Assessment of the possibility of using lime rock as an aggregate for mortars modified with nanomaterials for repairs in historic buildings

MINIATURA 5

Funding Organization: National Science Centre

Project title: Assessment of the possibility of using lime rock as an aggregate for mortars modified with nanomaterials for repairs in historic buildings

Agreement number: DEC-2021/05/X/ST8/01674

Project implementation period: 16.12.2021 - 15.12.2022

Principal Investigator: dr Beata Iwona Klimek

Project value: 27 830,00 PLN

Funds granted for Lublin University of Technology: 27 830,00 PLN

Abstract: The scientific aim of the submitted project is to obtain new types of environmentally friendly mortars with aggregate stone - calcareous rock, modified with nanomaterials based on Ca (OH)2 particles for repairs in historic buildings. A scientific discipline in which the project i architecture and urban planning as the process and production engineering, is carried out, with an emphasis on technical and technological issues in architecture, urban planning and spatial planning The repair and renovation of a historic building requires an individual approach to the repaired object. The selection of repair materials should depend on the results of tests and laboratory analyzes. Repair mortars should have properties similar to those used during the erection of the facility. To evaluate the performance of lime rock waste mortars, an extensive experimental campaign was developed involving a series of tests characterizing the behavior of the designed mortars in terms of mechanical strength, water behavior, durability and other properties. The stages of the proposed project include: - production of new recycling aggregate obtained from demolition materials, - production of model mortars with the addition of new aggregate, and experimental selection of appropriate proportions and their modification with dispersions of Ca (OH)2 nanoparticles in alcohol; - study the impact and evaluation of the performance of mortars with limestone waste. The first stage of the project will include the production of a new aggregate and full characterization of its physical properties, including basic mechanical parameters, resistance to frost corrosion and water-soluble salts. The starting material for the research will be calcareous rock obtained from recycling. Lublin region is rich in historic and modern buildings made of rock. Some facilities are constantly repaired, others, due to their technical condition and intended use, are gradually deteriorating. A significant amount of the stone material is deposited in the landfills of post-demolition raw materials as non-biodegradable material.
The second stage of the project involves the design of compositions and the implementation of mortars with different proportions of sand replacement by recycled stone aggregate. It involves the examination of reference mortars with a different proportion of filler additions. Newly designed mortar mixtures will be analyzed by means of special tests in order to obtain an overall assessment of their performance as mortars. improving the properties and increasing the durability of the newly designed mortars, it was decided to use the Ca (OH)2 nanoparticle dispersion in alcohol as a modifier, especially as it turned out to be an effective product consolidating various works of art, in particular murals, stucco and building stones. Due to their colloidal nature (i.e. nanometric size) and depending on the alcohol used as a solvent, Ca (OH)2 molecules can penetrate a few millimeters in the material) where they react with atmospheric CO2 (i.e. carbonization process) to produce calcium carbonate (CaCO3). The precipitated product acts as a binder, giving the damaged material a more consistent texture. Moreover, compared to other consolidating compounds such as polymer resins, Ca (OH)2 nanodispersions show higher physicochemical properties and mechanical compatibility with the original materials, as well as better durability and reversibility. Mortar samples treated with the same type of dispersion at two different concentrations. The third stage of the project will include physical and mechanical tests of mortars and the assessment of the effectiveness and efficiency of the designed mortars using recycled aggregate with rocks, including the characteristics of the microstructure, as well as by assessing the antithesis properties of water vapor permeability and capillary water absorption.
The scope of research works planned in the project will allow to obtain new knowledge on the possibility of using calcareous rock as a substitute for natural sand. Lime rock is characterized by a high content of clay minerals. The use of trass or cement mortars has been problematic for many years due to different specificity and different properties of mortars and rocks. The use of lime rock instead of sand in mortars will allow for synergy of these two materials. in mortars, as a replacement for natural ones, also has the benefits of sustainable development. From an environmental point of view, the use of recycled fine aggregates has the following advantages: minimizes sand extraction, minimizes energy consumption and CO2 emissions, and prevents illegal deposits and landfilling of post-demolition materials.