious materials having high damage tolerance and self-sensing ability are described herein. These materials may replace conventional concrete to serve as a major material component for infrastructure systems with greatly improved resistance to cracking, reinforcement corrosion, and other common deterioration mechanisms under service conditions, and prevents fracture failure under extreme events. These materials can also be used for the repair, retrofitting or rehabilitation of existing concrete structures or infrastructure systems. Furthermore, these materials may offer capacity for distributed and direct sensing of cracking, straining and deterioration with spatially continuous resolution wherever the material is located, without relying on installation of sensors. The present invention relates to multifunctional cementitious structural or infrastructure materials that integrate self-sensing with damage tolerance for improving safety, extending service life, and health monitoring of structures, components, and infrastructure systems.

First claim

What is claimed is:

1. A multi-functional cementitious material comprising:
a. water;
b. cement;
c. aggregates, wherein the aggregates are fine sand or ground quartz;
d. pozzolanic ingredients at a level of about 0-70% wt of the multi-functional cementitious material;
e. conductive nanoparticulates at a level of about 0.1-30% vol of the multi-functional cementitious material;
f. superplasticizer, or/and accelerator, or/and retarder, or/and viscosity modifying agent; and
g. discontinuous reinforcing fibers, wherein the discontinuous reinforcing fibers are polyvinyl alcohol (PVA) fibers, polyethylene fibers, polypropylene fibers, basalt fibers, or combinations thereof,
wherein the cement, aggregates, and pozzolanic materials are mixed to provide a uniform dry mixture,
wherein the water and superplasticizer, or/and accelerator, or/and retarder, or/and viscosity modifying agent are mixed with the dry mixture to form a cementitious paste having a rheology favorable for even dispersion of reinforcing fibers and conductive nanoparticulates,
wherein the conductive nanoparticulates and the reinforcing fibers are mixed with the cementitious paste to produce the multi-functional cementitious material;
wherein the multi-functional cementitious material has a tailored network of micro to nano-sized pores, aggregates/matrix interfaces, and fiber/matrix interfaces that exhibits a cracking behavior capable of dissipating energy through multiple microcracking with self-controlled microcrack widths of about 10 μm to 100 μm during strain-hardening stage such that the cementitious material is ductile and damage-tolerant, and
wherein the multi-scale structure and network of partially conductive, conductive, and non-conductive paths in the cementitious material also enable the material to behave as an electrical piezoresistive self-sensor under multi-frequency AC probing for measurement and monitoring of its mechanical and deterioration state.

2. A multi-functional cementitious material comprising:
a. water at a level of about 3-30% wt of the multi-functional cementitious material;
b. cement at a level of about 10-50% wt of the multi-functional cementitious material;
c. aggregates at a level of about 0-60% wt of the multi-functional cementitious material;
d. pozzolanic ingredients at a level of about 0-65% wt of the multi-functional cementitious material,
e. conductive nanoparticulates at a level of about 0.1-30% vol of the multi-functional cementitious material, wherein the conductive nanoparticulates have a particle size ranging from about 1 nm to 1 μm;
f. a plasticizer at a level of about 0.01-1% wt of the multi-functional cementitious material, wherein the plasticizer is a polycarboxylate-based concrete superplasticizer;
g. an accelerator, retarder, viscosity modifying agent, or combinations thereof, are added to adjust rheology and setting time; and
h. reinforcing fibers at a level of about 0.1-8% vol of the multi-functional cementitious material, wherein the reinforcing fibers are polyvinyl alcohol (PVA) fibers, polyethylene fibers, polypropylene fibers, basalt fibers, or combinations thereof and wherein the reinforcing fibers have a length ranging from about 1 mm to 100 mm, and a fiber diameter ranging from about 1 μm to 500 μm,
wherein the cement, aggregates, and pozzolanic materials are mixed to provide a uniform dry mixture,
wherein the water, plasticizer, and accelerator, retarder, or viscosity modifying agent, are mixed with the dry mixture to form a cementitious paste having a rheology favorable for even dispersion of reinforcing fibers and conductive nanoparticulates,
wherein the conductive nanoparticulates and the reinforcing fibers are mixed with the cementitious paste to produce the multi-functional cementitious material;
wherein the multi-functional cementitious material comprises a tailored network of micro- to nano-sized phases and interfaces that exhibits a straining and cracking behavior capable of dissipating energy through sequentially formed multiple microcracks with controlled crack widths of about 10 μm to 100 μm during strain-hardening stage such that the cementitious material is ductile and damage-tolerant, and
wherein the multi-scale structure and interfaces of the cementitious material enables electromechanical behaviour such that the cementitious material behaves as a self-sensing material to detect and quantify its own mechanically-, chemically-, or environmentally-induced strain, damage, or deterioration with spatially continuous resolution wherever the multi-functional cementitious material is located in a structure, through alternating current (AC) or direct current (DC) electrical probing.

3. The multi-functional cementitious material of claim 1 , wherein the mechanical state being measured and monitored is strain, displacement, damage, cracking, chloride penetration, or deterioration that are mechanically, chemically, or environmentally induced.

Assignees

• Univ California

Inventors

• Li Mo
• Li Xiaopeng

Classifications

• C04B28/04 Primary

  Portland cements · CPC title

• C04B14/022

  Carbon · CPC title

• C04B14/06

  Quartz; Sand · CPC title

• C04B16/0641

  Polyvinylalcohols; Polyvinylacetates · CPC title

• C04B18/08

  Flue dust {, i.e. fly ash} · CPC title