The efficiency of polycarboxylic superplasticizers (derivatives of acrylic (SP-A and SP-B) or maleic (SP-C and SP-D) acids) after esterification with polyoxyethylene glycols (PEG) in cement pastes was analysed.The chemical structure of the superplasticizers was defined by gel permeation chromatography (GPC) and Fourier transformed infrared spectroscopy (FTIR). According to the experimental results the superplasticizers - derivatives of maleic acid – display greater molar mass and are built from backbone polymaleic chains and very long side polyoxyethylene chains.It is shown that acrylic superplasticizers display lower molar mass and are built from polyacrylic backbone chains and a higher number of shorter polyoxyethylene side chains. The efficiency o superplasticizers has been measured through their hydrophilicity, defined as the absorbance ratio of the ether band AET1110 (STRCH2–O–CH2ET) (referred to as the hydrophilic oxyethylene groups) to the ester band AES1730-40(STRC=OES) (referred to as the hydrophobic ester groups O=C–O–C) (with constant contents of aliphatic groups). A higher hydrophilicity of maleic superplasticizers, in comparison to acrylic, results from greater participation by the hydrophilic than the hydrophobic groups. It is shown that superplasticizers based on maleic anhydride derivatives (SP-C and SP-D) are more efficient than superplasticizers – acrylic acid derivatives (SP-A and SP-B)

The motivation for research to help address climate change is a continuous process of searching for eco-friendly materials in the building industry, which will allow minimizing the negative impact of this sector on the environment. The main objective of the paper is to assess the properties of a natural resource such as straw as an eco-friendly material in various variants for use in low-energy demand construction. The research results will fill the knowledge gap in the field of numerical analyses of the energy demand of straw material buildings based on the results of the conducted laboratory tests. A test of a heat transfer coefficient was conducted with different orientation of straw stalks. Then, samples were subject to a fire resistance test to determine material behavior at 1000 °C. During the fire resistance test, the clay-based plaster was ‘burnt out’, which hardened its structure, effectively preventing flames from reaching the insulation layers in the form of straw stalks. As a result of shrinkage (no plaster mesh), the plaster cracked and turned brick-red in color. The insulation layer of straw under the plaster was charred to a depth of 3.0 mm due to the high temperature. However, when the torch was turned off, no fire spread was observed in any layer of the sample. The 3D models of the buildings were created for different eco-friendly materials applied to make external walls. The results of numerical simulation allowed determining the amount of final energy needed to heat the designed building at the level of 26.38 (kWh/m²·year). Conclusions of the above-mentioned tests indicate very good thermal insulating properties determined using the lambda coefficient of 0.069 (W/m·K) and the possible application of straw bales as an alternative for conventional construction. Research has proven that it is possible to construct a building with low energy requirements using natural, easily available waste and completely biodegradable material.

Short-channel structures of triangular and sinusoidal channel cross-sectional shape were examined experimentally to find their heat (or mass) transfer and flow friction (flow resistance) characteristics. A particular emphasis was placed on influence of the channels length (referred to its hydraulic diameter) on transport and hydrodynamic characteristics. The transport and friction properties were correlated in terms of dimensionless channel length with satisfactory accuracy. The dimensionless channel length was proved to be a key factor that determines the transport and friction coefficients. Comparison with ceramic monolith has shown possibility of using the structures in automotive catalytic converters.