Analysis of Mortar Long-Term Strength with Supplementary Cementitious Materials Cured at Different Temperatures

2010 ◽  
Vol 107 (4) ◽  
Keyword(s):  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Term Strength ◽  
Different Temperatures

Long-term alkali-silica mitigation of high-alkali concrete with cement replacements

2021 ◽  
pp. 1-29
Author(s):  
Douglas Hooton ◽  
Benoit Fournier
Keyword(s):  
Cementitious Materials ◽  
Outdoor Exposure ◽  
Supplementary Cementitious Materials ◽  
Concrete Prism ◽  
Different Temperatures ◽  
Concrete Blocks ◽  
High Alkali ◽  
Mortar Bar ◽  
The Impact

The impact of high-alkali Portland cements on the prescribed level of supplementary cementitious materials required in the Canadian standard for akali-silica reaction mitigation was evaluated. Based on the results, for concretes containing aggregates exhibiting moderate reactivity, the maximum allowable cement alkali limit was raised from 1.00% to 1.15%. For all levels of aggregate reactivity, cement alkali contents could be allowed up to 1.25% provided the recommended level of mitigation by supplementary cementitious materials was increased. In the initial laboratory study, mortar bars and concrete prisms were cast and monitored using two different reactive aggregates and recommended levels of fly ash and slag. For the concrete prism tests, the alkali contents of the cements were increased to 1.25%, as per the standard, or were increased by 0.25%. Instrumented outdoor exposure concrete blocks, along with additional concrete prisms stored at different temperatures, were cast from numerous mixtures made with cement alkali equivalents ranging up to 1.22%. This paper report on the long-term performance of the prisms and concrete blocks after 12 and 27 years. The performance of the outdoor blocks is also compared to predicted performance based on the accelerated mortar bar and concrete prism test results.

scholarly journals Long-term mechanical and shrinkage properties of cementitious grouts for structural repair

2019 ◽  
Vol 4 ◽  
pp. 9-15
Author(s):  
Md Shamsuddoha ◽  
Götz Hüsken ◽  
Wolfram Schmidt ◽  
Hans-Carsten Kühne ◽  
Matthias Baeßler
Keyword(s):  
Fly Ash ◽  
Flexural Strength ◽  
Cementitious Materials ◽  
Response Surfaces ◽  
Supplementary Cementitious Materials ◽  
Strength Development ◽  
Structural Repair ◽  
Positive Effects ◽  
Micro Silica

Grouts have numerous applications in construction industry such as joint sealing, structural repair, and connections in precast elements. They are particularly favoured in rehabilitation of structures due to penetrability and convenience of application. Grouts for repair applications typically require high-performance properties such as rapid strength development and superior shrinkage characteristics. Sometimes industrial by-products referred as supplementary cementitious materials (SCM) are used with neat cement due to their capabilities to provide binding properties at delayed stage. Micro silica, fly ash and metakaolin are such SCMs, those can modify and improve properties of cement products. This study aims at investigating long-term mass loss and linear shrinkage along with long-term compressive and flexural strength for grouts produced from ultrafine cement and SCMs. A series of mixtures were formulated to observe the effect of SCMs on these grout properties. Properties were determined after 365 days of curing at 23oC and 55% relative humidity. The effect of SCMs on the properties are characterised by statistical models. Response surfaces were constructed to quantify these properties in relation to SCMs replacement. The results suggested that shrinkage was reduced by metakaolin, while micro silica and fly ash had positive effects on compressive and flexural strength, respectively.

Pozzolanic Reaction of Supplementary Cementitious Materials and Its Effects on the Strength of Mass Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 505-511 ◽  
Author(s):  
Hua Shan Yang ◽  
Kun He Fang ◽  
Sheng Jin Tu
Keyword(s):  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
Supplementary Cementitious Materials ◽  
Mass Concrete ◽  
X Ray Diffraction ◽  
X Ray ◽  
Slag Powder ◽  
Phosphorous Slag ◽  
Better Than

The present study aims to investigate the opportunity to largely substitute low heat Portland cement of mass concrete with supplementary cementitious materials. The pozzolanic reaction of two types of supplementary cementitious materials, phosphorous slag powder and fly ash , were determined by X-ray diffraction, differential thermal analysis–thermogravimetry and scanning electron microscopy from 28 to 90 days. The properties of mortar and mass concrete containing 30% of supplementary cementitious materials were also investigated. Results showed that supplementary cementitious materials could decrease the amount of calcium hydroxide, fill the capillary pores, thus making the mortar and mass concrete more compact and durable. Long-term strength of mass concrete containing 30% of supplementary cementitious materials were comparable (or even better) than the control concrete (without supplementary cementitious materials) at constant workability, while the Young’s modulus was lower than the control concrete.

Effect of Red Mud on Mechanical Properties of Loess–Containing Aluminosilicate Based Cementitious Materials

2009 ◽  
Vol 610-613 ◽  
pp. 155-160
Author(s):  
Jian Hua Wan ◽  
Heng Hu Sun ◽  
Ying Ying Wang ◽  
Chao Li
Keyword(s):  
Mechanical Properties ◽  
Red Mud ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
The Other ◽  
Term Strength ◽  
Other Hand ◽  
Early Strength ◽  
The One

The effect of the thermal treated red mud on mechanical properties of loess –containing aluminosilicate based cementitious materials is investigated. And the characteristic of hydration production is tested using XRD, SEM and EDAX methods. The results show that the thermal treated red mud not only has excellent cementitious properties but also can improve the mechanical properties of loess –containing aluminosilicate based cementitious materials. Moreover when the content of red mud is 5%, the improved effect is optimal. On the one hand, the alkaline ingredients of red mud can promote abundant ettringites to produce at early ages. And the ettringites contribute to early strength of the cementitious material. On the other hand, the content of red mud is too high to improve the long-term strength.

scholarly journals Use of supplementary cementitious materials (SCMs) in reinforced concrete systems – Benefits and limitations

2020 ◽  
Vol 10 (2) ◽  
pp. 147-164
Author(s):  
Radhakrishna G. Pillai ◽  
Ravindra Gettu ◽  
Manu Santhanam
Keyword(s):  
Drying Shrinkage ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Chloride Ingress ◽  
Shrinkage Cracking ◽  
Carbonation Resistance ◽  
Chloride Attack ◽  
Cementitious Systems

About a decade of research carried out at IIT Madras on cementitious systems has shown that the partial replacement of portland cement with supplementary cementitious materials (SCMs) has benefits as well as limitations. The SCMs do not adversely affect the long-term compressive strength and drying shrinkage of concretes, though there may be some compromise in workability and the resistance against plastic shrinkage cracking. Through the assessment of the chloride ingress rate in concrete and chloride threshold of steel, it is evident that the use of SCMs could significantly enhance the service life under chloride attack, though there is a reduction of the carbonation resistance. More importantly, SCMs can lead to significant reduction of the carbon footprint of concrete, and hence, are essential to achieve sustainability.

scholarly journals Durability of mortars modified by the effect of combining SPA polymers and supplementary cementitious materials

2018 ◽  
Vol 149 ◽  
pp. 01091 ◽  
Author(s):  
B. Belbachir ◽  
A.S. Benosman ◽  
H. TaÏbi ◽  
M. Mouli ◽  
Y. Senhadji ◽  
...  
Keyword(s):  
Building Materials ◽  
Low Cost ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Acid Attack ◽  
Repair Materials ◽  
Mineral Additions ◽  
Repair Mortars ◽  
Different Levels

Nowadays, the major concern of professionals in the field of building materials is to improve the properties induced by the addition of different additives (polymers) and mineral additions (Supplementary Cement Materials SCMs) and to eventually adapt them to a particular application. This race towards performance has resulted in mortar formulations that are increasingly complex and rich in diversified additions. This is an industry-friendly practice since it generally yields a mortar modified by the combination of a polymer and SCMs, at low cost and low environmental impact, with an improved sustainability in the long term. In order to improve the durability of SCM-modified repair mortars, it seemed interesting to evaluate the influence of adding the styrene polyacrylic (SPA) Latex on the properties of these mortars when exposed to aggressive media such as acids. Composite mortars based on pozzolanic mineral additions, containing different levels of 0.5%, 1% and 2%w latex, were stored in acid solutions, for various periods of immersion. The analysis of the microstructure of these mortars, after exposure to acid attack, was carried out by FTIR spectroscopy. The results obtained allowed to demonstrate the beneficial effect of adding the SPA polymer and the pozzolanic additions to the modified materials and to show their improved resistance to acid attacks, such as HNO3 and H3PO4 solutions at 8%. The best durability properties of the mortars modified by the combination of the polymer and the additional cementitious materials observed in this study indicate a longer service life of the repaired structure when using this type of Latex-modified repair materials.

scholarly journals Assessment of Rational Design of Self-Compacting Concrete Incorporating Fly Ash and Limestone Powder in Terms of Long-Term Durability

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2863
Author(s):  
Pavel Reiterman ◽  
Roman Jaskulski ◽  
Wojciech Kubissa ◽  
Ondřej Holčapek ◽  
Martin Keppert
Keyword(s):  
Fly Ash ◽  
Rational Design ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Limestone Powder ◽  
Experimental Program ◽  
Initial Surface ◽  
Freeze Thaw ◽  
Mineral Additive

Self-compaction concrete (SCC) is ranked among the main technological innovations of the last decades. Hence, it introduces a suitable possibility for further utilization of supplementary cementitious materials (SCM) in terms of sustainable development. The aim of the work is the assessment of a new approach to binder design, which takes into consideration the activity of the used mineral additive. The proposed approach, which allows a systematic design of a binding system with varied properties of the used mineral additive, was studied on ternary blends consisting of Portland cement (PC), limestone powder and fly ash (FA). The verification was conducted on SCC mixtures in terms of their workability, mechanical properties and the most attention was paid to long-term durability. The long-term durability was assessed on the basis of shrinkage measurement, freeze-thaw resistance and permeability tests including initial surface absorption, chloride migration, water penetration and an accelerated carbonation test, which was compared with the evolution of carbonation front in normal conditions. The durability of studied mixtures was evaluated by using durability loss index, which allow general assessment on the basis of multiple parameters. The carbonation resistance had a dominant importance on the final durability performance of studied mixtures. The experimental program revealed that the proposed design method is reliable only in terms of properties in fresh state and mechanical performance, which were similar with control mixture. Despite suitable results of freeze-thaw resistance and shrinkage, an increasing amount of fly ash in terms of the new design concept led to a fundamental increase of permeability and thus to decay of long-term durability. Acceptable properties were achieved for the lowest dosage of fly ash.

scholarly journals Supplementary Cementitious Materials for Concrete: Characterization Needs

2012 ◽  
Vol 1488 ◽  
Author(s):  
Maria Juenger ◽  
John L. Provis ◽  
Jan Elsen ◽  
Winnie Matthes ◽  
R. Doug Hooton ◽  
...  
Keyword(s):  
Standardized Test ◽  
Mechanical Performance ◽  
Cementitious Materials ◽  
Test Methods ◽  
Supplementary Cementitious Materials ◽  
Characterization Methods ◽  
Granulated Blast Furnace Slag ◽  
Concrete Characterization ◽  
Furnace Slag

ABSTRACTA wide variety of materials are currently used as supplementary cementitious materials (SCMs) for concrete, including natural materials and byproducts from various industries. Historically, natural SCMs, mostly derived from volcanic deposits, were common in concrete. In recent years, the dominant SCMs have been industrial by-products such as fly ash, ground granulated blast furnace slag (GGBFS), and silica fume. There is currently a resurgence of research into historic and natural SCMs, as well as other alternative SCMs for many reasons. The primary benefits of SCM use in improvement of long-term mechanical performance, durability, and sustainability are widely accepted, so local demand for these materials can exceed supply. This paper describes some of the SCMs that are attracting attention in the global research community and the properties and characteristics of these materials that affect their performance. Special attention is paid to the importance and demands of material characterization. Many SCMs do not necessarily lend themselves to characterization methods used in standardized test methods, which sometimes fail to describe the properties that are most important in predicting reactivity.

scholarly journals Estimating CO2 Emission Savings from Ultrahigh Performance Concrete: A System Dynamics Approach

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 995
Author(s):  
Mubashar Sheheryar ◽  
Rashid Rehan ◽  
Moncef L. Nehdi
Keyword(s):  
System Dynamics ◽  
Co2 Emissions ◽  
New Technologies ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Civil Infrastructure ◽  
Portland Cement Concrete ◽  
Flexible Framework ◽  
Cement And Concrete

Ordinary Portland cement concrete (OPC) is the world’s most consumed commodity after water. However, the production of cement is a major contributor to global anthropogenic CO2 emissions. In recent years, ultrahigh performance concrete (UHPC) has emerged as a strong contender to replace OPC in diverse applications. UHPC has much higher mechanical strength, and thus less material is used in a structural member to resist the same load. Moreover, it has a much longer service life, reducing the long-term need for repair and replacement of aging civil infrastructure. Thus, UHPC can enhance the sustainability of cement and concrete. However, there is currently no robust tool to estimate the sustainability benefits of UHPC. This task is challenging considering that such benefits can only be captured over the long-term since variables, such as population growth and cement demand per capita, become more uncertain. In addition, the problem of CO2 emissions from cement and concrete is a complex system affected by time-dependent feedback. The System Dynamics (SD) method has specifically been developed for modeling such complex systems. Accordingly, a SD model was developed in this study to test various pertinent policy scenarios. It is shown that UHPC can reduce cumulative CO2 emissions of cement and concrete—over the studied simulation period—by more than 17%. If supplementary cementitious materials are further deployed in UHPC and new technologies permit reducing the carbon footprint per unit mass of cement, emission savings can become more substantial. The model offers a flexible framework where the user controls various inputs and can extend the model to account for new data, without the need for reconstruction of the entire model.

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