Effect of Humidity on the Properties of Cement Mortars with a Crystalline Additive

2018 ◽  
Vol 276 ◽  
pp. 53-59 ◽  
Author(s):  
Nikol Žižková ◽  
Lenka Nevřivová ◽  
Matěj Lédl
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Secondary Crystallization ◽  
Polypropylene Fibres ◽  
Cement Mortars ◽  
Different Levels

The paper focuses on examining the properties of mortars in which secondary crystallization (crystalline additive) was used. Laboratory tests have found that the effect of secondary crystallization is influenced by conditions in which specimens have been stored during the first 28 days. The investigation focused on the physical-mechanical properties and microstructure of mortar specimens containing a crystalline additive and polypropylene fibres stored at different levels of humidity for 28 days. The influence of crystalline additive on strength was studied as well and the results show that crystalline additives improves the 28-day strength of the mortars.

Incorporation of Iraqi Rocks in the Production of Eco-Friendly Cement Mortar

2020 ◽  
Vol 38 (10A) ◽  
pp. 1522-1530
Author(s):  
Rawnaq S. Mahdi ◽  
Aseel B. AL-Zubidi ◽  
Hassan N. Hashim
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Water Absorption ◽  
Structural Properties ◽  
Mechanical Milling ◽  
Cement Mortar ◽  
Cement Mortars

This work reports on the incorporation of Flint and Kaolin rocks powders in the cement mortar in an attempt to improve its mechanical properties and produce an eco-friendly mortar. Flint and Kaolin powders are prepared by dry mechanical milling. The two powders are added separately to the mortars substituting cement partially. The two powders are found to improve the mechanical properties of the mortars. Hardness and compressive strength are found to increase with the increase of powders constituents in the cement mortars. In addition, the two powders affect water absorption and thermal conductivity of the mortar specimens which are desirable for construction applications. Kaolin is found to have a greater effect on the mechanical properties, water absorption, and thermal conductivity of the mortars than Flint. This behavior is discussed and analyzed based on the compositional and structural properties of the rocks powders.

LABORATORY TESTS OF THE PHYSICAL-MECHANICAL PROPERTIES OF MATERIALS FOR REMEDIAL JOBS

2020 ◽  
pp. 58-63
Author(s):  
M.A. Druzhinin ◽  
◽  
G.V. Okromelidze ◽  
O.V. Garshina ◽  
I.A. Kudimov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Mechanical Properties Of Materials ◽  
Properties Of Materials

Influence of the Composition of Cement Mortars Modified by Lime or Polymers on the Mechanical Properties and Microstructure of Mortars

2013 ◽  
Vol 592-593 ◽  
pp. 647-650 ◽  
Author(s):  
Małgorzata Lenart
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Reinforced Concrete ◽  
Flexural Strength ◽  
Polyvinyl Alcohol ◽  
Polymer Composites ◽  
Adhesion Strength ◽  
Hardened Cement ◽  
Cement Mortars ◽  
Styrene Butadiene

Cement – polymer composites are nowadays widely used in repair systems not only in case of concrete or reinforced concrete constructions but also in masonry. Polymers addition for example already at 5% m.c. modifies the structure of the cement – polymer composite in a way that many of the mechanical properties such as flexural strength, tensile strength or adhesion to substrates are improved. The paper presents the results of tests such as flexural, compressive or adhesion strength to ceramic substrate of hardened cement mortars with different composition, as well as selected cement mortars modified by two polymers: polyvinyl alcohol and styrene – butadiene polymer dosed at 5 % m.c. Four types of cement mortars modified by lime (component used in historical constructions as well as in contemporary masonry mortars) are also examined for comparison.

scholarly journals Mechanical properties of dental restorative materials: relative contribution of laboratory tests

2003 ◽  
Vol 11 (3) ◽  
pp. 162-167 ◽  
Author(s):  
Linda Wang ◽  
Paulo Henrique Perlatti D'Alpino ◽  
Lawrence Gonzaga Lopes ◽  
José Carlos Pereira
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Clinical Performance ◽  
Dental Materials ◽  
Correct Selection ◽  
Relative Contribution ◽  
Dental Restorative Materials ◽  
Restorative Materials ◽  
Dental Restorative ◽  
Selection Of

A wide variety of dental products that are launched on the market becomes the correct selection of these materials a difficult task. Although the mechanical properties do not necessarily represent their actual clinical performance, they are used to guide the effects of changes in their composition or processing on these properties. Also, these tests might help somehow the clinician to choose once comparisons between former formulations and new ones, as well as, with the leading brand, are highlighted by manufactures. This paper presents a review of the most important laboratory tests. In this manner, the knowledge of these tests will provide a critical opinion related to the properties of different dental materials.

scholarly journals Post-Processing Time Dependence of Shrinkage and Mechanical Properties of Injection-Molded Polypropylene

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 22
Author(s):  
Artur Kościuszko ◽  
Dawid Marciniak ◽  
Dariusz Sykutera
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Injection Molding ◽  
Accelerated Aging ◽  
Mold Temperature ◽  
Degree Of Crystallinity ◽  
Injection Mold ◽  
Secondary Crystallization ◽  
Scanning Calorimetry ◽  
Injection Molded

Dimensions of the injection-molded semi-crystalline materials (polymeric products) decrease with the time that elapses from their formation. The post-molding shrinkage is an effect of secondary crystallization; the increase in the degree of polymer crystallinity leads to an increase in stiffness and decrease in impact strength of the polymer material. The aim of this study was to assess the changes in the values of post-molding shrinkage of polypropylene produced by injection molding at two different temperatures of the mold (20 °C and 80 °C), and conditioned for 504 h at 23 °C. Subsequently, the samples were annealed for 24 h at 140 °C in order to conduct their accelerated aging. The results of shrinkage tests were related to the changes of mechanical properties that accompany the secondary crystallization. The degree of crystallinity of the conditioned samples was determined by means of density measurements and differential scanning calorimetry. It was found that the changes in the length of the moldings that took place after removal from the injection mold were accompanied by an increase of 20% in the modulus of elasticity, regardless of the conditions under which the samples were made. The differences in the shrinkage and mechanical properties of the samples resulting from mold temperature, as determined by tensile test, were removed by annealing. However, the samples made at two different injection mold temperature values still significantly differed in impact strength, the values of which were clearly higher for the annealed samples compared to the results determined for the samples immediately after the injection molding.

scholarly journals Effect of halloysite nanoclay on mechanical properties, thermal behavior and microstructure of cement mortars

2013 ◽  
Vol 48 ◽  
pp. 97-104 ◽  
Author(s):  
Nima Farzadnia ◽  
Abang Abdullah Abang Ali ◽  
Ramazan Demirboga ◽  
Mohammed Parvez Anwar
Keyword(s):  
Mechanical Properties ◽  
Thermal Behavior ◽  
Cement Mortars

Effect of Pearlite Structure on the Mechanical Properties of Microalloyed Hypereutectoid Steels

2005 ◽  
Vol 500-501 ◽  
pp. 737-744 ◽  
Author(s):  
A.M. Elwazri ◽  
Steve Yue
Keyword(s):  
Mechanical Properties ◽  
Structural Evolution ◽  
Salt Bath ◽  
Austenite Grain Size ◽  
Boundary Area ◽  
Austenite Grain ◽  
Heat Treated ◽  
Hypereutectoid Steels ◽  
The Relationship ◽  
Different Levels

The relationship between mechanical properties and pearlite microstructure was investigated using various heat treatments on a hypereutectoid steels containing 1% carbon with different levels of vanadium and silicon. Specimens were heat treated at various temperatures ranging from 900 to 1200°C and transferred to salt bath conditions at 550, 580 and 620°C to examine the structural evolution of pearlite. The results show that the thickness of the cementite network increases with increasing reheat temperature. This is likely due to the larger austenite grain size reducing the grain boundary area available for proeutectoid cementite nucleation. It was found that the vanadium and silicon additions increased the strength of hypereutectoid steels through refinement of the microstructure and precipitation strengthening.

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