The paper presents the results of research concerning the influence of micromaterials on the heat conductivity coefficient λ, specifically heat Cp and thermal diffusivity a of modified gypsum and geopolymer. Microspheres, hydroxyethyl methylcellulose (HEMC) polymer, and aerogel were used as the gypsum’s modifying materials. The study also investigated an alkali potassium-activated methakaolin-based geopolymer with the addition of aluminium dust. During the measurements of thermal parameters, the nonstationary method was chosen, and an Isomet device—which recorded the required physical quantities—was used. When compared to the reference sample, a decrease in the thermal conductivity and diffusivity of the hardened gypsum— and a simultaneous increase in specific heat—was observed with the addition of micromaterials. The geopolymer sample was characterized by the lowest value of thermal conductivity, equal to 0.1141 W/(m·K). It was over 62% lower than the reference sample containing only gypsum. The experimental values of the thermal conductivity of the gypsum samples with the addition of HEMC, aerogel and microspheres were, respectively, over 23%, 6%, and 8% lower than those of the unmodified gypsum samples. The lowest values of thermal conductivity were observed in the case of the gypsum samples modified with polymer; this resulted from the fact that the polymer caused the greatest change in the structure of the gypsum’s composite, which were expressed by the lowest density and highest porosity.

We can observe the growing tendency of usage of recycled concrete aggregate (RCA). Changes in waste materials management rules will result in necessity of more common reutilization of materials from demolished concrete structures. Thus new fields of RCA application and new ways of its utilization in concrete manufacturing are still being looked for.Research presented in the paper has been conducted to examine two methods of improving poor gradation of natural aggregate (NA) using RCA. The NA that did not fulfill requirements of gradation had been chosen. It consisted of ca. 75% of 2-4mm fraction. In the first method a part of NA was replaced with 2-16 fraction of RCA of low quality. In the second method also a part of NA was replaced this time with 4-8mm and 8-16mm fractions of good quality RCA. The amount of replacing fractions was precisely calculated in order to fit optimal gradation curve. Quality of the gradation was measured with so called gradation index. Mechanical properties of researched concretes was tested as well as some of their properties related to durability. It can be stated, on the basis of the results, that both methods improve most of the vital concrete properties

The paper presents an assessment of the impact of using additives on the strength of a binding material, i.e., building gypsum, and also the phase transformation that takes place in it. Microspheres, aerogel and polymer (HEMC) additives were added to a building gypsum slurry with a water to gypsum ratio of 0.75. In order to investigate their influence on bending strength, compressive strength, and the effect of high temperatures, differential scanning calorimetry (DSC), as well as tests of the multicomponent binder, were carried out in accordance with the applicable PN-EN 13279-2:2005 standard. The obtained test results allowed to determine that the used additives influenced the strength parameters of the obtained composites. It was shown that the applied additives decreased the compressive and bending strength of the modified gypsum. Despite these properties, the obtained gypsum materials are environmentally friendly because they reuse wastes, such as microspheres. Out of all the applied additives, the use of microspheres in an amount of 10% caused a decrease in the bending strength by only 10%, and an increase in the compressive strength by 4%.

The paper presents the results of research concerning the influence of a metallic micromaterial on the thermal conductivity λ, specific heat Cp, and thermal diffusivity a of modified geopolymers. Iron oxide in the form of powder with an average granulation of 10 μm was used as the geopolymer-modifying material. The research concerned geopolymer composite samples with metakaolin (activated with potassium silicate) and the addition of iron in amounts ranging from 0.5% to 2.5% in relation to the weight of the metakaolin. Additionally, the samples were modified with sand and fireclay in two different amounts—1:1 and 1:1.2 in relation to the metakaolin. The addition of fireclay caused a decrease in the thermal conductivity of the composites by 30% when compared to the samples with the addition of sand. The lowest value of the thermal conductivity coefficient λ was obtained for the geopolymer with metakaolin and fireclay. When the ratio of these components in the composite was 1:1, the value of thermal conductivity was equal to 0.6413 W/(m·K), while in the case of their ratio being 1:1.2, it was equal to 0.6456 W/(m·K). In the samples containing fireclay, no significant influence of the added iron on the values of thermal conductivity was noticed. In the case of the geopolymer with sand, the effect was noticeable, and it was most visible in the samples containing metakaolin and sand in the ratio of 1:1.2. It was noticed that with an increase in the addition of Fe, the thermal conductivity of the composite increased.

The procedure of designing the composition of concrete with the method of three equations demands to accept the assumptions regarding the consistence of concrete mixture. For the assumed consistency the water demand of aggregates and water demand of concrete is specified. In case of natural aggregates (NCA) the formulas, among others, of Sterne's of Bolomey's are used conditioning the water demand of aggregates from its granulation, kind and consistence of concrete mixture. There is lack of such dependencies in case of water demand of recycled aggregates (RCA). In such case there remains the empirical determination of the water demand, which in practice disqualifies the usefulness of the method of three equations to specify the concrete composition of on RCA aggregates. A way to solve this problem is looking for the relations between RCA water demand and its other qualities which are easy to specify in laboratory conditions in short time. The quality which gives such a chance to achieve this relation is the aggregates resistance to crushing whose measure is crushing indicator. This paper has made an attempt at specifying the manner of empirical definition of RCA water demand