Diana Bajare

Riga Technical University | RTU · Institute of Materials and Structures

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...

The growing interest of using industrial waste as recycled raw materials for the production of new, innovative materials is associated with effective use of natural resources and circular (zero-waste) economy. The research object is waste stream materials coming from chemical and processing industries, such as aluminum scrap recycling waste, chamot...

The dihydrate phosphogypsum (PG) based binder workability kinetics were investigated regarding to water-binder ratio (W/B) and chemical admixtures added to the composition of PG paste. PG was dried at 60 °C and homog-enized to powder like particles with collision milling in disintegrator and calcium sulphate hemihydrate was obtained by heating PG a...

The construction industry (and buildings) is one of the largest energy consuming and CO 2 emitting sectors in the world. To counter this, more lightweight structures are being used and energy saving applications are being developed. Phase change materials (PCM) are materials that can be considered to tackle these new challenges. It has been proven...

The hemp-lime concrete as a self-bearing thermal insulation material has a low thermal conductivity and neutral CO2 emissions. However, the strength limitation of lime binder is an issue to use this material as a load-bearing material. Magnesium oxychloride binders are of considerably higher strength level and better bio-compatibility compared to t...

Over the past years, the installations of Shallow Geothermal Energy (SGE) systems are increasing throughout Europe, and it is indicating that a specific and detailed legal framework is necessary. Towards this direction, this paper consists of an overview of legislation issues on SGE at European level, based on concise reviews from fourteen countrie...

Dihydrate phosphogypsum (PG) from phosphate fertilizer production plant was considered as secondar