Development of solutions concerning regulation of proper deformations in alkali-activated cements
Journal Title: Восточно-Европейский журнал передовых технологий - Year 2019, Vol 5, Issue 6
Abstract
<p>The essence of the problem related to proper deformations in alkali-activated cements (AAC) complicated with high content of gel-like hydrate formations was analyzed. Cement types diametrically opposite in their compositions and, accordingly, in the content of gel phases during hydration, that is, the alkali-activated portland cement (AAPC) and alkali-activated slag cement (AASC) were taken for consideration. Approaches to formation of an effective structure of artificial stone counteracting shrinkage deformation by means of interference in structure formation when using complexes of mineral and organic compounds were proposed. Such compounds in composition of complex organo-mineral admixtures jointly influence intensification of crystallization processes and formation of an effective pore structure and morphology of hydrate phases while reducing water content in artificial stone. Salt electrolytes of various anionic types and anion-active surface-active substances were considered as ingredients of the proposed complex modifying admixtures.</p><p>It has been found that the "salt electrolyte–surfactant" system is the most effective for AAPC modification. It was shown that modification of AAPC with this complex admixture based on NaNO<sub>3</sub> reduced shrinkage from 0.406 to 0.017 mm/m. Instead, the use of Na<sub>2</sub>SO<sub>4</sub> provided AAC of this type with a capacity of expansion up to 0.062 mm/m. It was shown that the effect of compensated shrinkage of modified AAPC is associated with a higher crystallization of low-basicity hydrosilicates (CSH(B)) and calcium hydroaluminates (CaO∙Al<sub>2</sub>O<sub>3</sub>∙10H<sub>2</sub>O). An additional effect is associated with formation of sulfate-containing sodium-calcium hydroaluminate (for the Na<sub>2</sub>SO<sub>4</sub>-based system) and crystalline calcium hydronitroaluminate (for the NaNO<sub>3</sub>-based system) with a corresponding microstructure stress.</p>For further development, a complex admixture of "Portland cement clinker–salt electrolyte–surfactant" system was proposed for AASC modification. It provided shrinkage reduction from 0.984 mm/m to 0.683 mm/m. Minimization of the modified AASC shrinkage was explained by formation of sodium hydroalumosilicate of gmelinite type ((Na<sub>2</sub>Ca)∙Al<sub>2</sub>∙Si<sub>4</sub>∙O<sub>12</sub>∙6H<sub>2</sub>O) with a high degree of crystallization along with low-basicity calcium hydrosilicates. It was noted that the cement stone structure is characterized by high density, uniformity, and consolidation of hydrate formations
Authors and Affiliations
Pavlo Krivenko, Volodymyr Gots, Oleh Petropavlovskyi, Igor Rudenko, Oleksandr Konstantynovskyi, Artem Kovalchuk
Keywords
Related Articles
- EP ID EP668816
- DOI 10.15587/1729-4061.2019.181150
- Views 76
- Downloads 0
Detection of human respiration patterns using deep convolution neural networks
<p class="a"><span lang="EN-US">The method for realtime recognition of respiration types (patterns) of a patient to monitor his conditions and threats to his health, which is a special case of the problem of human activ...
Forming the structure of whipped desserts when introducing the food additive "Magnetofood" to their formulation
<p>The food additive "Magnetofood", in the form of a nanopowder with particles the size of (70‒80) nm, has been designed and proposed as an improver for the structure of whipped desserts. "Magnetofood" can both independe...
Studying the quality of drill pipes clamped in a wedge clamp
<p class="Default">Much attention has been recently paid to institutional measures aimed at improving quality of products related to petroleum machine building, in particular, the implementation of quality management sys...
The research of possibilities for fast calculation of median consensus rankings
<p>We investigated the possibility of fast computation of collective expert estimates of the median type. Despite the widespread use of the Kemeny-Snell and Cook-Seiford medians for calculating the collective expert esti...
Studying the physicochemical regularities in the color- and phase formation processes of clinker ceramic materials
<p>The paper reports results of a comprehensive study, aimed at developing formulation-technological parameters for obtaining volumetrically dyed clinker ceramic materials with a wide range of colors. A possibility has b...