Materiales de Construcción, Vol 67, No 328 (2017)

Eco-trench: a novel trench solution based on reusing excavated material and a finishing layer of expansive concrete

A. Blanco
Dept. of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Spain

P. Pujadas
Dept. of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Spain

C. Fernández
Dept. of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Spain

S. H.P. Cavalaro
Dept. of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Spain

A. Aguado
Dept. of Civil and Environmental Engineering, Universitat Politècnica de Catalunya, Spain


Installing utility pipelines generates a significant amount of trench arisings, which are usually transported to landfills instead of being reused as backfill material. This practice generates CO2 emissions and wastes raw materials. This paper presents a more sustainable solution, an eco-trench, which is based on re-using trench arisings as backfill and adding a top layer of expansive concrete to improve the eco-trench’s structural performance. The technical feasibility of the eco-trench was evaluated through a finite element model, which identified the degree of expansion in concrete required to avoid failure or subside the stresses caused by traffic. The potential expansion of concrete was measured under confined conditions in the laboratory by means of a novel test developed for this purpose. The results showed that adding calcium oxide generates the required internal stress. The results were then confirmed in a pilot experience.


Concrete; Mixture proportion; Expansion; Finite element method; Shrinkage

Full Text:



Etxebarria, M.; Ainchil, J.; Pérez, M.E.; González, A. (2013). Use of recycled fine aggregates for Control Low Strength Materials (CLSMs) production. Constr. Build. Mater. 44, 142–148.

Blanco, A.; Pujadas, P.; Cavalaro, S.H.P.; Aguado, A. (2014). Methodology for the design of controlled lowstrength materials. Application to the backfill of narrow trenches, Constr. Build. Mater. 72, 23–30.

Pujadas, P.; Blanco, A.; Cavalaro, S.; Aguado, A. (2015). Performance-Based Procedure for the Definition of Controlled Low-Strength Mixtures. J. Mater. Civil Eng.

Petit-Boix, A.; Roigé, N.; de la Fuente, A.; Pujadas, P.; Gabarrell, X.; Rieradevall, J.; Josa, A. (2016). Integrated Structural Analysis and Life Cycle Assessment of Equivalent Trench-Pipe Systems for Sewerage. Water Resour. Manag. 30 [3], 1117–1130.

WRAP (Waste & Resources Action Program). (2005). Identifying opportunities for recycling of excavated spoil from utility works within local authority areas, and promoting the use of recycled materials through good practice in procurement. Banbury, U.K.

WRAP (Waste & Resources Action Program). (2007). Recycled and stabilised materials in trench reinstatement, WAS005-002: Final Report, Banbury, U.K.

Chatterji, S. (1995). Mechanism of expansion of concrete due to the presence of dead-burnt CaO and MgO. Cem. Concr. Res. 25, 51–56.

Min, D.; Dongwen, H.; Xianghui, L.; Mingshu, T. (1995). Mechanism of expansion in hardened cement pastes with hard-burnt free lime. Cem. Concr. Res. 25 [2], 440–448.

Maltese, C.; Pistolesi, C.; Lolli, A.; Bravo, A.; Cerulli, T.; Salvioni, D. (2005). Combined effect of expansive and shrinkage reducing admixtures to obtain stable and durable mortars. Cem. Concr. Res. 35[12], 2244–2251.

Carballosa, P.; Calvo, J.L.G.; Revuelta, D.; Sanchez, J.J.; Gutierrez, JP. (2015). Influence of cement and expansive additive types in the performance of self-stressing and self-compacting concretes for structural elements. Constr. Build. Mater. 93, 223–229.

Pade, C.; Guimaraes, M. (2007). The CO2 uptake of concrete in a 100-year perspective. Cem. Concr. Res. 37 [9], 1348– 1356.

Yang, K-H.; Seo, E-A.; Tae, S-H. (2014). Carbonation and CO2 uptake of concrete. Environmental Impact Assessment Review. 46, 43–52.

TNO Diana BV. (2008). Diana User´s Manual, (http://www.

Ecole d'Avignon. (2005). Techniques et pratique de la chaux. Eyrolles, Ed. 2nd edition, Paris, France. PMid:16192769

ASTM (American Society for Testing and Materials). (1995). C806-95 Standard Test Method for Restrained Expansion of Expansive Cement Mortar 1, West Conshohocken, PA.

ASTM (American Society for Testing and Materials). (2009). C878/C878M-09 Standard Test Method for Restrained Expansion of Shrinkage-Compensating Concrete, West Conshohocken, PA.

Formosa, J. (2012). Formulaciones de nuevos morteros y cementos especiales basadas en subproductos de magnesio. Doctoral Thesis, Universitat de Barcelona, Barcelona, (in Spanish).

AENOR (Spanish Association for Standardization and Certification). (2005). UNE-EN 196-1:2005. Methods of testing cement - Part 1: Determination of strength, Madrid, Spain.

CEN (European Committee for Standardization). (2009). EN12390-3:2009. Part 3: Compressive strength of test specimens, Brussels, Belgium.

Copyright (c) 2017 Consejo Superior de Investigaciones Científicas (CSIC)

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.

Contact us

Technical support