US 5,902,068 A · Vehicle arresting unit fabrication methods

Abstract

Vehicle arresting blocks of cellular concrete are usable to safely slow travel of an object and may be used to construct an aircraft arresting bed at the end of an airport runway. For such purposes, cellular concrete blocks must be fabricated to exhibit compressive gradient strengths of predetermined values to provide sufficient, but not excessive, deceleration forces on an object. Material uniformity characteristics must be met to avoid unacceptable drag force variations, so that arresting blocks desirably exhibit a predetermined compressive gradient strength (e.g., a 60/80 CGS) over a depth of penetration of 10 to 66 percent of block thickness. A 60/80 CGS will typically represent an average compressive strength of 70 pounds per square inch over such depth of penetration. Prior applications of cellular concrete typically involved meeting minimum strength values and the production methods did not meet uniformity or compressive gradient strength predictability as required for arresting blocks. Described methods include parameter, ingredient and process controls and ranges effective to enable fabrication of arresting blocks having dry densities and compressive gradient strengths which can be specified in order to provide limited deceleration of aircraft and other objects. Limited deceleration can avoid destructive effects inherent in excess rates of deceleration. SEQUENCE LISTING (Not Applicable)

Claims33

Dependent claims

A method of forming a section of arresting material, characterized by a compressive gradient strength effective to provide limited deceleration of a moving object, comprising the steps of:

(a) forming a slurry of cement and water;
(b) permitting said slurry to undergo a hydration related temperature rise in a range of 5 to 12 degrees F., to reach a slurry temperature not exceeding 89 degrees F.;
(c) preparing a foam from water and a foaming agent;
(d) admixing said slurry and said foam to provide cellular concrete;
(e) placing a portion of said cellular concrete in a form representative of the shape of said section;
and
(f) curing said cellular concrete under controlled evaporative conditions to provide said section of arresting material in a self-supporting three-dimensional shape suitable to provide deceleration of a moving object.

4 more elements

Dependencies are inferred from the claim text.

Vehicle arresting unit fabrication methods

Life of this patent

Vehicle arresting unit fabrication methods

Life of this patent

Abstract

Claims33