University of Michigan

Other

Saudi Arabian Oil Company

University of Pa.

Victor C Li

Shuxin Wang

Jun Zhang

Thibault Villette

Hwai-Chung Wu

Mohammed Al Mehthel

Oscar Salazar Vidal

He Zhu

Emily Herbert

Hyunjoon Kong

Hyun-Joon Kong

Devki Desai

Gregor D Fischer

Waleed Nasser

En-Hua Yang

Yun Yong Kim

Qian Zhang

Duo Zhang

Brian R Ellis

Daniel G Soltan

An engineered cementitious composite (ECC) has a tensile strain capacity ranging from 8.6 to 12.5% and includes a cement precursor, unprocessed desert sand, and polymer fibers. The polymer fibers may be ultra-high molecular weight polyethylene fibers, polypropylene fibers, or a combination thereof. A method of preparing an ECC structure includes providing a cementitious precursor mixture including a cement precursor and unprocessed desert sand, introducing water into the cementitious precursor mixture to form a cement slurry, and adding polymer fibers to the cement slurry. The polymer fibers may be ultra-high molecular weight polyethylene fibers, polypropylene fibers, or a combination thereof. Then, the method includes forming a structure with the cement slurry and curing the cement slurry.

High durability engineered cementitious composites with polymer fibers

Printable cementitious compositions for additive manufacturing are provided, that have a fresh state and a hardened state. In fresh state, the composition is flowable and extrudable in the additive manufacturing process. In the hardened state, the composition exhibits strain hardening. In one variation, the strain hardening is represented by a uniaxial tensile strength of ≥about 2.5 MPa, a tensile strain capacity of ≥about 1%, and a compressive strength at 100 hours of ≥about 20 MPa. In other variations, the composition includes Portland cement, a calcium aluminate cement, a fine aggregate, water, a high range water reducing agent (HRWRA), and a polymeric fiber, as well as one or more optional components selected from: fly ash, silica flour, microsilica, attapulgite nanoclay, and/or hydroxypropylmethyl cellulose (HPMC). Methods of additive manufacturing with such compositions are also provided.

Self-reinforced cementitious composite compositions for building-scale three dimensional (3D) printing

Methods of preparing engineered cementitious composite precursors include carbonating a fly ash comprising &#x3e;about 25% by weight of calcium oxide (CaO) and having a water content of &#x3e;about 12% to &#x3c;about 18% by weight of water by exposing the fly ash to a first gas stream comprising carbon dioxide to form a carbonated fly ash. A steel slag is also carbonated that comprises &#x3e;about 40% by weight of calcium oxide (CaO) and having a water content of &#x3e;about 12% to &#x3c;about 18% by weight of water by exposing the steel slag to a second gas stream comprising carbon dioxide to form a carbonated steel slag. The carbonated fly ash and the carbonated steel slag are suitable for use as engineered cementitious composite precursors in a bendable engineered cementitious composite composition that further comprises Portland cement, a polymeric fiber, and a superplasticizer.

Sequestering carbon dioxide into precursors of bendable engineered cementitious composites

A railway tie being constructed of an engineered cementitious composite (ECC) material having: (1) a minimum of 2% tensile ductility of ECC, (2) complete absence of alkali-silica reaction (ASR), (3) high fatigue resistance of ECC at least five times that of normal concrete, (4) self-healing ability of ECC requiring only water and air, and (5) customization of ECC for lower stiffness in the tie (60% that of normal concrete) and higher abrasion resistance in the seat (three times that of normal concrete).

Durable railway tie

A Thermally Adaptive Ductile Concrete (PCM-ECC) having a tensile ductility ceramic with 5 times the thermal resistance, 2 times the specific heat capacity, and 400 times the tensile strain capacity of regular concrete.

Thermally adaptive ductile concrete

A formulation of a spray applied fire-resistive engineered cementitious composite (SFR-ECC) which is made by addition of polymeric fibers, vermiculite, bonding agent and lightweight aggregates to cement and water. The SFR-ECC formulation is made in wet cement and can be spray-applied. The durable SFR-ECC exhibits thermal conductivities sufficient for fire resistance with increased tensile ductility and impact resistance.

Sprayable strain hardening brittle matrix composites with fire-resistance and high ductility

Rapid repair and retrofit of existing infrastructures demand durable high early strength materials that not only deliver sufficient strength within a few hours of placement but also significantly prolong the maintenance interval. The invention comprises a class of newly developed polyvinyl alcohol (PVA) fiber-reinforced high early strength engineered cementitious composites (ECC) materials featuring extraordinary ductility. The tailoring of preexisting flaw size distribution through non-matrix interactive crack initiators in the composite matrix results in high tensile ductility. The resulting high early strength ECC materials are capable of delivering a compressive strength of 21 MPa (3.0 ksi) within 4 hours after placement and retaining long-term tensile strain capacity above 2%.

High early strength engineered cementitious composites

Cementitious composites engineered for self-healing, combining self-controlled tight crack width and extreme tensile ductility. Self-healing takes place automatically at cracked locations without external intervention. In the exemplary embodiment, fiber-reinforced cementitious composites with self-controlled tight crack width less than 50 &#x3bc;m and tensile ductility more than 2% are prepared. Self-healing in terms of mechanical and transport properties recovery of pre-damaged (by pre-cracking) composite is revealed in a variety of environmental exposures, include wetting and drying cycles, water permeation, and chloride submersion.

Engineered self healing cementitious composites

Sprayable fiber reinforced hydraulically setting mortars exhibit strain hardening behavior, and comprise hydraulically setting cement, less than 4 weight percent matrix interactive fibers, a non-Newtonian additive, a superplasticizer, optionally a viscosity control agent, aggregate, and further additives. The ductile composites can be prepared by spraying in thicknesses higher than conventional sprayable mortars.

Sprayable, strain-hardening cementitious compositions

Purposeful addition of crack-initiating voids in the form of low tensile strength particulates, particulates having low matrix interaction, or gas bubbles formed by chemical reaction, in a size range of 0.5 mm to about 5 mm, and preferably of a size commensurate with or larger than naturally occurring crack-initiating gaseous voids, to fiber-reinforced strain hardening cementitious composites generates controlled and uniform cracking which increases strain hardening behavior in conventionally dense cementitious compositions.

Process for increasing the ductility of high performance fiber-reinforced brittle matrix composites, and composites produced thereby

Fiber reinforced lightweight concrete composites employ less than 4% by volume of reinforcing fibers in conjunction with small particulate lightweight aggregates or voids, and cure to composites which exhibit high tensile strain and strain hardening behavior. The composites are useful for numerous structures in civil engineering.

Lightweight strain hardening brittle matrix composites

Short fiber-reinforced engineering cementitious composites which are self-compacting, can be prepared by adding hydrophilic polymer fibers to a cement composition containing polymeric thickener and superplasticizer. The compositions are exceptionally ductile and exhibit many of the physical characteristics previously available only with hydrophobic high performance polyethylene fibers.

Self-compacting engineered cementitious composite

The present invention relates to a concrete construction that comprises a concrete slab and a ductile strip adjacent the slab. The ductile strip comprises an engineered cementitious composite of cementitious material and reinforcing fibers with the ductile strip being directly bonded to the slab. The present invention also relates to a method of making or repairing a concrete construction, the method comprises providing a ductile strip adjacent a concrete slab, wherein the ductile strip is made of an engineered cementitious composite comprising cementitious material and hydrophilic and/or hydrophobic reinforcing fibers. The present invention further relates to a roadbed or building floors suitable for vehicular traffic, the roadbed comprises a plurality of slabs and ductile strips comprising an engineered cementitious composite of cementitious material and reinforcing fibers.

Concrete constructions employing the use of a ductile strip

A collapse-resistant frame system ( ) for a bridge or building structure includes a plurality of mechanically-interconnected columns ( ) and beams ( ). At least the lowermost columns are formed of a material ( ) that exhibits quasi-elastic behavior in response to seismic excitation, while the beams of the frame system are formed of a material ( ) that exhibits elastic/plastic behavior, such that quasi-elastic flexure of the columns under seismic loading will cause plastic hinge formation in the beam ends ( ) to thereby dissipate the rotational energy without significant plastic hinge formation in the column bases. In a disclosed embodiment, the column material is an engineered cementitious composite (ECC) matrix ( ) reinforced with fiber-reinforced plastic (FRP) ( ) to thereby provide a relatively-high flexural strength member having a relatively-lower flexural stiffness and higher elastic deformation limit, while the beam material is an ECC matrix reinforced with mild steel rebar ( ) to thereby provide a relatively-lower flexural strength member featuring high energy-absorbing capacity.

Collapse-resistant frame system for structures

The present invention relates to processes for enhancing the bond strength of a cement matrix including reinforcement fibers and for modifying the surface characteristics of reinforcement fibers useful in cementitious materials. The processes further relate to controlling the interface properties and, more particularly, the bond strength (.tau.) and interface toughness (T.sub.i), between synthetic fibers and a cementitious material forming a matrix. By plasma treating synthetic fibers with an excitable gas capable of displacing hydrogen atoms occurring along said reinforcement fibers, the bond strength and interface toughness of the composite is dramatically increased over composites employing non-plasma treated fibers.

Growing community of inventors

Ann Arbor, MI, United States of America

Victor C Li