Production of polycarboxylate-ether superplasticizer (PCE) coated sand with modified hardened properties in cement mortar

2020 ◽  
Vol 245 ◽  
pp. 118442 ◽  
Author(s):  
Ahmed Tareq Noaman ◽  
Mayyadah S. Abed ◽  
Alaa A. Abdul Hamead
Keyword(s):  
Cement Mortar ◽  
Hardened Properties ◽  
Coated Sand ◽  
Polycarboxylate Ether

scholarly journals Preparation and piezoresistivity of carbon nanotube-coated sand reinforced cement mortar

2020 ◽  
Vol 9 (1) ◽  
pp. 1445-1455
Author(s):  
Song Gao ◽  
Jianlin Luo ◽  
Jigang Zhang ◽  
Fei Teng ◽  
Chao Liu ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Cement Mortar ◽  
Aqueous Suspension ◽  
Ac Impedance ◽  
Stress Sensitivity ◽  
Multiwall Carbon Nanotube ◽  
Impedance Technique ◽  
Reinforced Cement ◽  
Coated Sand ◽  
Mechanical Strengths

Abstract Water and sand were used as the medium of multiwall carbon nanotube (MCNT) and prepared MCNT aqueous suspension and MCNT suspension-coated sand, respectively; afterwards, they were introduced into cement mortar (MNT/CM, MNTSM), respectively. Next, mechanical strengths and piezoresistive properties (DC resistivities (ρ v), AC impedances (Z r)) under cyclic loadings (σ c) of two types of MNT/CM and MNTSM nanocomposites were investigated to explore the intrinsic and self-sensing behaviors. Results reveal that MCNT can be evenly and well-coated on sand, which favors to achieve its intrinsic self-sensing property. Although the fraction changes in ρ v and Z r under the same σ c of MNTSM are both lower than those of MNT/CM, the stress sensitivity of MNTSM is only −1.16%/MPa (DC resistivity), −1.55%/MPa (AC impedance); its sensing linearity and stability (2.53, 2.45%; 2.73, 2.67%) are superior to those of MNT/CM (4.94, 2.57%; 3.78, 2.96%). Piezoresistivity using AC impedance technique is helpful to acquire balanced sensing sensitivity and stability while applied as intrinsic sensors in infrastructure.

scholarly journals Calcined Oyster Shell Powder as an Expansive Additive in Cement Mortar

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1322 ◽  
Author(s):  
Joon Ho Seo ◽  
Sol Moi Park ◽  
Beom Joo Yang ◽  
Jeong Gook Jang
Keyword(s):  
Compressive Strength ◽  
Cement Mortar ◽  
Autogenous Shrinkage ◽  
Oyster Shell ◽  
Heat Of Hydration ◽  
Strength Development ◽  
Flow Loss ◽  
Hardened Properties ◽  
Oyster Shell Powder ◽  
Shell Powder

The present study prepared calcined oyster shell powder having chemical composition and crystal structure of calcium oxide and lime, respectively, and investigated the fresh and hardened properties of cement mortar incorporating calcined oyster shell powder as an additive. The test results indicated that the hydration of calcined oyster shell powder promoted the additional formation of Ca(OH)2 at the initial reaction stage, thereby increasing the heat of hydration. In particular, the volumetric increase of calcined oyster shell powder during hydration compensated the autogenous shrinkage of mortar at early ages, ultimately leading to a clear difference in the shrinkage values at final readings. However, an excessive incorporation of calcined oyster shell powder affected the rate of C–S–H formation in the acceleratory period of hydration, resulting in a decrease in the compressive strength development. Meanwhile, the degree of flow loss was inconsequential and rapid flow loss was not observed in the specimens with calcined oyster shell powder. Therefore, considering the fresh and hardened properties of cement mortar, the incorporation of calcined oyster shell powder of approximately 3% by weight of cement is recommended to enhance the properties of cement mortar in terms of compressive strength and autogenous shrinkage.

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.

scholarly journals Mechanical Properties of Tin Slag Mortar

Recycling ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 42
Author(s):  
Nathaniel Olukotun ◽  
Abdul Rahman Mohd Sam ◽  
Nor Hassana Abdul Shukor Lim ◽  
Muyideen Abdulkareem ◽  
Isa Mallum ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Growth And Development ◽  
Cement Mortar ◽  
Sustainable Construction ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Hardened Properties ◽  
Tin Slag ◽  
Shape Characteristics ◽  
Better Than

The increased demand for cement mortar due to rapid infrastructural growth and development has led to an alarming depletion of fine aggregate. This has prompted the need for a more sustainable material as a total/partial replacement for natural fine aggregate. This study proposes the use of tin slag (TS) as a replacement for fine aggregate in concrete to bridge this sustainability gap. TS was used to replace fine aggregate at replacement levels of 0%, 25%, 50%, 75%, and 100% in cement mortar. Fresh and hardened properties of TS mortar were obtained. Flow tests showed that, as the TS quantity and the w/c ratio increased, the mortar flow increased. Similarly, the compressive strength increased as the TS replacement increased up to 50% replacement, after which a decline in strength was observed. However, with the TS replacement of fine aggregate up to 100%, a compressive strength of 6% above control was attained. The morphological features confirm that specimens with TS had a denser microstructure because of its shape characteristics (elongated, irregular, and rough), and, thus, plugged holes better than the control mortar. The natural sand’s contribution to strength was a result of better aggregate hardness as compared to TS. Hence, TS can be used as alternative for fine aggregate in sustainable construction.

Green Concrete made with Recycled Concrete Aggregates: Fresh and Hardened Properties

2018 ◽  
Author(s):  
Driton R. Kryeziu ◽  
Armend Muja ◽  
Fisnik Kadiu ◽  
Visar Krelani ◽  
Besian Sinani ◽  
...  
Keyword(s):  
Recycled Concrete ◽  
Green Concrete ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Hardened Properties
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