Mechanical strengths, drying shrinkage and pore structure of cement mortars with hydroxyethyl methyl cellulose

2022 ◽  
Vol 314 ◽  
pp. 125683
Author(s):  
Shunxiang Wang ◽  
Zhaojia Wang ◽  
Tianyong Huang ◽  
Peiming Wang ◽  
Guofang Zhang
Keyword(s):  
Pore Structure ◽  
Methyl Cellulose ◽  
Drying Shrinkage ◽  
Cement Mortars ◽  
Mechanical Strengths

scholarly journals Properties of Calcium Sulfoaluminate Cement Mortar Modified by Hydroxyethyl Methyl Celluloses with Different Degrees of Substitution

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2136
Author(s):  
Shaokang Zhang ◽  
Ru Wang ◽  
Linglin Xu ◽  
Andreas Hecker ◽  
Horst-Michael Ludwig ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Bond Strength ◽  
Cement Mortar ◽  
Retention Rate ◽  
Methyl Cellulose ◽  
Tensile Bond Strength ◽  
Calcium Sulfoaluminate Cement ◽  
Calcium Sulfoaluminate ◽  
Cement Mortars

This paper studies the influence of hydroxyethyl methyl cellulose (HEMC) on the properties of calcium sulfoaluminate (CSA) cement mortar. In order to explore the applicability of different HEMCs in CSA cement mortars, HEMCs with higher and lower molar substitution (MS)/degree of substitution (DS) and polyacrylamide (PAAm) modification were used. At the same time, two kinds of CSA cements with different contents of ye’elimite were selected. Properties of cement mortar in fresh and hardened states were investigated, including the fluidity, consistency and water-retention rate of fresh mortar and the compressive strength, flexural strength, tensile bond strength and dry shrinkage rate of hardened mortar. The porosity and pore size distribution were also analyzed by mercury intrusion porosimetry (MIP). Results show that HEMCs improve the fresh state properties and tensile bond strength of both types of CSA cement mortars. However, the compressive strength of CSA cement mortars is greatly decreased by the addition of HEMCs, and the flexural strength is decreased slightly. The MIP measurement shows that HEMCs increase the amount of micron-level pores and the porosity. The HEMCs with different MS/DS have different effects on the improvement of tensile bond strength in different CSA cement mortars. PAAm modification can improve the tensile bond strength of HEMC-modified CSA cement mortar.

scholarly journals Effect of CaSO4 Incorporation on Pore Structure and Drying Shrinkage of Alkali-Activated Binders

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1673 ◽  
Author(s):  
Hyeongmin Son ◽  
Sol Moi Park ◽  
Joon Ho Seo ◽  
Haeng Ki Lee
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Drying Shrinkage ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
Activated Slag ◽  
Capillary Tension ◽  
Alkali Activated Binders ◽  
Internal Pore Structure ◽  
Alkali Activated

This present study investigates the effects of CaSO4 incorporation on the pore structure and drying shrinkage of alkali-activated slag and fly ash. The slag and fly ash were activated at a 5:5 ratio by weighing with a sodium silicate. Thereafter, 0%, 5%, 10%, and 15% of CaSO4 were incorporated to investigate the changes in phase formation and internal pore structure. X-Ray Diffraction (XRD), thermogravimetry (TG)/derivative thermogravimetry (DTG), mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), and drying shrinkage tests were carried out to find the correlation between the pore structure and drying shrinkage of the specimens. The results showed that CaSO4 incorporation increased the formation of thenardite, and these phase changes affected the pore structure of the activated fly ash and slag. The increase in the CaSO4 content increased the pore distribution in the mesopore. As a result, the capillary tension and drying shrinkage decreased.

scholarly journals The effect of nano silica on short term drying shrinkage of POFA cement mortars

2015 ◽  
Vol 95 ◽  
pp. 636-646 ◽  
Author(s):  
Nima Farzadnia ◽  
Hossein Noorvand ◽  
Abdirahman Mohamed Yasin ◽  
Farah Nora A. Aziz
Keyword(s):  
Drying Shrinkage ◽  
Nano Silica ◽  
Short Term ◽  
Cement Mortars

scholarly journals The influence of type of cement on the degradation of microstructure and transport properties of cement mortars exposed to frost induced damage

2018 ◽  
Vol 174 ◽  
pp. 01014
Author(s):  
Alicja Wieczorek ◽  
Marcin Koniorczyk
Keyword(s):  
Absorption Coefficient ◽  
Pore Structure ◽  
Water Absorption ◽  
Transport Properties ◽  
Cement Mortar ◽  
Gas Permeability ◽  
Water Absorption Coefficient ◽  
Freeze Thaw ◽  
Cement Mortars ◽  
Small Pore

The purpose of the study is to understand how the cyclic water freezing (0, 25, 50, 75, 100 and 150 freeze-thaw cycles) impacts microstructure and transport properties of cement-based materials. Tests were conducted on cement mortars with different water/cement ratios (w/c=0.45 and 0.40) and on two types of cement (CEM I and CEM III) without air-entraining admixtures. The changes of pore size distribution and open porosity were investigated by means of mercury intrusion porosimetry. Additionally, the relationship between intrinsic permeability and the water absorption coefficient of cement mortar samples was analysed. The water absorption coefficient and gas permeability were determined using capillary absorption test and the modified RILEMCembureau method. The evolution of transport coefficients with growing number of freeze-thaw cycles were determined on the same sample. It was also established that change of pore structure (a decrease of small pore volume <100nm and increase of larger pores >100nm) induces an increase of water transport parameters such as permeability and water absorption coefficient. The higher gas permeability corresponds to the higher internal damage. In particular, it is associated with the change of cement mortar microstructure, which indicates damage of narrow channels in the pore structure of cement mortars.

Experimental Research on Pore Structure of RCA and its Impact on Drying Shrinkage

2011 ◽  
Vol 335-336 ◽  
pp. 1141-1144 ◽  
Author(s):  
Yun Xiang He
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Drying Shrinkage ◽  
Recycled Aggregate ◽  
Structure Theory ◽  
Replacement Rate ◽  
Pore Characteristics ◽  
Cement Ratio ◽  
Mix Proportion ◽  
The Impact

Pore structure is one of the main influencing factors of materials drying shrinkage. C30 natural mix proportion is used as reference, the impact of replacement rate of recycled aggregate, the mixing amount of fly ash, water reducer, expansion agent and water-cement ratio on recycled aggregate concrete’s porosity and pore characteristics was studied. Based on the pore structure theory, the influence of porosity and pore characteristics on recycled aggregate concrete’s drying shrinkage is analyzed.

Improving strength, drying shrinkage, and pore structure of concrete using metakaolin

2007 ◽  
Vol 41 (5) ◽  
pp. 937-949 ◽  
Author(s):  
Erhan Güneyisi ◽  
Mehmet Gesoğlu ◽  
Kasım Mermerdaş
Keyword(s):  
Pore Structure ◽  
Drying Shrinkage
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