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

This paper will focus on developing a sort of concrete shrinkage-reducing agents that are generally some surfactants on the basis of some tests. By reference to the main chemical components of some domestic and foreign agents, the following chemicals are initially selecting : tert-butyl alcohol, triethanolamine and polyvinyl alcohol, and then some experiments about these substances were made, including liquid surface tension test, high-strength cement mortar shrinkage test, mortar strength test. Finally, the medicals that can significantly reduce drying shrinkage deformation but have little effect on the strenth of concrete blocks,are selected out as available concrete shrinkage-reducing agents.

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

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.125683 ◽

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

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.629-630.443 ◽

2014 ◽

Vol 629-630 ◽

pp. 443-448 ◽

Cited By ~ 8

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.

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The effects of waste glass cullets and nanosilica on the long-term properties of cement mortars

E3S Web of Conferences ◽

10.1051/e3sconf/20184900102 ◽

2018 ◽

Vol 49 ◽

pp. 00102 ◽

Cited By ~ 3

Author(s):

Katarzyna Skoczylas ◽

Teresa Rucińska

Keyword(s):

Mechanical Properties ◽

Beneficial Effect ◽

Construction Industry ◽

Adhesive Strength ◽

Drying Shrinkage ◽

Waste Glass ◽

Curing Conditions ◽

Freeze Thaw ◽

Cement Mortars

This study presents experimental results on the effects of nanosilica and waste glass cullets on the long-term mechanical properties and durability of cement mortars. Three groups of cement mortars were prepared, where natural aggregate was replaced in 0% (R), 50% (RWG) and 100% (WG) with waste glass cullets by volume. Each group was modified with the nanosilica admixture by 0%, 1% and 3% by the weight of cement. Furthermore, superplasticizer was incorporated in order to improve the workability of mortars. Subsequently to the preparation and curing of specimens, mechanical properties after 7, 28 and 365 days, freeze-thaw resistance, adhesive strength, abrasion resistance, and drying shrinkage (in two types of curing conditions) were evaluated. The results confirmed the applicability of waste glass in the construction industry as well as the beneficial effect of nanosilica on the mechanical properties of mortars.

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Effect of Nanosilica Particle Size on the Water Permeability, Abrasion Resistance, Drying Shrinkage, and Repair Work Properties of Cement Mortar Containing Nano-SiO2

Advances in Materials Science and Engineering ◽

10.1155/2017/4213690 ◽

2017 ◽

Vol 2017 ◽

pp. 1-11 ◽

Cited By ~ 12

Author(s):

Sattawat Haruehansapong ◽

Tawich Pulngern ◽

Somchai Chucheepsakul

Keyword(s):

Particle Size ◽

Water Permeability ◽

Abrasion Resistance ◽

Cement Mortar ◽

Drying Shrinkage ◽

Particle Sizes ◽

Repair Work ◽

Durability Properties ◽

Cement Mortars ◽

Nanosilica Particle

This work presents the effect of nanosilica particle sizes on durability properties and repair work properties of cement mortar containing nanosilica (NS). Three different NS particle sizes of 12, 20, and 40 nm were used and compared with those of cement mortar without NS and cement mortar with silica fume (SF). Interesting results were obtained in which the particle size of NS affected directly the abrasion resistance and water permeability. NS with particle size of 40 nm is the optimum size and gave the highest abrasion resistance and water permeability. For repair work properties, cement mortars containing NS (12 and 20 nm) and SF experienced higher drying shrinkage than that of cement mortar without NS and then presented cracking behavior and debonding between the cement mortars and concrete substrate. Cement mortar containing 40 nm of NS gave the lowest drying shrinkage, the lowest crack number, and the highest adhesive strength. These results indicate that the particle size of NS affected not only the durability properties but also the repair work properties of cement mortar.

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INFLUENCE OF PORTLAND CEMENT AND SHRINKAGE REDUCING AGENTS TO DRYING SHRINKAGE OF CONCRETE

Journal of Structural and Construction Engineering (Transactions of AIJ) ◽

10.3130/aijs.77.1167 ◽

2012 ◽

Vol 77 (678) ◽

pp. 1167-1173

Author(s):

Yoshiaki OHNO ◽

Yoshihiro MASUDA ◽

Tadatsugu KAGE

Keyword(s):

Portland Cement ◽

Drying Shrinkage ◽

Reducing Agents

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Fluid Transport Mechanisms in Portland Cement Mortar Modified with PVA and Nano Montmorillonite

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.687.311 ◽

2013 ◽

Vol 687 ◽

pp. 311-315 ◽

Cited By ~ 3

Author(s):

Teresa María Piqué ◽

Luis Fernandez Luco ◽

Analía Vázquez

Keyword(s):

Tensile Strength ◽

Portland Cement ◽

Construction Industry ◽

Fluid Transport ◽

Cement Mortar ◽

Drying Shrinkage ◽

Cement Matrix ◽

Poly Vinyl Alcohol ◽

Cement Mortars ◽

Compressive And Flexural Strengths

The development of new materials for specific applications is an increasing field in the construction industry, so is the employment of nanotechnology for this goal. When poly(vinyl alcohol) (PVA) is added to a Portland cement mortar, a film is formed in between the hydration products. This film has low elasticity modulus and high tensile strength and it enhances the mortar’s mechanical properties in the fresh and hardened states. The addition of nano montmorillonites (MMT) gives the polymer a better compatibility with the cement matrix. In this work, the changes in the microstructure of Portland cement mortars modified with PVA and PVA with MMT are assessed by means of transport of fluids capacity as an indicator. The reference is a standard mortar according to EN 196-1. The parameters measured are: weight loss under drying and air permeability. Complementary measures, such as compressive and flexural strengths and drying shrinkage have also been performed. From the obtained results, it can be concluded that the inclusion PVA + MMT to Portland cement mortar doesn’t affect the microstructure, when compared with Portland cement mortar with PVA, and even increase its tensile strength.

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