Durable railway tie

Patent metadata

Field	Value
Publication number	US-2018016752-A1
Application number	US-201615550304-A
Country	US
Kind code	A1
Filing date	Feb 10, 2016
Priority date	Feb 11, 2015
Publication date	Jan 18, 2018
Grant date	—

Abstract

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).

First claim

What is claimed is:

1 . A railway tie comprising:
an elongated member being made of a non-prestressed, self-healing engineered cementitious composite material, said material having a mixture of:
cement in the range of 500-700 kg/m3,
fly ash in the range of 600-800 kg/m3;
silica fume in the range of 0-100 kg/m3;
sand in the range of 350-550 kg/m3;
water in the range of 300-400 kg/m3;
polymer fiber in the range of 1-3% by volume;
superplasticizer in the range of 5-30 kg/m3; and
viscosity modifying admixture in the range of 0-30 kg/m3,
resulting in performance characteristics of:
compressive strength greater than 50 mpa;
first cracking tensile strength greater than 3 mpa;
ultimate tensile strength greater than 5 mpa;
tensile strain capacity greater than 1%;
flexural strength greater than 15 mpa; and
crack widths less than 100 μm.

2 . The railway tie according to claim 1 wherein the elongated member comprises an elongated body and at least one rail seat portion, said at least one rail seat portion supporting a railway rail.

3 . The railway tie according to claim 2 wherein the at least one rail seat portion being made of a self-healing engineered cementitious composite material having a compressive strength that is different from the elongated body.

4 . The railway tie according to claim 3 wherein the at least one rail seat portion has a compressive strength greater than about 150 MPa.

5 . The railway tie according to claim 1 , further comprising:
fly ash cenospheres in the range of 0-300 kg/m3.

6 . The railway tie according to claim 1 , further comprising:
tire rubber in the range of 0-200 kg/m3.

7 . The railway tie according to claim 1 wherein the cement is a Type I or Type III.

8 . The railway tie according to claim 1 wherein the fly ash is a Class F or Class C.

9 . The railway tie according to claim 1 wherein the fly ash cenospheres reduce the density of the railway tie.

10 . The railway tie according to claim 1 wherein the elongated body is absent of internal reinforcement members.

Assignees

• Univ Michigan Regents

Inventors

• Li Victor C
• Herbert Emily

Classifications

• C04B18/146

  Silica fume · CPC title

• E01B3/32 Primary

  with armouring or reinforcement (hollow sleepers E01B3/30) · CPC title

• C04B2201/52

  High compression strength concretes, i.e. with a compression strength higher than about 55 N/mm2, e.g. reactive powder concrete [RPC] · CPC title

• C04B28/04

  Portland cements · CPC title

• C04B2103/44

  Thickening, gelling or viscosity increasing agents · CPC title