Subbase Modification

Our subbase stabilisation services enable faster, more cost effective delivery of new pavement construction and existing pavement rehabilitation.

Hiway Stabilizers has led the development of subbase stabilisation and aggregate modification processes in New Zealand.

Our expert team is responsible for numerous long-term road maintenance contracts around the country. The technology we use meets all local engineering specifications and is accepted by NZTA. Our in-house design and project management team also offers a range of complementary consultancy services.

Stabilizers Subbase


Stabilisation of aggregates for new pavements.

Remediation of failed pavements.

Area wide pavement treatments.

Use of locally-sourced marginal aggregates, previously not suitable for road construction.

Subbase Modification

Our subbase stabilisation solutions strengthen and improve the performance of marginal or aged aggregates, saving both resources
and cost.

Backdrop Stabilizers Subbase 2


Strengthens and improves performance of marginal aggregates.

More cost effective than using premium aggregates.

Aggregate can be placed much faster – up to 1km of two lane road can be stabilised or modified in a day by a single crew.

Prepared surface (prior to sealing) is more durable and requires less maintenance than a premium aggregate alternative.

Significantly reduces the need to cut out failed pavement material.

Final trimming and surface preparation requires less time and effort.

Significantly reduces the amount of imported material needed to rebuild the pavement.

Conserves aggregate resources.

Quick turn-around process minimises inconvenience to the public.

Subbase Stabilisation

Subbase stabilisation is the process of stabilising existing subbase layers or imported subbase materials to substantially improve performance.

As well as enabling re-use of existing materials, the performance improvements delivered by subbase stabilisation also reduce the volume of premium aggregates needed. Both benefits create significant cost savings and reduce road construction time.

Stabilizers Subbase Stabilisation
Subbase Stabilisation

Aggregate Modification

Aggregate modification is a proven pavement construction technique that delivers a long-term solution, with significant cost savings and environmental benefits. It can be used in both subbase and base-course applications.

Traditionally, New Zealand pavements have been constructed using premium quality, imported aggregates. High production costs, limited sources and transportation requirements make this an expensive construction material.

Aggregate modification allows aggregates of a marginal quality to be improved to a point where they exhibit structural and performance properties equal to, or better than, those of premium quality aggregates.

The process reduces the need for new aggregates, improves the strength of the existing pavement and can be implemented quickly to reduce inconvenience to motorists. The result is a balanced and structurally sound pavement, created with minimal effort and a much lower cost than traditional cut and granular reconstruction methods.

Aggregate Modification
Stabilizers Subbase strip


In the 1980s Hiway Stabilizers began developing a range of innovative new aggregate stabilisation binders to complement our aggregate modification service.

Our aim was to offer cheaper, more environmentally-friendly alternatives to conventional products on the market.

Today our binder range includes industry-leading brands such as KOBM Binder™, which is widely used and considered to be ideal for New Zealand conditions.

Design & Project Management Services

Hiway Stabilizers offers a range of design and project management consultancy services for subbase improvement.

Our specialist aggregate testing service determines which stabilising binder is best suited to, and most cost effective for, a client’s project and materials.

Our team can also undertake pavement design, incorporating modified aggregate layers. Modified layers can be modelled and evaluated technically until the desired performance results are achieved.

We use NZTA recommended CIRCLY Design Software and best practice design process. Having contributed to the development and revision of many of the industry specifications and standards, we have a comprehensive understanding of their utilisation and compliance.