IE970321A1

IE970321A1 - Conductive concrete

Info

Publication number: IE970321A1
Application number: IE970321A
Authority: IE
Inventors: Bailey Neil
Original assignee: Patricia Bailey
Priority date: 1996-05-10
Filing date: 1997-04-30
Publication date: 1997-12-03
Also published as: GB9609797D0

Abstract

An aggregate is disclosed for mixing with an emulsifier in order to form an electrically conductive concrete upon solidifying of the emulsifier. The aggregate comprises petroleum coke that is calcined at a high temperature for a period of time sufficient to ensure a content of no less than 98.1% by weight pure carbon, no more than 0.8% by weight of sulphur and no more than 0.1% by weight of sulphates.

Description

Conductive Concrete The present invention relates to an aggregate for producing electrically conductive concrete.

It has previously been proposed to render concrete electrically conductive by the addition of carbon. Electrically conductive concrete is desirable when it is desired to earth an electrical conductor. The electrically conductive concrete is poured into a hole, or matrix of trenches, dug in the ground and the electrode to be earthed is set within the concrete.

It has been found that the electrode being earthed through the electrically conductive concrete, which is commonly made of copper, tends to corrode by reacting over a period of time with the concrete and the aim of the present invention is to mitigate this disadvantage found with prior art compositions.

In accordance with the present invention, there is provided an aggregate for mixing with an emulsifier in order to form an electrically conductive concrete upon solidifying of the emulsifier, the aggregate comprising petroleum coke that is calcined at a high temperature for a period of time sufficient to ensure a content of no less than 98.1% by weight pure carbon, no more than 0.8% by weight of sulphur and no more than 0.1% by weight of sulphates.

The invention is predicated on the realisation that corrosion of the embedded electrode is the result of acidity in the concrete and the reduction in the sulphur and sulphate content result from calcining the petroleum coke in a kiln, ensures that the set concrete is chemically neutral, i.e. that it has a pH value of 7.

It is also preferred that any hydrocarbons and any other organic volatile matter in the aggregate should not exceed 0.2% by weight.

OPEN TO PUBLIC INSPECTION UNDER SECTION 2Q AND RULE & JNL No...../.£2.6......OF S(TFL1 F -2 The moisture content of the aggregate should preferably not exceed 0.2% by weight and any ash in the aggregate should not exceed 0.2% by weight.

The aggregate may be sold separately for mixing with any proprietary cement mixture, preferably in a ratio of between 2:1 and 3:1 by weight before water is added. It is however preferred to supply the aggregate in the form of a premix to which the user need only add water.

The premix may in this case consist of the petroleum coke aggregate and an emulsifier that may suitably include one or more materials selected from the group consisting of clinker, calcium silicate, aluminium oxide, ferrous oxide, magnesium oxide and calcium sulphate.

The optimum sieve mesh dimensions of the aggregate and the emulsifier and the consistency of the mix after the addition of water will vary with the application. If the concrete is to be set into a deep hole then a thin fine consistency is preferred whereas for pouring into shallow trenches a thicker coarser consistency is preferred.

The petroleum coke is preferably calcined by heating in a rotary kiln to a temperature that preferably lies within the range from 400°C to 900° C.

Claims

1. An aggregate for mixing with an emulsifier in order to form an electrically conductive concrete upon solidifying of the emulsifier, the aggregate comprising petroleum coke that is calcined at a high temperature for a period of time sufficient to ensure a content of no less than 98.1 % by weight pure carbon, no more than 0.8% by weight of sulphur and no more than 0.1% by weight of sulphates.

2. An aggregate as claimed in claim 1, wherein the quantity of any hydrocarbons or other organic volatile material present in the aggregate does not exceed 0.2% by weight.

3. An aggregate as claimed in claim 1 or 2, wherein the moisture content of the aggregate does not exceed 0.2% by weight.

4. An aggregate as claimed in any preceding claim, where the ash content of the aggregate does not exceed 0.2% by weight.

5. An aggregate as claimed in any preceding claim, wherein the petroleum coke is calcined by heating in a rotary kiln to a temperature within the range from 400°C to 900°C.

6. A premix for forming electrically conductive concrete comprising an aggregate as claimed in any preceding claim and an emulsifier.

7. A premix as claimed in claim 6, wherein the emulsifier one or more materials selected from the group consisting of clinker, calcium silicate, aluminium oxide, ferrous oxide, magnesium oxide and calcium sulphate.

8. A premix as claimed in claim 6 or 7, wherein the aggregate is premixed with the emulsifier in a ratio of between 2:1 and 3:1 by weight before water is added.