scholarly journals Hydration–Strength–Workability–Durability of Binary, Ternary, and Quaternary Composite Pastes

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 204
Author(s):  
Yi Han ◽  
Seokhoon Oh ◽  
Xiao-Yong Wang ◽  
Run-Sheng Lin
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Carbon Emissions ◽  
Cementitious Materials ◽  
Heat Of Hydration ◽  
Surface Resistivity ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Alternative Materials

At present, reducing carbon emissions is an urgent problem that needs to be solved in the cement industry. This study used three mineral admixtures materials: limestone powder (0–10%), metakaolin (0–15%), and fly ash (0–30%). Binary, ternary, and quaternary pastes were prepared, and the specimens’ workability, compressive strength, ultrasonic pulse speed, surface resistivity, and the heat of hydration were studied; X-ray diffraction and attenuated total reflection Fourier transform infrared tests were conducted. In addition, the influence of supplementary cementitious materials on the compressive strength and durability of the blended paste and the sustainable development of the quaternary-blended paste was analyzed. The experimental results are summarized as follows: (1) metakaolin can reduce the workability of cement paste; (2) the addition of alternative materials can promote cement hydration and help improve long-term compressive strength; (3) surface resistivity tests show that adding alternative materials can increase the value of surface resistivity; (4) the quaternary-blended paste can greatly reduce the accumulated heat of hydration; (5) increasing the amount of supplementary cementitious materials can effectively reduce carbon emissions compared with pure cement paste. In summary, the quaternary-blended paste has great advantages in terms of durability and sustainability and has good development prospects.

Use of Algerian Natural Mineral Deposit as Supplementary Cementitious Materials

2018 ◽  
Vol 34 ◽  
pp. 48-58 ◽  
Author(s):  
Karima Arroudj ◽  
Saida Dorbani ◽  
Mohamed Nadjib Oudjit ◽  
Arezki Tagnit-Hamou
Keyword(s):  
Mechanical Strength ◽  
Calcium Hydroxide ◽  
Cement Paste ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Heat Of Hydration ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Natural Mineral ◽  
Different Ages

Much of the current research on concrete engineering has been focused on including siliceous additions as supplementary cementitious materials (SCMs). Silica reacts with Calcium hydroxide release during cement hydration, and produces more C-S-H. The latter contributes to increase compactness, mechanical strengths and sustainability of concrete. This paper explores the hydration characteristics of cement paste based on various natural mineral additions, that are very abundant in Algeria and present a high silica content (ground natural pozzolana “PZ” and ground dune sand “DS”). For this purpose, several analyses were carried out on modified cement pastes and mortars. TheseSCMswere introduced by replacement levels of 15, 20 and 25 by weight of cement. We first, studied the effect of these SCMs on the heat of hydration and mechanical strength of mortars at different ages. The evolution of hydration of modified paste was studied, by using Thermal analysis (TG/TDA) at different ages, to analyze the Calcium Hydroxide (CH) content of the modified pastes. It is shown that the CH content of the mixes including SCMs is lower than that of the plain cement paste, indicating that silica reacts with the cement paste through a pozzolanic reaction. Increased pozzolanic activity results in higher amounts of Calcium Silicate Hydrate in the paste, which in turn results in higher compressive strength for modified cement mortars. Due to its crystalline morphology, the ground DS particles present a partial pozzolanic effect, compared to PZ which is semi-crystalline. Modified mortars by 20% DS can be the optimal composition. It presents satisfactory results: good mechanical strength and low heat of hydration. It can lead to an economic and sustainable concrete. Ground DS is very abounded in Africa and free of any impurities and can be a good alternativeSCMsin cement industry.

scholarly journals Study of Hydration and Microstructure of Mortar Containing Coral Sand Powder Blended with SCMs

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4248
Author(s):  
Xingxing Li ◽  
Ying Ma ◽  
Xiaodong Shen ◽  
Ya Zhong ◽  
Yuwei Li
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Silica Fume ◽  
Dilution Effect ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Chemical Effect ◽  
Granulated Blast Furnace Slag ◽  
Coral Sand

The utilization of coral waste is an economical way of using concrete in coastal and offshore constructions. Coral waste with more than 96% CaCO3 can be ground to fines and combined with supplementary cementitious materials (SCMs) such as fly ash, silica fume, granulated blast furnace slag in replacing Portland cement to promote the properties of cement concrete. The effects of coral sand powder (CSP) compared to limestone powder (LSP) blended with SCMs on hydration and microstructure of mortar were investigated. The result shows CSP has higher activity than LSP when participating in the chemical reaction. The chemical effect among CSP, SCMs, and ordinary Portland cement (OPC) results in the appearance of the third hydration peak, facilitating the production of carboaluminate. CSP-SCMs mortar has smaller interconnected pores on account of the porous character of CSP as well as the filler and chemical effect. The dilution effect of CSP leads to the reduction of compressive strength of OPC-CSP and OPC-CSP-SCMs mortars. The synergic effects of CSP with slag and silica fume facilitate the development of compressive strength and lead to a compacted isolation and transfer zone (ITZ) in mortar.

Suitability of Cordia millenii Ash Blended Cement in Concrete Production

2016 ◽  
Vol 22 ◽  
pp. 59-67 ◽  
Author(s):  
Olusola Emmanuel Babalola ◽  
Paul O. Awoyera
Keyword(s):  
Compressive Strength ◽  
Setting Time ◽  
Blended Cement ◽  
Cementitious Materials ◽  
Strength Properties ◽  
Supplementary Cementitious Materials ◽  
Sieve Analysis ◽  
Concrete Production ◽  
Alternative Materials ◽  
Concrete Control

Supplementary cementitious materials are most needed to enhance a sustainable development in poor communities. It is pertinent to investigate the suitability of such alternative materials for construction. The present study evaluates the strength characteristics of concrete made with varied proportion of Cordia millenii ash blended with Portland cement. Chemical composition of Cordia millenii and the setting time when blended with cement was determined. Other laboratory tests performed on Cordia millenii blended cement include: sieve analysis and specific gravity. Five replacement percentages of Cordia millenii (5%, 10%, 15%, and 20%) were blended with cement in concrete. Control specimens were also produced with only cement. Tests to determine the workability, air entrained, bulk density and compressive strength properties of the concrete were also conducted. Results obtained revealed that optimum Cordia millenii mix is 10%, which yielded the highest density and compressive strength in the concrete.

scholarly journals Characterization and Hydration Mechanism of Ammonia Soda Residue and Portland Cement Composite Cementitious Material

Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4794
Author(s):  
Dong Xu ◽  
Pingfeng Fu ◽  
Wen Ni ◽  
Qunhui Wang ◽  
Keqing Li
Keyword(s):  
Compressive Strength ◽  
Building Materials ◽  
Setting Time ◽  
Cement Composite ◽  
Cementitious Materials ◽  
Heat Of Hydration ◽  
Cementitious Material ◽  
Cement Industry ◽  
Hexagonal Plate ◽  
Hydration Mechanism

The use of ammonia soda residue (ASR) to prepare building materials is an effective way to dispose of ASR on a large scale, but this process suffers from a lack of data and theoretical basis. In this paper, a composite cementitious material was prepared using ASR and cement, and the hydration mechanism of cementitious materials with 5%, 10%, and 20% ASR was studied. The XRD and SEM results showed that the main hydration products of ASR-cement composite cementitious materials were an amorphous C-S-H gel, hexagonal plate-like Ca(OH)2 (CH), and regular hexagonal plate-like Friedel’s salt (FS). The addition of ASR increased the heat of hydration of the cementitious material, which increased upon increasing the ASR content. The addition of ASR also reduced the cumulative pore volume of the hardened paste, which displayed the optimal pore structure when the ASR content was 5%. In addition, ASR shortened the setting time compared with the cement group, and the final setting times of the pastes with 5%, 10%, and 20% ASR were 30 min, 45 min, and 70 min shorter, respectively. When the ASR content did not exceed 10%, the 3-day compressive strength of the mortar was significantly improved, but the 28-day compressive strength was worse. Finally, the hydration mechanism and potential applications of the cementitious material are discussed. The results of this paper promote the use of ASR in building materials to reduce CO2 emissions in the cement industry.

scholarly journals Effects of Adding Neutralized Red Mud on the Hydration Properties of Cement Paste

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4107
Author(s):  
Sukpyo Kang ◽  
Hyeju Kang ◽  
Byoungky Lee
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Red Mud ◽  
Aluminum Industry ◽  
Construction Material ◽  
Calorific Value ◽  
Cementitious Materials ◽  
Heat Of Hydration ◽  
Hydration Properties ◽  
The Aluminum Industry

Red mud is a highly alkaline waste by-product of the aluminum industry. Although recycling of red mud is being actively researched, a feasible technological solution has not been found yet. In this study, we propose that neutralization of red mud alkalinity could assist in its use as a construction material. Neutralized red mud (LRM + S; pH 6–8) was prepared by adding sulfuric acid to liquefied red mud (LRM; pH 10–12). After adding LRM and LRM + S to cement paste, the heat of hydration, compressive strength, and hydration products were examined. The experiments revealed that the calorific value of the cement paste with LRM was low, and its peak was delayed, when compared with that of plain cement paste (referred to as Plain), whereas the calorific value of the cement paste with LRM + S was similar to that of Plain. At the age of 28 d, the compressive strength of the cement paste with 10% LRM + S was 99% whereas that with 20% LRM was only 55% of the strength of Plain. Thus, our results help to resolve the issue of strength degradation of cementitious materials observed upon the addition of red mud and enable its reuse as a construction material.

scholarly journals Strength, Stiffness, and Microstructure of Wood-Ash Stabilized Marine Clay

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 796
Author(s):  
Abdullah Ekinci ◽  
Mohammad Hanafi ◽  
Ertug Aydin
Keyword(s):  
Compressive Strength ◽  
Carbon Emissions ◽  
Unconfined Compressive Strength ◽  
Ground Improvement ◽  
Cementitious Materials ◽  
Wood Ash ◽  
Pulse Velocity ◽  
Supplementary Cementitious Materials ◽  
Superior Performance ◽  
X Ray

The world’s population is growing at a rapid pace, thus increasing the need for shelter, which, because of increased carbon emissions, is making our planet less habitable. Thus, supplementary cementitious materials (SCMs) are used to reduce the embodied carbon emissions in the building sector. Wood-ash, as a replacement for cement in ground improvement, seems to be a promising material. In this study, we considered the strength, stiffness, and microstructural behavior of marine deposited clays of Cyprus treated with cement and wood-ash as a cement replacement. Since clay is abundant in nature, it could help stabilize waste to improve the mechanical behavior of produced composites. Portland cement (7%, 10%, and 13%) was replaced with various amount of wood-ash (5% and 10%) with two different dry densities (1400 and 1600 kg/m3) and three distinct curing periods (7, 28, and 60 days). Unconfined compressive strength (UCS), direct shear, porosity and pulse velocity tests were performed. Additionally, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy analysis (EDX) were performed for microstructural evaluation of clay–wood-ash–cement mixtures. The results revealed that the replacement of cement with 5% of wood-ash yielded superior performance. The microstructure investigation of wood-ash–cement–clay blends further showed the formation of a densified matrix with stable bonds. Furthermore, the porosity and strength properties (unconfined compressive strength, splitting tensile strength, cohesion (C) and friction angle (ϕ)) of blends have unique relationships with porosity and binder contents, which were further confirmed by other supplementary materials and soils.

Microstructure-Based Evolution of Compressive Strength of Blended Mortars: A Continuum Micromechanics Approach

2017 ◽  
Vol 1144 ◽  
pp. 121-127 ◽  
Author(s):  
Michal Hlobil
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Calcium Silicate ◽  
Multiscale Model ◽  
Elastic Stiffness ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Successful Model ◽  
Continuum Micromechanics ◽  
Calcium Silicate Hydrates

The evolution of stiffness and strength belong to the most important properties of mortars. Motivated by an increasing demand for clinker substitution by supplementary cementitious materials (SCMs), this paper presents a multiscale model for prediction of elastic stiffness and compressive strength of blended mortars. Mortars are envisioned as hierarchically organized materials with microstructural phases spanning several orders of magnitude. On the scale of hundreds of nanometers, "CSH foam" consists of amorphous calcium silicate hydrates mixed with capillary pores which on the scale of hundreds of microns acts as a contiguous matrix reinforced by unhydrated clinker, SCM grains, and by crystalline hydration products forming "cement paste". The largest scale of observation describes mortar as quartz sand aggregate inclusions embedded into a contiguous cement paste matrix. Continuum micromechanics homogenization approach is used to upscale stiffness from calcium silicate hydrates, represented by needle-shaped ellipsoids, up to the scale of mortar. Macroscopic quasi-brittle failure of mortar is associated with a concentration of strain energy density-related microscopic stresses within a critically oriented needle-shaped hydrate in "CSH foam". Successful model validation on OPC-based and blended mortars provides strong evidence that continuum micromechanics is an efficient tool for quantification of stiffness and compressive strength.

scholarly journals The Role of Supplementary Cementitious Materials (SCMs) in Ultra High Performance Concrete (UHPC): A Review

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1472
Author(s):  
Sungwoo Park ◽  
Siyu Wu ◽  
Zhichao Liu ◽  
Sukhoon Pyo
Keyword(s):  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Ultra High Performance Concrete ◽  
Environmental Aspect ◽  
Material Requirement ◽  
Strength And Durability

Although ultra high-performance concrete (UHPC) has great performance in strength and durability, it has a disadvantage in the environmental aspect; it contains a large amount of cement that is responsible for a high amount of CO2 emissions from UHPC. Supplementary cementitious materials (SCMs), industrial by-products or naturally occurring materials can help relieve the environmental burden by reducing the amount of cement in UHPC. This paper reviews the effect of SCMs on the properties of UHPC in the aspects of material properties and environmental impacts. It was found that various kinds of SCMs have been used in UHPC in the literature and they can be classified as slag, fly ash, limestone powder, metakaolin, and others. The effects of each SCM are discussed mainly on the early age compressive strength, the late age compressive strength, the workability, and the shrinkage of UHPC. It can be concluded that various forms of SCMs were successfully applied to UHPC possessing the material requirement of UHPC such as compressive strength. Finally, the analysis on the environmental impact of the UHPC mix designs with the SCMs is provided using embodied CO2 generated during the material production.

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