Diana Bajare

• PhD
• Professor at Riga Technical University

This study investigates the effect of phase change materials (PCM) on the properties of modified potato starch binders and hemp shive-based bio-composites, emphasizing their potential for sustainable construction applications. PCM-modified binders have shown reduced viscosity during gelatinization, enhancing their workability and uniformity during...

This study investigates the fresh state and hardened state mechanical and durability properties of 3D-printed concrete. The mechanical tests focused on its anisotropic behavior in response to different load orientations. Compressive, flexural, and splitting tensile strengths were evaluated relative to the print layers orientation. Results showed th...

This study aims to define specific transferable engineering capabilities needed for the implementation (design and practices) of circular economy (CE) within a smart city setting. We conducted a critical literature review of over 100 studies on the core values of CE and smart cities to investigate the knowledge gap in this topic and understand what...

Globally, 1.5 billion annual tire outputs generate a substantial volume of end-of-life tires (ELTs), creating significant environmental challenges. Despite increased recovery rates, ELT management costs in Europe underscore the need for proactive strategies to mitigate environmental and health risks. This study comprehensively evaluates the environ...

The construction industry significantly impacts the environment through natural resource depletion and energy consumption, leading to environmental degradation. Circular Economy (CE) material efficiency strategies—such as material reuse, design for disassembly, prefabrication, and recycling—offer promising solutions for reducing resource consumptio...

The performance of high-performance concrete has been enhanced in the present study by incorporating non-metallic fibres without altering the binder content. The impact of these fibres on high-performance concrete flexural and compression characteristics and the arrangement of fibres within the composite were systematically analysed. Unlike convent...

This chapter presents a deep discussion of the recent case studies on implementation of best practices and strategies for the circular economy, and an integrated approach to CE management in the built environment. The case studies were evaluated by the following aspects: Design for Circular Economy; Resource Optimization; Collaborative Approaches;...

This section is devoted to analyzing the construction industry as one of the significant industries within the economy of any country with a high potential for circularity. According to Huovila and Westerholm [1], the buildings and construction sector is an essential contributor to environmental impacts and wealth creation in society, with social c...

Large infrastructure projects are significant for societal and economic development, involving different types of infrastructure and many stakeholders. This chapter outlines the stages of the project life cycle, emphasizing the importance of stakeholder engagement at all stages for successful project outcomes. The stages include initiation, plannin...

The building sector contributes around 39% of global carbon dioxide emissions and consumes nearly 40% of all the energy produced. Over the whole life cycle, the building sector yields over 35% of the EU's total waste generation. These facts substantiate the necessity to implement circular economy in the built environments, in order to mitigate glob...

The growing demand for sustainable building materials has boosted research on plant-based composite materials, including hemp shives bound with biodegradable binders. This study investigates the enhancement of potato-starch-based binders with sodium metasilicate and glycerol to produce eco-friendly bio-composites incorporating hemp shives. Potato s...

The utilization of waste generated from industrial production is a burden to overcome for society to reach a circular economy. Usually, production waste is associated with low-quality materials compared to its natural counterparts. In some cases, high-purity materials are generated, while different hazardous substances such as heavy metals, radioac...

This article presents the results of experimental measurements of the physical properties of new environmentally friendly bio-based composite building materials containing hemp shives bonded with a magnesium binder. Some of the tested materials contained an admixture of phase change material (PCM) of variable proportions in the binder to increase t...

A sophisticated characterisation of a porous material structure has been challenging in material science. Three-dimensional (3D) structure analysis allows the evaluation of a material’s homogeneity, pore size distribution and pore wall properties. Micro-computed tomography (micro-CT) offers a non-destructive test method for material evaluation. Thi...

Over the past decade, 3D printing with concrete has been widely adopted worldwide. The primary drivers for this innovation are the reduction in manual labor and the more efficient use of natural resources. New materials that are suitable for 3D printing are developed, which are characterized by rapid setting and robust physical and mechanical prope...

3D printing technology has the potential to reduce construction waste through its controlled manufacturing process and optimized material consumption, making it a promising sustainable construction approach with reduced environmental impact. However, current 3D printed structures often have a high carbon footprint due to the large amounts of fine-g...

To achieve optimal strength and printability, mortars used in 3D printing typically contain high proportions of cement and other fine-grained powders. Consequently, the majority of mixtures used in 3D printing have high carbon footprint. Hence, there arises a critical need to study alternative supplementary cementitious materials aimed at reducing...

Wood-cement particle boards are gaining popularity within construction materials as they combine natural fiber architectural value with Portland cement durability. The production of the material is associated with processing the produced fiberboards, which includes cutting, grinding, and polishing. The remaining wood-cement dust residues are classi...

The research explores pollution prevention strategies associated with end-of-life tyres (ELTs) through sustainable practices, focusing on repurposing ELTs into crumb rubber (CR) for use in composite concretes for civil engineering applications. Three disposal approaches are considered: recycling into crumb rubber for use in cement composites to enh...

The lightweight structures play a crucial role in mitigating the environmental impact of buildings throughout their lifespan. There is an interest in exploring various agricultural by-products as effective aggregates for filling framed timber structures. Natural fibers, such as hemp shives, are gaining attention for their environmental benefits, in...

Over the last decade, research has increasingly focused on reducing the use of natural resources and improving waste management in the construction industry. Various possibilities exist for reducing waste in this sector, ranging from using waste as filler materials to developing new binders and building materials. This study focuses on the developm...

Thermal insulation materials used in civil engineering have been developing throughout time. One of the latest thermal insulation used in construction sites with gained popularity is EPS aggregate and mineral binder-based composite. Waste recycling potential, low cost, and ease of installation have brought popularity to the material. This research...

Hempcrete is a promising self-bearing thermal insulation material, as it has low thermal conductivity and a minor to negative CO2 footprint. It is also believed to be applicable not only in building construction, but also for renovation or additional insulation, since hempcrete hygrothermal properties are compatible with wooden structural elements....

There is a growing interest in understanding and using local knowledge, resources, and stakeholders to achieve tailored and effective circular solutions in the built environment. Although the importance of clear centralised guidance and regulations are emphasised in the existing literature, there is also an emerging acknowledgement that understandi...

Phosphogypsum (PG) is the most significant solid waste in the world. However, only 15% of it is recycled, and the rest is stored in useless and environmentally-damaging stockpiles, which are continually growing. Therefore circular economy of PG through its utilisation in useful applications, is relevant and critical from an ecological perspective....

Additive manufacturing by 3D printing has emerged as a promising construction method offering numerous advantages, including reduced material usage and construction waste, faster build times, and optimized architectural forms. One area where 3D printing’s potential remains largely unexplored is in combination with lightweight materials, especially...

The construction and demolition waste recycling into secondary raw materials is vital to achieving a sustainable and circular building life cycle. Expanded polystyrene (EPS) is one of the materials whose recycling rate should be increased. EPS boards can be shredded and used as aggregate of lightweight cement composites resulting in a material with...

Plant-based fibre and cement binder material exhibited good thermal properties and low to moderate mechanical strength, making it a potential use as a self-bearing material and thermal insulator.

In the last decade, more research has been concentrated on reducing the usage of natural resources and waste management in construction building materials. There are many possibilities for reducing the waste from this sector, ranging from waste being used as filler materials to developing new binders and building materials. This research concentrat...

The objective of the research on rubberized concrete that substitutes sand fillers with rubber crumbs by volume or weight is to identify ways to utilize discarded rubber tires and improve the building industry’s sustainability. The research indicates that substituting sand fillers with rubber crumbs can have a substantial effect on the concrete’s p...

Bio-aggregate composites (BACs) are typically formed by binding plant origin aggregates using organic or inorganic binders. Composite boards are being manufactured from hemp shives and Portland cement or lime and such material is associated with the so-called “hempcrete”. To reach a low greenhouse gas emission rate, alternative binders must be cons...

Up to now, primary resources have been the main choice of raw material selection for production. Now, global market tendencies have brought significant attention to secondary resources as the price has been raised for primary materials, and there is a shortage of their delivery. This could bring an additional effort to increase the recycling level...

More than 4.4 billion metric tons of cement were produced in 2021 [1], making it one of the most common building materials. Unfortunately, excessive cement use brings up several environmental concerns, one being the enormous volumes of CO 2e (carbon dioxide equivalent) created as a by-product. CO 2e is a standard unit for measuring carbon footprint...

E nd-of- L ife cars and trucks T yres (ELT) are still an environmental issue around the world and in Latvia. The addition of rubber additives into concrete is quite well-studied worldwide. It is known that the introduction of rubber crumb in large quantities (> 5 % by volume) reduces the mechanical strength of the material and the modulus of elasti...

3DCP is becoming more common in the construction industry nowadays, however, the aspects of durability of printed concrete are not well-studied yet. This paper focuses on determining how frost-thaw cycles affect printed concrete samples, compared to cast samples of the same concrete mix and whether the conventional concrete frost resistance tests c...

Eco materials derived from natural plant fibres and mineral binders are an alternative solution for modern ecological construction. This research is devoted to developing production technology for ecological high-performance fibre composite materials based on hemp shives and magnesium binder. The proposed composite wall structures consist of outer...

Cement is a widely used building material, with more than 4.4 billion metric tons produced in 2021. Unfortunately, the excessive use of cement raises several environmental issues, one of which is the massive amounts of CO2e produced as a by-product. Using recycled materials in the concrete mix is widely employed to solve this problem. A method for...

The share of bio-based materials in modern construction needs to grow more rapidly due to increasingly stringent environmental requirements as a direct result of the climate emergency. This research aims to expand the use of hemp concrete in construction by replacing traditional lime binder with magnesium oxychloride cement, which provides a faster...

Three-dimensional concrete printing (3DCP) is becoming more common in the construction industry nowadays; however, the aspect of durability of printed concrete is not well-studied yet. Frost resistance is a very important factor for durability of concrete structures located in northern regions. Since air-entraining agents (AEAs) are widely used in...

Hempcrete is a bio-based self-bearing envelope and thermal insulation building material that is becoming more popular nowadays and has a low environmental impact, especially CO 2 emissions. This study looks for solutions for hempcrete printing using a custom-built gantry type 3D printer typically used for concrete 3D printing. Preliminary research...

The search for efficient waste source precursors for geopolymer production is active in scientific society. The feasibility of using calcined kaolin clay and fly ash as suitable precursors for the production of geopolymers is widely described and acknowledged. The availability and energy input required to produce such precursors hinders their compe...

Low energy building materials based on natural and renewable resources have become popular among customers. The natural occurrence of the raw materials and the idea to move closer to nature with its natural products have brought high interest in hempcrete. Hempcrete is a kind of binder-aggregate material where besides mineral binder, hemp shive agg...

The evolution of bio-based composites in the building industry is strongly linked with the growing demand for sustainable development, which is relevant nowadays. Hemp shives are a large group of organic residues that are obtained in the process of oil extraction as well as straw processing. These residues could be utilized along with a binder as c...

Thermal insulation bio-composites made of plant origin by-products as bio-aggregates are one of the ways to decrease the impact of the building and construction sector on CO2 emissions. In this study, three bio-aggregates were analysed for their potential use in the production of bio-composites with potato starch binder. Technologically important p...

Several methods have been proposed in the last years to evaluate the self-healing properties of concrete, and despite intense efforts towards standardization in RILEM committees and several research projects, no standards have been released yet. In the framework of COST Action SARCOS, an Interlaboratory Test (ILT) was organized to advance this topi...

The waste amount coming from construction and demolition (CDW) has significant volume and potential to provide the backbone of a secondary material bank. Up to now, little attention is paid to waste gypsum recycling from CDW while a shift in global attitude toward waste management brings motivation to use CDW gypsum as secondary raw material. The p...

Hempcrete is 3D printable, has sufficient buildability and strength to form an outer shell layer for self-supporting walls the inner layer of such walls can be filled with less dense hempcrete, providing adequate thermal resistance at an overall wall thickness of 400-640 mm.

According to European regulations, the construction industry supports and strives to save non-renewable natural resources, increases the share of reusable resources in production and attempts to use renewable natural resources as much as possible by creating alternative building materials, such as bio-composites. Various building materials containi...

Hempcrete is a very promising bio-based insulating material with a minor or even negative CO2 footprint and low thermal conductivity. To utilize it efficiently, it must be possible to make predictions regarding hempcrete hygrothermal performance and whether it is up to the modern standards—this requires a verified material model for use in numerica...

European regulations states that the construction industry must encourage the rational and prudent use of non-renewable natural resources, as well as and increase the use of reusable resources and promote the use of renewable natural resources in production. Bio-composites based on natural aggregates such as hemp shives are widely studied and used...

Hemp concrete is a well-known bio-based building material, but due to its relatively low compressive strength is mainly used as an insulation material with a load-bearing wooden frame. There are possibilities to expand hemp concrete application in construction by substituting traditional lime with magnesium cement. Magnesium oxychloride cement is a...

Carbon dioxide (CO2) emissions associated with Portland cement (PC) production is ranked as the highest among the construction materials and it is estimated that 8% of the worlds CO2 discharges is due to PC production. As an average, the production of PC clinker including calcination process generates 0.81 kg of carbon dioxide per one kg of cement....

The present research investigated bio-based construction material based on hemp shives and gypsum. Low-density material was developed with densities of 200, 300, and 400 kg/m³. Simple yet robust production technology was used. For the first time, a binder for biocomposites obtained from phosphogypsum was used and properties were compared to commerc...

This work is devoted to developing an energy-efficient solution for the external wall and evaluating its environmental impact. Several types of innovative single-layer and sandwich-type wall solutions were analysed and compared. Different constructive and thermal insulation materials were used, including traditional wall materials such as AAC (auto...

The paper presents a method of calculation of thermal conductivity of bio-based building composites by applying numerical approach which based on the real morphology of sample and the solution of heat conduction equation in the micro-scale. The real microstructure of composite sample was obtained from the X-ray micro tomography (microCT). Then the...

Short presentation with videos from our newly founded 3D printing laboratory and printing the first samples of hempcrete with lime binder

Development of manufacturing technology of novel building products with layered structure and made of ecological fibres high performance composites containing agricultural waste (hemp shives) with improved thermal properties by using microencapsulated phase change materials (PCM). Wall panel made of hemp shives ecological fibre composites. HEMP4NZE...

Self-healing concrete has the potential to optimise traditional design approaches; however, commercial uptake requires the ability to harmonize against standardized frameworks. Within EU SARCOS COST Action, different interlaboratory tests were executed on different self-healing techniques. This paper reports on the evaluation of the effectiveness o...

Amajor problem in the field of adsorbents is that binders (kaolin clay, bentonite) introduced to bind zeolites and ensure the needed mechanical strength, are not able to sorb gases like CO2 and N2, and decrease the overall adsorption capacity. To solve this problem, one of the pathways is to introduce a binder able to sorb such gases. Thus, in this...

Fluid catalytic cracking (FCC) catalysts, used in the petroleum industry, are sources of zeolitic by-products. These by-products are often used as sorbents for the removal of ammonium ions from wastewater. After a period of use, the zeolitic by-product loses its sorption properties and is no longer effective. The problem is the use of zeolitic by-p...

Biocomposite building materials with mineral binders are becoming more topical recently because they can address growing environmental concerns regarding carbon footprints and resource depletion better than traditional building materials. However, these new materials also pose new challenges. There have been issues with the compatibility of plant-o...

The construction industry is one of the largest emitters of CO 2 because the production of traditional building materials is highly energy-intensive and uses considerable amounts of raw materials. This research aims to decrease the negative environmental impact of the construction industry by providing biocomposites with a low environmental impact...

Due to the increase of water consumption, water treatment systems become more actual and innovative materials for water treatment are welcomed. Traditionally, alkalizing agents, such as lime or caustic soda, have been employed to increase the pH levels, which induce chemical clarification of wastewater. Some innovative ideas of using low-calcium, a...

This study aimed to determine the impact of the initial temperature of the paste (from 5 °C to 35 °C) and the addition of water, which reflects a decrease in the molarity of activation solutions (AS) by diluting 10 M NaOH with distillate water, on the rheological properties of geopolymer pastes. Additionally, this resulted in changes to the physica...

Alkali activated binders (AAB) are potential alternative to ordinary Portland cement. The AAB is produced by activating the source of amorphous SiO2 and Al2O3 with alkali solutions (NaOH, Na2SiO3·nH2O, KOH or etc.). As a result of alkali activation the N-A-S-H gel is forming as binding phase in the structure. Influence of different SiO2/Na2O ratio...

The potential of phosphogypsum (PG) as secondary raw material in construction industry is high if compared to other raw materials from the point of view of availability, total energy consumption, and CO2 emissions created during material processing. This work investigates a green hydraulic ternary system binder based on waste phosphogypsum (PG) for...

Development and commercialization of self-healing concrete is hampered due to a lack of standardized test methods. Six inter-laboratory testing programs are being executed by the EU COST action SARCOS, each focusing on test methods for a specific self-healing technique. This paper reports on the comparison of tests for mortar and concrete specimens...

Novel mycelium-based biocomposites (MBB) were obtained from local agricultural (hemp shives) and forestry (wood chips) by-products which were bounded together with natural growth of fungal mycelium. As a result, hemp mycocomposites (HMC) and wood mycocomposites (WMC) were manufactured. Mechanical, water absorption and biodegradation properties of M...

The concrete industry is eagerly pursuing the economic advantages of concrete and the improvement of its long-term properties. One of the most effective approaches to improve concrete properties is associated with replacing part of the Portland cement with pozzolanic additives. Although commercial pozzolans like silica fume have proven to be effect...

To decrease the environmental impact of the construction industry, energy-efficient insulation materials with low embodied production energy are needed. Lime-hemp concrete is traditionally recognized as such a material; however, the drawbacks of this type of material are associated with low strength gain, high initial moisture content, and limited...

Construction is one of the industries with the highest level of CO2 emissions, and it also has a negative effect on other environmental impact categories. This research aims to decrease the negative environmental impact of the construction industry by proposing alternative building materials that have lower environmental impacts due to their bio-ba...

Dolomite is the widespread sedimentary rock that finds a wide application in building industry and road engineering. During the treatment of dolomite rocks, a huge amount of fine fractions (0…8 mm) are produced and classified as by-products due to the limited range of applications. For example, nowadays more than 400 000–450 000 t dolomite by-produ...

This work reports and describes a novel alkali-activated metakaolin as a potential binder material for the granulation of zeolites, which are widely used as CO2 adsorbents. The alkali-activated binders are zeolite-like materials, resulting in good material compatibility with zeolite-based adsorbents. A major problem during the granulation of zeolit...

Building materials contribute a significant amount of CO 2 to overall greenhouse gas emissions and this environmental impact should be reduced to improve the sustainability of the construction industry. Although new and low-carbon materials are emerging, the majority of materials used are still traditionally produced and are highly carbon intensive...

Technological, physical and mechanical properties of mineral binders are often defined by the amount of water add to the binder known as W/B ratio. The role of water is contributed to the workability of fresh paste, hydration processes, porosity, mechanical performance and durability of the material. Present research summarizes the relationship bet...

A typical phenomenon in concrete structures is crack formation. Shrinkage cracks may appear in early stage of concrete. In late age cracks may appear due to process of serviceability and external weather conditions. Larger cracks interfere structural integrity, micro-cracks may result in durability problems as increase of water absorption, which re...

The experimental study is devoted to investigation on foamed concrete produced applying innovative intensive mixing technology by using a planetary ball mill. Modern type of foamed concrete represents cementitious composite material group which may be competitive with traditionally used autoclaved aerated concrete. Innovative mixing method makes po...

Global warming being increasingly discussed, solutions for reducing emission greenhouse gases become more important in all industry sectors. The total energy consumed in the construction sector contribute up to 1/3 from all greenhouse gases emissions. Large part of it comes from the cement production – 5 % of the total global emissions. The foam co...

Bio-based building materials (3BMs) are one of the solutions for how the construction industry can mitigate its negative environmental impact because of energy consumed in material production and due to the insufficient thermal insulation of buildings, as, in general, these materials sequester CO2 in them and have low thermal conductivity. One of t...

In this study, and for the first time, the possibility of using bulk type waste-based granulated alkali-activated materials (AAM) for inducing heavy metals extraction by precipitation and adsorption was evaluated. Waste metakaolin and aluminium scrap recycling waste proved to be suitable precursors to create AAM. Results indicate that both methods...