Desert Sand as the potential resource for the future

Project reference number: SEBE_SELF_AK_2

Self-funded research applications are invited for the following PhD project at Glasgow Caledonian University. Please note that as this project is not funded by a university studentship, the successful candidate will be required to source external funding for the research degree fees and living expenses while studying at the university.

Research discipline areas

Desert sand, granulometry, chemical composition, CO2 emission reduction, eco-cements, supplementary cementitious materials, Superabsorbent Polymers, microstructure

Research Themes

 Building Resilience and Environmental Impact


Research Project Summary

The construction industry growing demand for raw sand and cement has led to a shortage of sand resources in the past years. The production of concrete and mortars requires up to 80% of aggregate, including sand. So far, the concrete and reinforced concrete industry has refrained from using desert sand. The reasons for this are the rounded form of the particle, its grading and its chemical composition.

Desert sand has a narrow grain size distribution. That means that there are only minor deviations among the diameter dimension of most desert sand grains. The diameter of a desert sand grain is rarely larger than 5 mm.

In contrast to sand from the coast or a river bank, sand grains from deserts are moved upon one another by the wind. Hence, their surfaces erode evenly, resulting in a typical round form. In comparison to poorly graded grains, such round sand grains cannot be wedged or supported by one another, and there is the risk of sedimentation. The geometry of sand grain is one of two essential parameters determining the suitability of sand as a construction material.

In addition to the geometric characteristics, the chemical composition of the aggregate is also relevant. Depending on a source of sand different components like silt, clay, as well as various salts or sulphur compounds may be present. The presence of such elements, or its compounds, can have a negative influence on the hardening of concrete, or it can lead to damaging reactions in hardened concrete at a later time. Usually, damages are caused by expansive reactions. The best-known expansive reaction is called the alkali-silica reaction (ASR). The ASR manifests itself through the formation of netted cracks, efflorescence and local spalling of concrete. Frequently, further reactions occur in connection with sulphur compounds and expanded crystalline structures are formed.

The overall aim of this project is to evaluate suitability of desert sand for concrete production and to develop new technical methods, which would make it usable on the large scale. In order to achieve this goal the following objectives need to be addressed:

  • To analyse granulometry of sands from different sources and establish characteristic profiles
  • To determine chemical compositions of sands with special focus on sulphur compounds (SEM & EDX methods)
  • To perform feasibility studies for different types of concrete (theoretically)
    • To verify suitability by performing experimental investigations:
    • Properties of fresh mortars (rheology, setting times, air content)
    • Physical properties of hardened mortars (total water absorption, thermal conductivity)
    • Mechanical properties (compressive and flexural strength, modulus of elasticity)
    • Microstructural analysis (SEM and MIP methods)
  • To evaluate the performance of developed materials – durability assessment

 

Application deadline

The application deadline for February 2019 start, is 1st of December, 2018

Research supervisors

Candidates are encouraged to contact the following researchers for further details:

Modes of study

This project is available as a:

  • PhD: 3 years full-time or 4.5 years part-time.

Eligibility

Applicants will normally hold a UK honours degree 2:1 (or equivalent); or a Masters degree in a subject relevant to the research project. Equivalent professional qualifications and any appropriate research experience may be considered. A minimum English language level of IELTS score of 6.5 (or equivalent) with no element below 6.0 is required. Some research disciplines may require higher levels.

 

Specific requirements of the project

The project is particularly suited to students from civil and materials engineering background with good experimental and statistical skills, however, applications are also welcome from students from related disciplines such as chemistry and architecture. The successful candidate will need to demonstrate a good understanding of the technical aspects of the problem, any prior experience in the conservation sector would be an advantage.