In today’s market, it is imperative to be knowledgeable and have an edge over the competition. ACI members have it…they are engaged, informed, and stay up to date by taking advantage of benefits that ACI membership provides them.
Read more about membership
Become an ACI Member
Founded in 1904 and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design, construction, and materials, who share a commitment to pursuing the best use of concrete.
American Concrete Institute
38800 Country Club Dr.
Farmington Hills, MI
Chat with Us Online Now
Feedback via Email
Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Title: Unshrinkable Fill for Utility Cut Restorations
Author(s): J. Emery and T Johnston
Publication: Special Publication
Appears on pages(s): 187-212
Keywords: aggregates; backfilling; compacting; costs; impact;
pavements; performance; repairs; specifications; strength
Abstract:Utility cut restoration problems (settlements, voids, cracks and protracted maintenance) have a significant negative impact on pavement serviceability. A recent Metropolitan Toronto study quantified this impact and identified unshrinkable fill (very weak concrete) as the preferred solution. In addition to repair costs, road user costs and nuisance effects, substandard utility cut restorations increase the Metro maintenance surfacing costs by some $3 million annually. Pavement impairment was found to be a function of the large number of utility cuts (about 4000 per year) and significant non-compliance with specifications covering granu-lar backfill quality and compaction. While tighter granular spe-cifications enforcement was considered, the characteristics of controlled density backfill were assessed to provide a materials approach to improved restorations. The desired controlled density backfill characteristics were: reasonable cost; flowability; pavement structural support; excavatability; wide availability; standard materials without need for inspection; satisfactory long-term performance; and demonstrated use. Based on long-term Winnipeg experience and utility comments, unshrinkable fill (25 kg cement per m3, conventional concrete aggregates, 160 to 200 mm slump, usually air entrained, maximum 28 days strength of 0.4 MPa) was subjected to extensive field trials and cost analyses. It was found that unshrinkable backfill meets the technical requirements and is generally cost effective compared to properly compacted and inspected granular backfill. Unshrinkable fill from qualified suppliers is now required for all Metro utility cut restorations.
Click here to become an online Journal subscriber