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Dextrins as Green and Biodegradable Modifiers of Physicochemical Properties of Cement Composites
Growing interest in the use of natural organic compounds in the production of green concrete with the use of plasticizers has been particularly noticeable in the literature of recent decades. Starch is an attractive material due to its abundance, the low cost of sourcing it, and its biodegradability, biocompatibility, and susceptibility to modification. The objective of the study was to evaluate the effect of starch hydrolysate additives on the physicochemical properties of cement composites and concrete. Compressive strength tests and cement slurry rheology measurements were carried out for water–cement ratios from 0.40 to 0.50 and for amounts of added dextrin from 0.0 to 0.7% in relation to the cement weight. The dextrins used were characterized in terms of their viscosity, polymerisation degree, and surface activity in air/water systems. Conducted research indicates that even the minimum content of dextrin increases the fluidization of cement mixes (the flow diameter increased by 67.5% compared with the mixture without the admixture), enables the reduction of mixing water, and contributes to the compressive strength of cement mortars. A further decrease in the w/c ratio to the value of 0.40 resulted in an increase in the strength value of up to 67.9 MPa, which provided a 40% increase in strength. The degree of the polymerisation of added dextrin is seen as having an effect on the physical parameters of the cement mortar; the shorter the polymer chain of the studied dextrin, the more packed the adsorbent layer, and the greater the flow diameter of the cement mortar.
The Study on Possible Applications of Lightweight Concrete Based on Waste Aggregate in Terms of Compressive Strength and Thermal Insulation Properties
Effect of Biodegradable Dextrin LU-1400-2 on Selected Properties of Cement Mortars
"This paper presents the results of a study on the effect of fully biodegradable modified starch in the form of LU-1400-2 dextrin(denoted d2) and two commercial plasticizers P1 and P2 on selected properties of cement mortars. The studied cement mortar wasenriched with 0.25%, 0.30%, 0.35%, and 0.40% d2 dextrin, relative to the weight of the cement. The tests carried out indicate that theaddition of dextrin to cement mortars results in an increase in strength (a 9% increase was observed with 0.25% dextrin) andliquefaction of the mixtures. However, commercial plasticizers were found to decrease compressive strength. Starch derivatives are atype of natural plasticizer that is more environmentally sustainable than other types. They are produced from renewable sources, suchas plants, and their production generates less waste and involves low greenhouse gas emissions. They are produced from renewablesources, such as plants, and their production generates less waste and involves low greenhouse gas emissions. Preliminary studiessuggest that dextrins have great potential as natural plasticizers. The increasing popularity of natural plasticizers in the chemical andconstruction industries is due to a growing interest in sustainability and concern about the harmful effects of traditional chemicalplasticizers."