scholarly journals Performances of Cement Mortar Incorporating Superabsorbent Polymer (SAP) Using Different Dosing Methods

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1619 ◽  
Author(s):  
Yawen Tan ◽  
Huaxin Chen ◽  
Zhendi Wang ◽  
Cheng Xue ◽  
Rui He
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Tap Water ◽  
Mass Loss Rate ◽  
Drying Shrinkage ◽  
Superabsorbent Polymer ◽  
Water Desorption ◽  
Cement Ratio ◽  
Freeze Thaw ◽  
Water To Cement Ratio

Modified cement mortar was prepared by incorporating a superabsorbent polymer (SAP) with two kinds of dosing state, dry powdery SAP and swelled SAP (where the SAP has been pre-wetted in tap water), respectively. The mechanical properties, drying shrinkage and freeze–thaw resistance of the mortars were compared and analyzed with the variation of SAP content and entrained water-to-cement ratios. Additionally, the effect of SAP on the microstructure of mortar was characterized by scanning electron microscopy (SEM). The results indicate that agglomerative accumulation is formed in the voids of mortar after water desorption from SAP and there are abundant hydration products, most of which are C-S-H gels, around the SAP voids. The incorporation of the powdery SAP increases the 28 d compressive strength of the mortars by about 10% to 50%, while for the incorporation of swelled SAP, the 28 d compressive strength of the mortar can be increased by about −26% to 6%. At a dosage of 0.1% SAP and an entrained water–cement ratio of 0.06, the powdery SAP and the swelled SAP can reduce the mortar shrinkage rate by about 32.2% and 14.5%, respectively. Both the incorporation of powdery and swelled SAP has a positive effect on the freeze–thaw resistance of cement mortar. In particular, for powdery SAP with an entrained water-to-cement ratio of 0.06, the mass loss rate after 300 cycles is still lower than 5%.

Chloride Ingress Control and Promotion of Internal Curing in Concrete Using Superabsorbent Polymer

2021 ◽  
Vol 888 ◽  
pp. 67-75
Author(s):  
Ariel Verzosa Melendres ◽  
Napoleon Solo Dela Cruz ◽  
Araceli Magsino Monsada ◽  
Rolan Pepito Vera Cruz
Keyword(s):  
Compressive Strength ◽  
Cementitious Materials ◽  
Internal Curing ◽  
Mix Design ◽  
Chloride Ingress ◽  
Superabsorbent Polymer ◽  
Cement Slurry ◽  
Chloride Permeability ◽  
Cement Ratio ◽  
Water To Cement Ratio

Chloride ingress into concrete from the surrounding environment can result in the corrosion of the embedded steel reinforcement and cause damage to the concrete. Superabsorbent polymer (SAP) with fine particle size was incorporated into the structure of concrete for controlling the chloride ingress and improving its compressive strength via promotion of internal curing. The SAP used in this study was evaluated for its absorbency property when exposed to cementitious environment such as aqueous solution of Ca (OH)2 and cement slurry. The results were compared to that in sodium chloride solution, the environment where absorbency of most of the SAP found in the market are well studied. Results showed that although SAP absorbency decreased with increasing concentration of Ca (OH)2 and cement, the results suggest that water containing cementitious materials are able to be absorbed by SAP. Chloride ingress into 28-day cured concrete specimens were determined using Rapid Chloride Penetration Test (RCPT) method employing 60V DC driving force. Concrete samples with size of 50 mm height x 100 mm diameter were prepared using a M25 mix design with 0.4 and 0.45 water to cement ratios and different percentages of SAP such as 0.05%, 0.1% and 0.15% with respect to cement mass. Results showed that concrete with 0.15% SAP gave the best result with 14% less chloride permeability than concrete with no SAP for a 0.4 water to cement ratio. Concrete samples for compressive strength tests with size of 200 mm height x 100 mm diameter were prepared using the same mix design and percentages of SAP and cured for 28 days. Results showed that the best results for compressive strength was found at 0.1% SAP at a 0.4 water to cement ratio which can be attributed to internal curing provided by SAP.

Effect of Mica Content in Stone Powder of Manufactured Sand on Performance of Cement Mortar

2014 ◽  
Vol 1044-1045 ◽  
pp. 624-628
Author(s):  
Jie Quan Xing ◽  
Shu Lin Zhan ◽  
Xin Yu Li
Keyword(s):  
Compressive Strength ◽  
Loss Rate ◽  
Cement Mortar ◽  
Mass Loss Rate ◽  
Strength Loss ◽  
Freezing Resistance ◽  
River Sand ◽  
Manufactured Sand ◽  
Freeze Thaw ◽  
Different Content

This paper studies the influence on compressive strength, freezing resistance and microstructure of cement mortar with different content of mica in stone powder, in the tests, manufactured sand with high content of mica and natural river sand were mixed with different proportion, and the content of stone powder was the same in mixed sand. Experiment results indicate that, with the increasing of mica content in stone powder, 28d and 60d compressive strength of cement mortar decreases obvious, mass loss rate and strength loss rate with 50 freeze-thaw cycles increase a little. Microstructure of cement mortar with higher content of mica is not compactly by SEM, the internal defects of cement hardened pastes could be increased because of the flake mica which surface is smooth, and it will cause the spread of micro crack.

scholarly journals Compressive Strength of Cement Mortar Modified with Nano-Alumina in Correlation with Different Water-to-Cement Ratios and Curing Periods -A Statistical Analysis

2020 ◽  
Vol 7 (3) ◽  
pp. 79-98
Author(s):  
Muhammed Abdullah ◽  
◽  
Serwan Rafiq ◽  
Keyword(s):  
Compressive Strength ◽  
Mechanical Performance ◽  
Cement Mortar ◽  
Nonlinear Modeling ◽  
Dry Weight ◽  
Coefficient Of Determination ◽  
Cement Ratio ◽  
Curing Period ◽  
Water To Cement Ratio ◽  
Nano Alumina

One promising insight to extended service life of cement mortar and improve it is durability by assimilating nano mechanism into the cement-based materials. Regardless of many research studies on the effect of nano alumina on the mechanical performance of cement mortar, there has not been a widespread study examining the effect of nano Al2O3, curing period (t), and water-to-cement ratio (w/c) on the compressive strength (σc) of cement mortar. Consequently, this study explores the subject matter which could be helpful for the building and construction field. In this study, the data collected on the compressive strength of the cement mortar modified with different percentages of nano alumina ranging from 0.5% to 13.5% (by dry weight of the cement) were gathered from the literature. A nonlinear modeling NLM and statistical data analysis were performed on above 500 assembled data. The w/c ratio of the cement mortar varied from 0.3% to 0.79%, and the compressive strength of cement mortar modified with nano alumina and cured for 1,7 and 28 up to 90 days leads to high strength ranged from (10 MPa to 68 MPa). The result of NLM showed that curing period has the highest effect on the compressive strength in combination with water to cement ratio and percentage of nano alumina replacement with a coefficient of determination (R2) of 0.85.

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.

scholarly journals Graphene Nanoplatelets Impact on Concrete in Improving Freeze-Thaw Resistance

2019 ◽  
Vol 9 (17) ◽  
pp. 3582 ◽  
Author(s):  
Guofang Chen ◽  
Mingqian Yang ◽  
Longjun Xu ◽  
Yingzi Zhang ◽  
Yanze Wang
Keyword(s):  
Compressive Strength ◽  
Ordinary Portland Cement ◽  
Graphene Nanoplatelets ◽  
Compressive Property ◽  
Cement Ratio ◽  
Freeze Thaw ◽  
Ordinary Concrete ◽  
Water To Cement Ratio ◽  
Chinese Standard ◽  
Better Than

Graphene nanoplatelets (GNP) is a newly nanomaterial with extraordinary properties. This paper investigated the effect of GNP on the addition on freeze–thaw (F–T) resistance of concrete. In this experimental study, water to cement ratio remained unchanged, a control mixture without GNP materials and the addition of GNP was ranging from 0.02% to 0.4% by weight of ordinary Portland cement was prepared. Specimens were carried out by the rapid freeze-thaw test, according to the current Chinese standard. The workability, compressive strength, visual deterioration and mass loss of concrete samples were evaluated. Scanning electron microscopy also applied in order to investigate the micromorphology inside of the concrete. The results showed that GNP concrete has a finer pore structure than ordinary concrete; moreover, the workability of GNP concrete reduced, and the compressive strength of specimens was enhanced within the appropriate range of GNP addition; in addition, GNP concrete performed better than the control concrete in the durability of concrete exposed to F-T actions. Specimens with 0.05% GNP exhibited the highest compressive property after 200 F–T cycles compared with other samples.

Mechanical Properties and Microstructures of Cement Mortar Modified with Styrene-Butadiene Polymer Emulsion

2010 ◽  
Vol 168-170 ◽  
pp. 190-194 ◽  
Author(s):  
Zhen Jun Wang ◽  
Rui Wang ◽  
Yu Bin Cheng
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Cement Mortar ◽  
Strength Increase ◽  
Polymer Emulsion ◽  
Cement Ratio ◽  
Cement Mortars ◽  
Water To Cement Ratio ◽  
Styrene Butadiene

In this paper, styrene-butadiene polymer emulsion SD622S was adopted to modify cement mortar; mechanical properties of cement mortars were studied and microstructures was analyzed by means of Scanning Electron Microscope (SEM) and Specific Surface Area & Pore Distribution Analyzer. The results show that in contrast to ordinary cement mortar, if water to cement ratio (W/C) is constant, compressive strength of modified cement mortar can decrease, while flexural strength and toughness, ratio of compressive strength to flexural strength, increase with the increase of polymer to cement ratio in mass (P/C) at 7 and 28 curing days. With the increase of P/C, net structure made from polymer and cement hydration products is developed and pore whose size is smaller than 200Å begins to increase, which indicates pore diameters in modified cement mortar change to be finer. So microstructures of modified cement mortar become denser and display higher toughness.

scholarly journals Combustion and Mechanical Properties of Polymer-Modified Cement Mortar at High Temperature

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Hyung-Jun Kim ◽  
Won-Jun Park
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Heat Release ◽  
Cement Mortar ◽  
Mass Loss Rate ◽  
Polymer Content ◽  
Cement Ratio ◽  
Combustion Properties ◽  
Polymer Type

Although polymer-modified cement mortar (PCM) has been extensively used as finishing and repairing material, it is necessary to understand its combustion properties and mechanical properties at high temperature. This study evaluated the combustion characteristics with varying experimental parameters such as polymer type, unit polymer content, polymer-cement ratio, and thickness of the specimen. This study also evaluated the compressive strength and elastic modulus of PCMs with focus on the effects of the type of polymer, unit polymer content, and polymer-cement ratio. As a result, the incombustibility of the PCM was in the following order: SBR < VVA < EVA. After heating end, the mass loss rate of the PCM was less than 30%, regardless of the polymer type, unit polymer content, and W/C. In heat release rate test, the higher the unit polymer content, the greater the total heat release, regardless of the difference in W/C. The PAE series showed excellent fire resistance in the temperature range of 200~400°C. PCMs with a unit polymer content of 5%, modified with EVA and PAE, showed outstanding compressive strength at 200~400°C. At elevated temperature, the modulus of elasticity of PCM declined with an increase in the unit polymer content, regardless of the polymer type.

scholarly journals Experimental Study on Effective Chloride Diffusion Coefficient of Cement Mortar by Different Electrical Accelerated Measurements

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 240
Author(s):  
Jianlan Chen ◽  
Jiandong Wang ◽  
Rui He ◽  
Huaizhu Shu ◽  
Chuanqing Fu
Keyword(s):  
Diffusion Coefficient ◽  
Cement Mortar ◽  
Early Stage ◽  
Chloride Concentration ◽  
Chloride Diffusion ◽  
Chloride Diffusion Coefficient ◽  
Cement Ratio ◽  
Water To Cement Ratio ◽  
Good Consistency ◽  
Determination Methods

This study investigated the effective chloride diffusion coefficient of cement mortar with different water-to-cement ratio (w/c) under electrical accelerated migration measurement. The cumulative chloride concentration in anode cell solution and the cumulative chloride concentration drop in the cathode cell solution was measured by RCT measurement and the results were further used to calculate the chloride diffusion coefficient by Nordtest Build 355 method and Truc method. The influence of w/c on cement mortar’s chloride coefficient was investigated and the chloride diffusion coefficient under different determination methods were compared with other researchers’ work, a good consistency between this work’s results and literatures’ results was obtained. The results indicated that the increased w/c of cement mortar samples will have a higher chloride diffusion coefficient. The cumulative chloride concentration drop in the cathode cell solution will have deviation in early stage measurement (before 60 h) which will result in overestimation of the effective chloride diffusion coefficient.

Durability of concrete containing chloride-based accelerating admixtures

1990 ◽  
Vol 17 (1) ◽  
pp. 102-112
Author(s):  
T. Rezansoff ◽  
D. Stott
Keyword(s):  
Calcium Chloride ◽  
Dynamic Modulus ◽  
Linseed Oil ◽  
Standard Test ◽  
Test Method ◽  
Concrete Durability ◽  
Freezing And Thawing ◽  
Cement Ratio ◽  
Freeze Thaw ◽  
Water To Cement Ratio

The influence of CaCl2 or a chloride-based accelerating admixture on the freeze–thaw resistance of concrete was evaluated. Three air entrained mix designs were investigated using ASTM C666-84, Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing. All mix designs were similar, using cement contents of 340–357 kg/m3 of concrete, except for the addition of either 2% calcium chloride or 2% High Early Pozzolith, while no accelerating admixture was added to the control mix. The entire test program was repeated four times with water-to-cement ratio of 0.46 and three times with the ratio of 0.43. For the Pozzolith-accelerated concrete, half the samples were coated with boiled linseed oil in all seven series. For the control (unaccelerated) concrete, half the samples were coated with boiled linseed oil in one series for each water-to-cement ratio. Performance was monitored using the dynamic modulus of elasticity as obtained from transverse resonant frequency measurements. Weight loss of the specimens was also measured. Only the control samples (no accelerators) showed sufficient durability to satisfy the standard of maintaining at least 60% of the original dynamic modulus after 300 cycles of alternate freezing and thawing. Sealing with linseed oil showed inconsistent improvement in the durability in the various test series when defined in terms of the dynamic modulus; however, weight losses were the lowest of all categories and surface scaling was minimal. Key words: concrete, durability, freeze–thaw testing, calcium chloride, admixtures, sealants, air void system.

Autoclaved Brick from Steel Slag and Silicon Tailings

2014 ◽  
Vol 878 ◽  
pp. 194-198 ◽  
Author(s):  
Peng Guan Li ◽  
Feng Qing Zhao
Keyword(s):  
Compressive Strength ◽  
Total Mass ◽  
Bending Strength ◽  
Steel Slag ◽  
Drying Shrinkage ◽  
Load Bearing ◽  
Volume Stability ◽  
Freeze Thaw

The load-bearing brick is made from steel slag and silicon tailings by pressing and autoclaving process. Because of the volume stability, steel slag was ground to above 320 m2/kg and wet cured in 50-60°C at 12-24 hours in the present of additives, before pressure forming and autoclaving process. Tailings account for 63% of the total mass of the brick, while steel slag 30 %. The compressive strength of the brick was up to 13.1MPa, bending strength 3.2MPa, and with low drying shrinkage and good freeze-thaw resistance. The application conditions were discussed.

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