GeoCorner

Otsikko: Feasibility of treated recycled materials in rammed earth construction

Tekijä: Otso Laurila

Valvoja: Prof. Sanandam Bordoloi

Ohjaaja(t): Prof. Leena Korkiala-Tanttu and DSc. Anoosheh Iravanian

Tiivistelmä:

Rammed earth is a construction method in which moist soil or similar granular material is compacted into moulds or formwork. Used since prehistorical times, it offers the potential to reduce the carbon footprint of certain structures that nowadays are constructed using concrete. Such structures include non-load bearing walls such as noise walls and partition walls, but also blocks that could be stacked to form partition walls or to support and stabilize slopes.

The use of recycled materials in the construction industry is advocated due to increasing regulations on CO2-emissions and preservation of exhaustive natural resources. In this thesis, low emission composites were developed for application in stabilized rammed earth construction. The emissions of the composites in this thesis are lowered by exploring the utility of local municipal wastes, namely crushed concrete aggregate, incineration slag and utilizing a low-cement binder. The first section involves a forensic study on an existing rammed earth structure located in Helsinki that has been exposed to Nordic conditions. Based on the forensic analysis on rammed earth composite samples, the strength and durability are recognized to be pitfalls in visible deterioration of the existing structures. To further improve the performance of crushed concrete aggregate and incineration slag, samples of binder-stabilized rammed earth were produced. Part of the samples were treated with a hydrophobizing agent to potentially eliminate the degradation caused by the expansion of absorbed water during freezing. The samples were tested to determine their uniaxial compressive strength, propensity to capillary suction and freeze-thaw durability. Calorimetric measurements were done study the hydration process present in stabilized rammed earth. The chemical compositions of the materials were defined using X-ray diffraction measurements.

Uniaxial compressive strength values between 2,03 – 20,06 MPa were reached. Freeze-thaw durability of the samples was observed to be good after a limited set of freezing-thawing cycles, especially in the hydrophobized samples. A significant decrease in the capillary water absorption was observed in the hydrophobized samples, hinting to a possibility of using treated hydrophobized materials as way of mitigating freeze-thaw damages in rammed earth structures.

Aihe: Classification of bitumen using chemical and rheological properties.

Tekijä: Osei Afram Owusu

Valvoja: Professor Nina Raitanen

Ohjaaja: Professor Augusto Cannone Falchetto

Rahoitus: Not funded.

Tiivistelmä:

Bitumen is characterized by its chemical and rheological properties. These properties play a role in determining the performance, durability, and behaviours of bituminous materials under varying environmental and load conditions. The classification of bitumen based on both chemical composition and rheological behaviour is essential for ensuring its suitability for specific applications.

This research aims to classify the different bitumen based on the rheological and chemical properties. Dynamic Shear Rheometer (DSR) and Fourier Transform Infrared Spectroscopy (FTIR) tests were performed on bitumen samples. Seventy-one bitumen samples were found to contain chemical compounds like carbonyls (C=O), sulfoxides (S=O), aliphatic hydrocarbons (), and aromatic C-H compounds, with their absorbances increasing with increasing bitumen grades. Susceptibility to oxidation decreased with increasing bitumen grades. Eighteen bitumen samples with the same IDs as some Fourier transform infrared spectroscopy (FTIR) samples were tested to determine their rheological properties. The sample data were combined to generate datasets for grades 35, 50,70, 100, 120 and 160. Master curves showed smooth curves depicting sample consistency and can visually evaluate the rheological behaviour of different binders. Black diagrams showed no breaks with more temperature plots nearing 0⁰. Cole-Cole curves extended wider along storage modulus axes than the loss modulus axes depicting more energy storage during tests. All DSR samples exhibited viscoelastic properties with samples showing slightly varying viscous properties with increasing bitumen grade using master curves, black-space diagrams and Cole-Cole plots. Principal component analysis (PCA) was used to determine the bitumen binder classification using DSR and FTIR parameters with the principal components (PCs) according to sample grades and sources. PCA of FTIR components generated a 51% cumulative variance between PC1 and PC2 and did not satisfy the required 80% cumulative variance between PC1 and PC2. PCA of DSR however generated a cumulative variance of 91.4% which satisfies the PC1 and PC2 variance requirement. Analysing the DSR parameters according to grades and sources revealed that the storage, complex and loss moduli correlated with PC1 while the phase angle correlated with PC2. FTIR components analysis in PCA according to grades and sources also revealed a correlation between the second aliphatic peak  and C=O and their positive influence on PC1. The first aliphatic hydrocarbon  also had a close correlation and a negative influence on PC1. The second aliphatic hydrocarbon peak  and S=O positively correlated with PC2. DSR and FTIR samples with the same IDs were analysed with PCA, it was revealed that the aliphatic hydrocarbons with the higher peaks () around wavelengths 2750 cm^-1 – 3000 cm^-1 and carbonyl peaks (C=O) correlated with the storage, complex, and loss modulus. The first aliphatic hydrocarbon peaks () around 1250 cm^-1 – 1500 cm^-1 and sulfoxide (S=O) correlated with phase angle. PCA can classify bitumen by source and by bitumen grade. Phase angle, S=O, C=O and aliphatic hydrocarbons were the major bitumen classification variables according to the grades of bitumen. However, classification according to sources of bitumen did not generate strong PCA results.

Aihe: Rating System for Finnish Roads

Tekijä:   Christy Mariam Benny

Valvoja: Nina Raitanen, Professor of Practice

Ohjaaja: Augusto Cannone Falchetto, Assistant Professor

Rahoitus: 

Tiivistelmä:

Road infrastructure plays a pivotal role in enhancing economic and social development by improving transportation efficiency and safety. However, increased construction activities also contribute to emissions, prompting the need for road rating systems. A road rating system is a tool used to evaluate and rate roads based on predefined criteria, which may include sustainability, environmental impact, safety, and performance. It helps authorities, planners, and stakeholders measure how well a road meets certain standards and objectives. Rating systems developed for specific countries often require tailoring when applied elsewhere. An extensive literature review revealed the absence of an established road rating system specifically tailored for Finland.

This thesis aims to develop a tailored road rating system for Finnish highways. The system integrates the unique conditions of Finland, such as the freeze-thaw cycle, rutting, use of studded tires, winter weather management, safety, wildlife protection, and water conservation. The proposed system evaluates highways across five main categories: environmental sustainability, road use and safety, infrastructure and maintenance, accessibility and public interaction, and operational efficiency and innovation. Each category is assessed using a point-based scoring system, ensuring a comprehensive evaluation while remaining adaptable to the road conditions of Finland. The developed road rating system was demonstrated through a pilot test on the Vt 12 Eteläinen Kehätie in Lahti. The road scored 91 out of 110, which indicates a well-designed, sustainable, and safe road, with only minor areas requiring improvements.

Results from the pilot test and stakeholder feedback highlighted the simplicity of the road rating system and its effectiveness in prompting sustainability, innovation, and safety. The developed rating system can be utilised to assess the ability of Finnish roads to meet environmental goals, functionality, safety standards, and maintenance needs, guiding infrastructure development and improvements. The current system is designed for use in the operational phase of highways. However, with minimal modifications, it could be applied to various phases of road projects, offering flexibility for future adjustments.