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.

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 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%.

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.

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.

scholarly journals Use of Recycled Tyre Rubber in Non-structural Concrete

2018 ◽  
Vol 203 ◽  
pp. 06001
Author(s):  
Muhammad Bilal Waris ◽  
Hussain Najwani ◽  
Khalifa Al-Jabri ◽  
Abdullah Al-Saidy
Keyword(s):  
Compressive Strength ◽  
Water Absorption ◽  
Coarse Aggregate ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Structural Concrete ◽  
Cement Ratio ◽  
Mix Proportion ◽  
Water To Cement Ratio ◽  
Concrete Blocks

To manage tyre waste and conserve natural aggregate resource, this research investigates the use of waste tyre rubber as partial replacement of fine aggregates in non-structural concrete. The research used Taguchi method to study the influence of mix proportion, water-to-cement ratio and tyre rubber replacement percentage on concrete. Nine mixes were prepared with mix proportion of 1:2:4, 1:5:4 and 1:2.5:3; water-to-cement ratio of 0.25, 0.35 and 0.40 and rubber to fine aggregate replacement of 20%, 30% and 40%. Compressive strength and water absorption tests were carried out on 100 mm cubes. Compressive strength was directly proportional to the amount of coarse aggregate in the mix. Water-to-cement ratio increased the strength within the range used in the study. Strength was found to be more sensitive to the overall rubber content than the replacement ratio. Seven out of the nine mixes satisfied the minimum strength requirement for concrete blocks set by ASTM. Water absorption and density for all mixes satisfied the limits applicable for concrete blocks. The study indicates that mix proportions with fine to coarse aggregate ratio of less than 1.0 and w/c ratio around 0.40 can be used with tyre rubber replacements of up to 30 % to satisfy requirements for non-structural concrete.

scholarly journals Evaluation the effect of lime on the plastic and hardened properties of cement mortar and quantified using Vipulanandan model

2019 ◽  
Vol 9 (1) ◽  
pp. 468-480 ◽  
Author(s):  
Warzer Qadir ◽  
Kawan Ghafor ◽  
Ahmed Mohammed
Keyword(s):  
Cement Mortar ◽  
Plastic Properties ◽  
Cement Ratio ◽  
Lime Content ◽  
Setting Times ◽  
Water To Cement Ratio ◽  
Bond Strengths ◽  
Hardened Properties ◽  
Compressive And Flexural Strengths ◽  
The Relationship

AbstractIn this study, the effect of lime content (L %) on the plastic properties such as water-cement ratio (w/c), setting times, flowability, compressive, flexural and bond strengths of cement mortar were investigated. Based on the information in the literature the amount of lime varied between 0 to 45% (by weight of cement). The experimental results were compared with the data collected from different research studies and quantified using two different models. The plastic and hardened properties of the cement mortar modified with different percentage of lime were conducted according to the ASTM and BS standards. Based on the literature data the water to cement ratio (w/c) ranged between 0.3-0.74 percent, the w/c of 0.5 was selected in this study. The compressive and flexural strengths of cement mortar modified with lime up to 28 days of curing were ranged between 3 MPa to 65 MPa and 2 MPa to 12 MPa respectively. The compressive, flexural and bond strengths of the cement mortar decreased with increasing lime content. Vipulanandan correlation model was used to correlate the relationship between lime with consistency, setting times, flowability and compressive strength of cement mortar. Compressive and flexural strengths of cement mortar modified with lime were quantified very well as a function of w/c, lime content and curing time using nonlinear relationship.

Effects of Fly Ash Addition on Compressive Strength and Flexural Strength of Foamed Cement Composites

2013 ◽  
Vol 795 ◽  
pp. 664-668 ◽  
Author(s):  
Roshasmawi Abdul Wahab ◽  
Mohd Noor Mazlee ◽  
Shamsul Baharin Jamaludin ◽  
Khairul Nizar Ismail
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Cement Composites ◽  
Volume Percent ◽  
Foaming Agent ◽  
Cement Ratio ◽  
Water To Cement Ratio

In this study, the mixing of polystyrene (PS) beads and fly ash as a sand replacement material in foamed cement composites (FCC) has been investigated. Specifically, the mechanical properties such as compressive strength and flexural strength were measured. Different proportions of fly ash were added in cement composites to replace the sand proportion at 3 wt. %, 6 wt. %, 9 wt. % and 12 wt. % respectively. The water to cement ratio was fixed at 0.65 meanwhile ratios of PS beads used was 0.25 volume percent of samples as a foaming agent. All samples at different mixed were cured at 7 and 28 days respectively. Based on the results of compressive strength, it was found that the compressive strength was increased with the increasing addition of fly ash. Meanwhile, flexural strength was decreased with the increasing addition of fly ash up to 9 wt. %. The foamed cement composites with 12 wt. % of fly ash produced the highest strength of compressive strength meanwhile 3 wt. % of fly ash produced the highest strength of flexural strength.

Preparation and Mechanical Performance of Sulpoaluminate Cement by Using Industrial Solid Wastes

2017 ◽  
Vol 726 ◽  
pp. 510-514
Author(s):  
Shi Zhen Zhao ◽  
Feng Lan Han ◽  
Gui Qun Liu ◽  
Mao Hui Li ◽  
Yu Jie Chen
Keyword(s):  
Fly Ash ◽  
Mechanical Performance ◽  
Cement Mortar ◽  
Raw Materials ◽  
Industrial Process ◽  
Chemical Characteristic ◽  
Cement Clinker ◽  
Hydration Mechanism ◽  
Water To Cement Ratio ◽  
Physical And Chemical

By using Mn slag, Mg slag and Fly ash which comes from industrial process in Ningxia province as raw materials, the sulpoaluminate cement was prepared via sintering raw materials in a furnace. The physical and chemical characteristic of sulpoaluminate cement clinker was tested. The optimal proportion of clinkers is also determined by the results of phase composition, microstructure and hydration mechanism. The results shows that when the mixed ratio of Mn slag, Mg slag and Fly ash is 21%, 21% and 0% respectively in the raw materials and the calcination temperature is 1300 °C for 30 min, sulphoaluminate cement clinker with maximum amount of C4A3S, C2S and C4AF was prepared. Then, natural gypsum was added into the clinker powder with a ratio of 15% to make cement materials. When water to cement ratio is 0.5 and cement to sand ratio is 1:3, the cement mortar obtain a compressive strength of 22.22 MPa at 3d, 31.2 MPa at 7 d, and the flexural strength of 3.86MPa at 3d, and 4.83 MPa at 7d respectively.

Performance of ilmenite concrete at sustained elevated temperatures

1988 ◽  
Vol 15 (5) ◽  
pp. 776-783
Author(s):  
H. S. Wilson
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
High Temperature ◽  
Flexural Strength ◽  
Key Words ◽  
Elevated Temperatures ◽  
Cement Ratio ◽  
Nondestructive Tests ◽  
High Temperature Mechanical Properties ◽  
Curing Period

Two similar mixes were made with cement contents of about 350 kg/m3 and a water–cement ratio of 0.50. The concrete specimens, moist cured for 7 days, were cured in air for 28 and 120 days, respectively, prior to heating. The exposure temperatures were 75, 150, 300, and 450 °C. The periods of exposure at each temperature were 2, 30, and 120 days.The compressive strengths, before heating, of the specimens cured for 35 and 120 days were 41.0 and 46.2 MPa, respectively, and the flexural strengths were 4.9 and 5.8 MPa. Compared with those strengths, the strengths of the specimens heated for 30 days or more increased at 75 °C but decreased at higher temperatures. The losses increased with increase in temperature, reaching about 30% at 450 °C.The flexural strength of the concrete cured in air for 28 days was more adversely affected than was the compressive strength. The flexural and compressive strengths of the concrete cured in air for 120 days were affected to about the same degree. The longer curing period had little effect on the relative losses in compressive strength, but the longer curing period reduced the loss in flexural strength. In most applications, the loss in strength could be compensated by proportioning the mix to overdesign for strength. Key words: high-density concrete, ilmenite, aggregates, high temperature, mechanical properties, nondestructive tests.

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