CAPLab2020 is intended to assist pavement designers by providing alternative geogrid,
geotextile, and pavement section thickness, based on data provided by the user.
CAPLab2020 uses referenced engineering standards, testing, and research that are intended to
provide a sufficient reinforced pavement depth to limit surface rutting to an acceptable level
over the design life of the pavement.
The suggested layouts generated by CAPLab2020 are intended as a guide only. You must use
appropriate judgement in applying the CAPLab results to your specific project, and the
CAPLab2020 results must be checked and approved by a suitably qualified pavement engineer before
construction.
CAPLab2020 is intended for use in the New Zealand environment only. CAPLab2020 must not be used
for projects located outside of New Zealand.
CAPLab2020 is for the sole use of the person who registered with Cirtex Industries Limited
(‘Cirtex’) and to whom CAPLab2020 was made available to by way of website login credentials.
Every user of CAPLab2020 must be registered with Cirtex. Use of CAPLab2020 by anyone who has not
registered with Cirtex is not authorised.
Design methodologies
The following is an overview of the design methodology used by CAPLab2020; for further
information and source data relating to the design methodologies, please contact Cirtex on 0800
247 839.
The NZTA released in 2017 a new publication called “New Zealand guide to pavement structural
Design”. This publication carried forward the recommendation from the previous NZTA supplement
to the AustRoads pavement design guidance as regards geosynthetic reinforcement as follows: –
“It is up to the geosynthetic supplier to provide relevant and credible evidence that such
savings are applicable for the particular product in question. The saving in pavement thickness
must not exceed the lesser of 150mm or one third of the pavement thickness irrespective of the
design process used. In addition, the reduced depth must be realised in the subbase layer and
not the basecourse layer”
The CAPLab2020 pavement design tool uses the AustRoads Fig 8.4 design formula as the basis of
the unstabilised section, then incorporates the specific benefit of the Tenax 3DT geogrids as a
layer coefficient ratio derived from full scale testing on the specific geogrid being used and
outputs a geosynthetic stabilised pavement thickness to compare with the unstabilised section.
Due to the impressive performance of the Tenax 3DT grids, in most cases this will show a greater
reduction than the 30% or 150mm allowed for in the NZTA guidance. Therefore, the CAPLab2020
pavement design tool will also give another option called the “NZTA Section” for a pavement that
is constrained to the maximum reduction suggested by NZTA. In this situation the pavement
section, which is deeper than the fully optimised section, will likely have substantial built in
resilience.
Disclaimer
CAPLab2020 is an information tool and is not a substitute for professional judgement or a formal
quotation for products supplied by Cirtex. Many project variables, including site and
construction conditions, will impact the final result of the project.
Cirtex offers this service in good faith and to provide information only. You must make your own
enquiries and seek independent advice from a suitably qualified pavement engineer and other
relevant industry professionals before relying or acting on any information made available to
you through CAPLab2020.
In using CAPLab2020, you take full responsibility for the accuracy, adequacy or completeness of
any information or data you enter, and Cirtex excludes all liability whatsoever arising from any
output which is derived by such use. Any pricing indications provided with CAPLab2020 are
indicative only, and using CAPLab2020 does not constitute an agreement for supply of goods by
Cirtex.
Cirtex will not be liable for any loss resulting from any action or reliance made by you on any
information or material made available to you through CAPLab2020.
To the maximum extent permitted by law, Cirtex and their associated persons do not warrant that
CAPLab2020 will meet your requirements and do not provide any warranties of any kind, including
fitness for a particular purpose or the price and savings with a project output, in respect of
either CAPLab2020 or any finished pavement surface.
Cirtex and their associated persons will not be liable whether in contract or tort or otherwise,
for any loss or damage of any kind arising directly or indirectly from your use of CAPLab2020.
Cirtex and their associated persons are not responsible for any consequence arising out of the
unauthorised use of CAPLab2020, including any loss or damage arising from that unauthorised use.
Pavement design methodologies and practices and relevant codes and regulations may change over
time. Cirtex is under no obligation to update or re-issue CAPLab2020 to reflect any such changes
or to inform you of any such changes.
By using Cirtex’s website you also agree to our Terms of Use, which are available on our website or on request.
Do you agree to the terms and conditions?
CAPLab2020
Version 1.0.2
Project Name: N/A
Client Name: N/A
Location: N/A
Pavement Design Inputs
Select a CBR value
Subgrade CBR
Enter your DESA value
DESA
Select aggregate size
D85 Sub-base Aggregate
Project Costings Inputs
Enter Cost/m2
Cost of Geogrid
Width in metres
Width of Pavement (m)
Length in metres
Length of Pavement (m)
Enter Cost/m3
Cost of Sub-base Material Delivered
Enter Cost/m3
Placement & Compaction Cost
Enter Cost/m3
Excavation & Disposal Cost
Press 'Enter' to recalculate.
Value must be within 1.0E+05 and 1.0E+08, please try
again.
Unreinforced section based on the AustRoads figure 8.4 chart
Austroads Fig 8.4
Pavement Layer
Base Course Layer
150mm
Sub-base Layer
150mm
Geotextile Layer
Subgrade Layer
Limiting the depth reduction to 150mm or 1/3 of the subbase depth as per NZTA
guidance, a pragmatic option with more built in resilience than fully optimised
NZTA Section
Pavement Layer
Base Course Layer
150mm
Sub-base Layer
150mm
2nd Geogrid Layer
Geogrid Layer
Geotextile Layer
Subgrade Layer
Based on the Austroads fig 8.4 section with the layer coefficient ratio for
Tenax 3D geogrid applied