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

Effect of Colloidal Nano-Silica on the Mechanical and Durability Performances of Mortar

2014 ◽  
Vol 629-630 ◽  
pp. 443-448 ◽  
Author(s):  
Hong Jian Du ◽  
Sze Dai Pang
Keyword(s):  
Compressive Strength ◽  
Drying Shrinkage ◽  
Pozzolanic Reaction ◽  
Nano Silica ◽  
Cement Ratio ◽  
Durability Properties ◽  
Cement Mortars ◽  
Water To Cement Ratio ◽  
Water Sorptivity ◽  
Mixing Water

s. The mechanical and durability properties of cement mortars with colloidal nanosilica (CNS) were investigated experimentally. Reference mortar with a low water-to-cement ratio of 0.30 was used in this study. The influence of CNS was evaluated by adding 0.5, 1.0, 1.5 and 2.0% of CNS by weight of cement. CNS was first stirred in the mixing water for 2 minutes before added to cement and sand. Superplasticizer was used to maintain the same flowability. Results showed that the compressive strength consistently increases with higher dosage of CNS at all the curing ages, due to both hydration acceleration and pozzolanic reaction. With the increase in CNS, the migration coefficient and water sorptivity consistently decreased; with 2% of CNS, the migration coefficient and water sorptivity were reduced by 45% and 30% respectively in comparison with the reference mortar. The improved durability could be explained by the reduction and refinement in the porosity, which can be attributed to nanofiller effect and pozzolanic reaction of nanosilica. Furthermore, the addition of CNS could reduce the drying shrinkage by densifying the microstructure in the cement paste, which has not been reported previously.

Short-term studies on the durability of laterized concrete and laterite-cement mortars

1990 ◽  
Vol 25 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Fola Lasisi ◽  
J.A. Osunade ◽  
A.O. Adewale
Keyword(s):  
Short Term ◽  
Cement Mortars

scholarly journals SIZE EFFECT ON THE ULTIMATE DRYING SHRINKAGE OF CEMENT MORTAR: 1-YEAR EXPERIMENT AND NUMERICAL MODELING

2021 ◽  
Vol 30 ◽  
pp. 1-6
Author(s):  
Lenka Dohnalová ◽  
Petr Havlásek ◽  
Vít Šmilauer ◽  
Pavel Reiterman ◽  
Vendula Davidová
Keyword(s):  
Size Effect ◽  
Cement Mortar ◽  
Drying Shrinkage ◽  
Small Scale ◽  
First Year ◽  
Design Codes ◽  
Laboratory Measurements ◽  
Short Term ◽  
Dependent Behavior ◽  
Creep And Shrinkage

The magnitude and time evolution of shrinkage are influenced by numerous factors which are implemented in the design codes often in a different way. The time-dependent behavior of concrete in structures sensitive to creep and shrinkage should be verified by means of short-term laboratory measurements. Extrapolation of drying shrinkage from short-term measurements is an illposed problem. The process is extremely slow but can be accelerated by reducing the specimen size. The knowledge of the size-effect on drying shrinkage is a necessity to establish the transition from the laboratory to the structural size. In the literature, the experimental data on such size-effect are insufficient. For this reason a new experiment was developed to study this phenomenon on small-scale specimens made of cement mortar and the results from the first year are summarized in this paper. The measured data are validated by coupled FEM hygro-mechanical simulations.

scholarly journals Influence of Nano-silica on the Leaching Attack upon Photocatalytic Cement Mortars

2019 ◽  
Vol 13 (1) ◽  
Author(s):  
Atta-ur-Rehman ◽  
Abdul Qudoos ◽  
Sadam Hussain Jakhrani ◽  
Hong Gi Kim ◽  
Jae-Suk Ryou
Keyword(s):  
Nano Silica ◽  
Cement Mortars

scholarly journals Drying shrinkage of cement mortars treated with shrinkage-reducing agents.

1989 ◽  
Vol 38 (431) ◽  
pp. 926-931
Author(s):  
Katsunori DEMURA ◽  
Yoshihiko OHAMA ◽  
Masashi MORIKAWA ◽  
Masafumi ACHIWA
Keyword(s):  
Drying Shrinkage ◽  
Reducing Agents ◽  
Cement Mortars

Study on the reinforcing mechanisms of nano silica to cement-based materials with theoretical calculation and experimental evidence

2016 ◽  
Vol 50 (29) ◽  
pp. 4135-4146 ◽  
Author(s):  
Liqing Zhang ◽  
Ning Ma ◽  
Yunyang Wang ◽  
Baoguo Han ◽  
Xia Cui ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Theoretical Calculation ◽  
Interfacial Transition Zone ◽  
Cement Matrix ◽  
Nano Silica ◽  
X Ray ◽  
Cement Mortars ◽  
Cement Based Materials ◽  
Compressive And Flexural Strengths ◽  
Curing Age

Cement mortars with different contents of nano silica (NS) were fabricated and tested. Their compressive and flexural strengths showed significant increases. Theoretical calculation and thermogravimetry (TG) analysis, scanning electron microscope (SEM) and X-Ray powder diffraction (XRD), and electrical resistivity test were used to analyze the reinforcing mechanisms of NS. Theoretically, consumed calcium hydroxide (CH) increases with NS content, which indicates that NS has huge potential to react with CH. According to the results of TG, the amount of consumed CH increases and agrees with theoretical calculation when the content of NS is less than 1.5%. However, a plateau is achieved for the mass of consumed CH in results of TG when the content of NS exceeds 1.5%. SEM shows that NS can make matrix dense and also reduce the size of CH in matrix beside interfacial transition zone (ITZ). The results of XRD prove that NS can change the tendency of crystal of CH in cement matrix. However, the change degree of tendency of crystal of CH in cement matrix is lower than that in ITZ. The change trends of electrical resistivity with increasing NS content and curing age are similar with those of flexural and compressive strengths. This indicates that electrical resistivity can reflect strength and structural compactness of cement matrix.

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