Combined effect of SCMs and curing temperature on mechanical properties of high-strength strain-hardening cementitious composites

2021 ◽  
pp. 073168442110517
Author(s):  
Hong-Joon Choi ◽  
Min-Jae Kim ◽  
Doo-Yeol Yoo
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
High Strength ◽  
Curing Temperature ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Multiple Cracks ◽  
Curing Conditions ◽  
Starting Point ◽  
Tensile Performance

This study was conducted to evaluate the curing temperature effect on the mechanical properties of high-strength strain-hardening cementitious composite (SHCC) containing waste supplementary cementitious materials (SCMs) and polyethylene (PE) fibers. High-strength SHCC is developed to extend the strain-hardening interval by simultaneously inducing multiple cracks and ensuring the durability and strength of high-strength concrete. The starting point of this study was to enhance the tensile performance and durability of high-strength SHCC by utilizing various SCMs. In addition, the optimal curing conditions were investigated to derive the maximum material potential of each SCM, which aims to advance the performance of high-strength SHCC. The temperatures employed for the curing process were 20, 40, and 90°C. Moreover, ground granulated blast-furnace slag (GGBS), silica fume (SF), and cement kiln dust (CKD), were used as a partial replacement for cement to determine the best mix for achieving optimal tensile performance. Four mix designs were prepared, including a plain test specimen composed entirely of cement as binder; therefore, a total of 12 types of specimens were set considering the three curing temperatures. A compressive strength test was conducted with cube specimens, and a direct tensile test was performed with dog-bone-shaped specimens. Derivative thermogravimetry (DTG) and energy dispersive X-ray spectroscopy (EDS) mapping were conducted to identify the microstructures. The SF-containing SHCC cured at 90°C exhibited the best tensile performance in terms of deformability and energy absorption capacity by achieving the highest strain capacity of 4.37% and g-value of 294.5 kJ/m3. In addition, the performance of each specimen was reconfirmed based on the DTG, EDS mapping, and crack pattern results. Through these results, the optimal SCM mixing amount and curing conditions that led to noticeable performance improvement of high-strength SHCC were identified.

Earth-Based Mortars: Mix Design, Mechanical Characterization and Environmental Performance Assessment

2022 ◽  
Author(s):  
Rayane de Lima Moura Paiva ◽  
Adriana Paiva Souza Martins ◽  
Lucas Rosse Caldas ◽  
Oscar A.M. Reales ◽  
Romildo Dias Toledo Filho
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Environmental Impacts ◽  
Calcium Chloride ◽  
Clay Fraction ◽  
Supplementary Cementitious Materials ◽  
Mix Design ◽  
Partial Replacement ◽  
Promising Alternative ◽  
The Earth

The incorporation of sustainable materials in the civil construction sector has grown in recent years to minimize environmental impacts. Among these materials, the use of earth, a local raw material that does not require much energy for its processing, appears as an advantageous and promising alternative. Earth mortars stabilized with natural binders, when compared to conventional mortars, can have technological, economic and environmental advantages. The objective of this work was to develop an earth-based mortar stabilized with mineral binders using a 1:3 binder to aggregate mass proportion, and to evaluate its fresh and hardened state properties, as well as its environmental impacts using Life Cycle Assessment (LCA) with a cradle to gate scope. The selected materials were divided in four groups: (i) cement, hydrated lime, fly ash and metakaolinite (binders), (ii) natural sand and coarse fraction of the earth (aggregates), (iii) calcium chloride and superplasticizer (additives) and (iv) water. In the matrix formulation the clay fraction from earth constituted the majority of the binder. The selection of supplementary cementitious materials as additional binders provided improvements in workability and mechanical properties of the mortar. A mix design was carried out using different cement (5; 7.5 and 10%) and fly ash (11; 13.5 and 16%) mass percentages. The water/binder material ratio, superplasticizer content and calcium chloride content were 0.65; 2% and 1%, respectively. The results showed that an increase in fly ash content combined with a decrease in cement content provided an increase in workability and a decrease in mechanical properties of mortars. Nevertheless, the mechanical performance of the mortars remained above the minimum values prescribed in Brazilian construction codes. From the results analysis it was concluded that partial replacement of cement by fly ash provided greater workability in the fresh state and reduced the environmental impacts of the earth-based mortar.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

2019 ◽  
Vol 292 ◽  
pp. 102-107 ◽  
Author(s):  
Josef Fládr ◽  
Petr Bílý ◽  
Karel Šeps ◽  
Roman Chylík ◽  
Vladimír Hrbek
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Water Content ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Depth Of Penetration ◽  
Cement Additive

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

scholarly journals Mechanical Properties of High-Volume Fly Ash Strain Hardening Cementitious Composite (HVFA-SHCC) for Structural Application

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2607 ◽  
Author(s):  
Chenhua Jin ◽  
Chang Wu ◽  
Chengcheng Feng ◽  
Qingfang Zhang ◽  
Ziheng Shangguan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Strain Hardening ◽  
Construction Material ◽  
High Volume ◽  
Partial Replacement ◽  
Cementitious Composite ◽  
Multiple Cracking ◽  
High Volume Fly Ash ◽  
Structural Applications

Strain-hardening cementitious composite (SHCC) is a kind of construction material that exhibits multiple cracking and strain-hardening behaviors. The partial replacement of cement with fly ash is beneficial to the formation of the tensile strain-hardening property of SHCC, the increase of environmental greenness, and the decrease of hydration heat, as well as the material cost. This study aimed to develop a sustainable construction material using a high dosage of fly ash (no less than 70% of the binder material by weight). Based on the micromechanics analysis and particle size distribution (PSD) optimization, six mixes with different fly ash to cement ratios (2.4–4.4) were designed. The mechanical properties of the developed high-volume fly ash SHCCs (HVFA-SHCCs) were investigated through tensile tests, compressive tests, and flexural tests. Test results showed that all specimens exhibited multiple cracking and strain-hardening behaviors under tension or bending, and the compressive strength of the designed mixes exceeded 30MPa at 28 days, which is suitable for structural applications. Fly ash proved to be beneficial in the improvement of tensile and flexural ductility, but an extremely high volume of fly ash can provide only limited improvement. The HVFA-SHCC mix FA3.2 (with fly ash to binder ratio of about 76% by weight) designed in this study is suggested for structural applications.

scholarly journals Effect of Curing Temperature Histories on the Compressive Strength Development of High-Strength Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Keun-Hyeok Yang ◽  
Jae-Sung Mun ◽  
Myung-Sug Cho
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
High Strength ◽  
Relative Strength ◽  
Curing Temperature ◽  
Strength Development ◽  
Curing Conditions ◽  
Strength Concrete ◽  
Equivalent Age ◽  
Compressive Strength Development

This study examined the relative strength-maturity relationship of high-strength concrete (HSC) specifically developed for nuclear facility structures while considering the economic efficiency and durability of the concrete. Two types of mixture proportions with water-to-binder ratios of 0.4 and 0.28 were tested under different temperature histories including (1) isothermal curing conditions of 5°C, 20°C, and 40°C and (2) terraced temperature histories of 20°C for an initial age of individual 1, 3, or 7 days and a constant temperature of 5°C for the subsequent ages. On the basis of the test results, the traditional maturity function of an equivalent age was modified to consider the offset maturity and the insignificance of subsequent curing temperature after an age of 3 days on later strength of concrete. To determine the key parameters in the maturity function, the setting behavior, apparent activation energy, and rate constant of the prepared mixtures were also measured. This study reveals that the compressive strength development of HSC cured at the reference temperature for an early age of 3 days is insignificantly affected by the subsequent curing temperature histories. The proposed maturity approach with the modified equivalent age accurately predicts the strength development of HSC.

Simulation of Mechanical Properties of Light-Burned Magnesium Oxide-Containing Concrete for Historical Dam Temperatures

2017 ◽  
Vol 744 ◽  
pp. 45-54
Author(s):  
Yong Min Yang ◽  
Zhao Heng Li ◽  
Tong Sheng Zhang ◽  
Qi Jun Yu
Keyword(s):  
Mechanical Properties ◽  
Body Temperature ◽  
Magnesium Oxide ◽  
Constant Temperature ◽  
Variable Temperature ◽  
Curing Temperature ◽  
Engineering Practice ◽  
Curing Conditions ◽  
Mgo Concrete ◽  
Curing Regime

Previous studies showed that curing regime has a significant influence on mechanical properties of light-burned magnesium oxide (MgO) concrete. However, research has been limited mostly to constant-temperature studies, whereas dams manufactured from concrete exist in variable-temperature environments. In order to achieve material performance parameters that agree more closely with engineering practice, the development of mechanical properties of light-burned MgO concrete curing at constant temperature and simulated dam body temperature was studied. The compressive strength, elastic modulus and ultimate tensile strain of light-burned MgO concrete increased with the increase of curing temperature, MgO content and curing age. These constant-temperature properties were similar to those under simulated dam body temperature curing conditions. A comparison of experimental results of simulated dam body temperature curing and constant temperature curing showed that a thermostatic curing system was suitable for calculating the laws of mechanics development for dam concrete.

scholarly journals Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs

2018 ◽  
Vol 199 ◽  
pp. 07006
Author(s):  
Md Shamsuddoha ◽  
Götz Hüsken ◽  
Wolfram Schmidt ◽  
Hans-Carsten Kühne ◽  
Matthias Baeßler
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Cementitious Materials ◽  
Strength Properties ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Hardened Cement ◽  
Binder Ratio ◽  
Strengthening Technique ◽  
Ultrafine Cement

Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced.

Macro, Micro and Nanoscale Bamboo Fiber as a Potential Reinforcement for Composites

2015 ◽  
Vol 668 ◽  
pp. 11-16 ◽  
Author(s):  
Viviane da Costa Correia ◽  
Fabíola Maria Siqueira ◽  
Rafael Donizetti Dias ◽  
Holmer Savastano
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
Bamboo Fiber ◽  
Partial Replacement ◽  
Synthetic Fibers ◽  
Chemical Pulping ◽  
Tropical Areas ◽  
Bamboo Fibers ◽  
Mechanical Nanofibrillation ◽  
Inorganic Matrices

Vegetal fibers are obtained from leaves, stalks, culms, fruit and seeds, and have been used in the macro, micro and nanoscale as partial replacement of synthetic fibers in organic and inorganic matrices. Bamboo has high strength fibers, and is one of main nonwood resources and is available in tropical areas worldwide. These characteristics justify the study and application of bamboo fiber as reinforcement in the macro, micro and nanoscale. The macrofibers were obtained from bamboo culms, the microfibers from the chemical pulping and the nanofibers were obtained from the mechanical nanofibrillation of the pulp. The fibers were subjected to chemical, physical, mechanical and morphological tests. There was modification in the chemical composition of the bamboo after pulping, such as decrease of amount of the lignin, hemicellulose and extractives in 42.4%, 33.3% and 83.7%, respectively.The bamboo fibers width have been reduced from 0.26 mm to 19.8 μm after pulping and after nanofibrillation process the width was reduced from 19.8 μm to 16.2 nm.The decrease of the fibers dimension can be seen from the micrographs and analyzing it mechanical properties, the bamboo fibers are a reinforcement potential in macro, micro and nanoscale to organic and inorganic matrices.

scholarly journals Strength and Microstructural Investigation of Quaternary Blended High-Strength Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ayele Bereda ◽  
Belachew Asteray
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
High Strength Concrete ◽  
Setting Time ◽  
Ceramic Powder ◽  
High Strength ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Microstructural Investigation ◽  
Strength Concrete

This research focuses on studying the effect of different supplementary cementitious materials (SCMs) such as waste ceramic powder (WCP), lime powder (LP), and ground granulated blast furnace slag (GGBS) in combination on strength characteristics and microstructure of quaternary blended high-strength concrete. To achieve the aims of the study, necessary physical and chemical composition tests were done for the raw materials. Then, mixes were designed into control mix with 100% Ordinary Portland Cement (OPC) and experimental mixes containing 30%, 40%, 50%, and 60% of GGBS, WCP, and LP in combination. Tests were conducted during casting and at curing ages of 7 and 28 days. Accordingly, the control mix which is concrete grade 50 (C-50) as per American Concrete Institute (ACI) mix design is used as a reference for comparison of test results with those specimens produced by partial replacement of SCMs. The characterizations of high-strength concrete are done using consistency, setting time, workability, compressive strength, flexural strength, and morphological tests. The optimum percentage replacement is 50% OPC replacement by 30% GGBS + 10% WCP + 10% LP. Based on the experimental investigations, the workability increases as the replacement level of SCMs increases from 30% to 60% by weight. Compressive strength and flexural strength results increase up to 11.41% and 20% when the percentage replacement increases from 30% to 50% of SCMs replacement at 28 days of curing time, respectively. There are also improvement in the microstructure and significant cost saving due to replacing OPC partially with SCMs with proportions mentioned above. Therefore, the practice of utilizing increased percentage of SCMs in quaternary blend in concrete can be beneficial for the construction industry and sustainability without compromising the quality of the concrete product.

Sign in / Sign up

Export Citation Format

Share Document