Life cycle assessment of cost-optimized buttress earth-retaining walls: A parametric study

TLDR: In this paper, life cycle assessments are carried out on 30 optimized earth-retaining walls of various heights (4-13m) and involving different permissible soil stresses (0.2, 0.3 and 0.4 MPa) in Spain.

About: This article is published in Journal of Cleaner Production.The article was published on 2017-01-01 and is currently open access. It has received 52 citations till now. The article focuses on the topics: Formwork & Retaining wall.

Figures

Fig. 1. Earth-retaining wall designs 546

Fig. 11. Development of the POCPhigh with regard to wall height and permissible soil stress 569

Fig. 10. Development of the ODP with regard to wall height and permissible soil stress 567

Fig. 3. Dimensions of the earth-retaining wall 551

Fig. 12. Development of the POCPlow with regard to wall height and permissible soil stress 571

Fig. 13. Development of the contribution ratio of every element over the GWP according to 573 wall height. 574

Frequently asked questions

Q1. What are the contributions in this paper?

12 In this paper life cycle assessments are carried out on 30 optimized earth-retaining walls of 13 various heights ( 4–13 m ) and involving different permissible soil stresses ( 0. 2, 0. 3 and 0. 4 MPa ) 14 in Spain. Secondly, this paper evaluates the contribution range 17 of each element to each impact. Moreover, the influence of the wall height on the contribution 19 of each element over the total impact is studied. This paper then provides the impact factors per 20 unit of concrete, steel, and formwork. Findings indicate that concrete is the biggest contributor to all impact 23 categories, especially the global warming potential. 

Q2. how many distances are automatically implemented in the 256 respective LCA-process?

Remaining transportation 255 distances such as the movement of sand and gravel are automatically implemented in the 256 respective LCA-process created by Ecoinvent. 

Q3. What is the final product considered within the production 215 stage of the life cycle?

The final product considered within the production 215 stage of the life cycle is the manufacturing of the plywood used as formwork for casting the 216 concrete walls in-situ. 

Q4. What is the contribution of the formworks to the GWP?

An 313overall decreasing trend is also identified for the formworks contribution, which has most 314 impact on the ADP, POCPhigh and POCPlow of 4 m walls with percentages of 8.4%, 13% and 315 10.6%, respectively. 

Q5. What are the maintenance activities expected during the construction phase?

During this stage only maintenance activities are 228 expected; however, as sufficient durability constraints were imposed on the structures, 229 maintenance activities are not considered. 

Q6. What is the main reason why OpenLCA was used in a wide range of applications?

OpenLCA has been used in a wide range of 104 applications worldwide since its release in 2007, i.e., agricultural sector (Ingwersen, 2012); 105 distribution energy networks (Rodríguez et al., 2014) and power electronics (Braunwarth et al., 106 2015). 

Q7. How much of the impact ratio for the formwork decreases for all impacts?

327 The contribution ratio for the formwork decreases for all impacts, depending on the impact at 328 least to 0.81 for the EP and even down to 0.76 for the POCPhigh. 

Q8. What types of constructions would have less impact on the main flow contributors to such categories?

These types 170 obtained less impact on ADP, AP, GWP, POCP, as the main flow contributors to such 171 categories (cement and steel manufacturing) would be replaced by stone, with fewer burdens 172 of burning processes. 

Q9. What is the contribution ratio for the steel?

emissions for 342 POCPhigh and POCPlow for the steel, where it is the main contributor, are 4.68E-4 and 5.65E-4, 343 respectively.