Characterization and comparison of the cement produced using clam wreckage and limestone: Cement clinker, freeze–thaw resistance, and hydration products

2021 ◽  
Vol 310 ◽  
pp. 125219
Author(s):  
Qiang Wang ◽  
Qing Lu ◽  
Xiaochang Li ◽  
Zhiming Wang ◽  
Xianjun Lyu
Keyword(s):  
Cement Clinker ◽  
Hydration Products ◽  
Freeze Thaw ◽  
Limestone Cement

The Effect on Cement Mortar and Concrete by Admixture of Spray Drying Absorption Products

1989 ◽  
Vol 178 ◽  
Author(s):  
Kirsten G. Jeppesen
Keyword(s):  
Grain Size ◽  
Fly Ash ◽  
Cement Mortar ◽  
Setting Time ◽  
Mineralogical Composition ◽  
Cement Clinker ◽  
Strength Development ◽  
Fall Meeting ◽  
Freeze Thaw ◽  
Spray Dried

AbstractSpray dried absorption products (SDA) having special characteristics are used as substitutes for cement in the preparation of mortars; the qualities of the resulting mixed mortars are described. Conditions are described for mortar mixes, data for which were presented at the MRS Fall Meeting 1987.The influence of the composition of the SDA on water requirement and setting time has been studied. A full scale project involving 3 precast, reinforced concrete front-elements containing 20 and 30 wt.% SDA is described. Strength development, mineralogical composition and corrosion were monitored for two years.A non-standard freeze-thaw experiment was performed which compares mortars containing SDA and fly ash (FA) and also shows the effect of superplasticizer.The possibility of improving the SDA by grinding has been tested and a limited improvement has been found. The strength of the mixed mortars seems slightly influenced by the grain size of SDAGypsum (CaSO4·2H2O), synthetic calcium-sulphite (CaSO3·½H2O) and 2 SDAs have been used as retarders for cement clinker. Mortar test prisms have been cast and comparative strengths after curing for 3 years are reported

Nano Titania Reinforced Limestone Cement: Physico-Mechanical Investgation

2018 ◽  
Vol 786 ◽  
pp. 248-257
Author(s):  
Mohmoud A. Abuelseoud ◽  
Asmaa S. Hamouda ◽  
Ibrahim M. Ismail ◽  
M.A. El-Sheikh
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Hydraulic Properties ◽  
Water Retention ◽  
Physical And Mechanical Properties ◽  
Sem Analysis ◽  
Cement Clinker ◽  
Titanium Silicate ◽  
Cement Pastes ◽  
Limestone Cement

Studying physical and mechanical properties of limestone cement pastes blended by TiO2 nanoparticles (i.e., particle size less than 100 nm). Three mixes are prepared for this study (5.00, 10.00 and 25.00 wt. % of limestone) partially replaced cement/clinker by TiO2 nanoparticles. Fillers are carefully selected which reinforcing cement workability or water retention they could be inert or have slightly hydraulic properties. Limestone is most common filler that fills the pores between cement particles due to the formation of monocarboaluminate, while nanoparticles increase the hydration C-S-H gel product and calcium titanium silicate which hardened the cement pastes. Nanoparticles show a great effect in reinforcing the mechanical strength of cement pastes due to the fact that TiO2-nanoparticles act as active nuclei site forming C-S-H gel observed as honeycomb-like plus improving cement to water demined (W/C) ratio. SEM analysis proves that the morphology of cement structure is well arranged and compacted.

Aging Mechanism of Dam Concrete under the Action of Freeze-Thaw Damage

2014 ◽  
Vol 584-586 ◽  
pp. 2121-2124
Author(s):  
Yan Shi ◽  
Hua Quan Yang ◽  
Xiang Li ◽  
Jia Zheng Li
Keyword(s):  
Weight Loss ◽  
Elastic Modulus ◽  
Concrete Structure ◽  
Loss Rate ◽  
Hydration Products ◽  
Weight Loss Rate ◽  
Freeze Thaw ◽  
Aging Mechanism ◽  
Dam Concrete ◽  
Air Entrained Concrete

Aging mechanism of dam concrete under the action of freeze-thaw damage was analyzed by testing macro and micro performance. The results show that compressive, splitting tensile and flexural strengths reached 58.4%, 61.3% and 57.8% of the initial values after 150 cycles. Strength is the most sensitive indicator of freeze-thaw damage, followed by weight loss rate, relative dynamic elastic modulus and ultrasonic velocity. After freeze-thaw damage, concrete structure becomes loose, porous amount gradually increased and pore size especially over 25nm expanded. Microcracks not only exist in the hydration products, but also destroy the bubbles structure in air entrained concrete, which is the main cause of freeze-thaw damage.

High Durability Glass-Fiber Reinforced Modified Cementitious Matrix

1990 ◽  
Vol 211 ◽  
Author(s):  
J. Thiery ◽  
A. Vautrin ◽  
J. Francois-Brazier
Keyword(s):  
Dominant Role ◽  
Ultimate Strain ◽  
Accelerated Ageing ◽  
Hydration Products ◽  
Acrylic Polymers ◽  
Freeze Thaw ◽  
Glass Fiber Reinforced ◽  
High Durability ◽  
The Matrix

AbstractIn AR-GFRC growth of hydration products around the filaments plays a dominant role in inducing embrittlement of the fibers and loss of toughness of the composites.The purpose of this paper is to present the way to limit the anchorage of the fibers in the matrix and to obtain a long term flexural strength of 30 MPa and an ultimate strain of 0,7 %. The improvement of the matrix is obtained by using selected metakaolinites and acrylic polymers in order to optimize the nature of the hydrates in the interface between the fibers and the matrix.The mecanical properties and durability behaviours are reviewed using three accelerated ageing tests based on warm water, wet-dry cycles and freeze-thaw cycles. The toughness indices proposed by Shah, Ludirdja and Daniel [12] are calculated, pointing out the improvements of toughness and durability of the new V~trotex-Saint-Gobain AR-GFRC system.

Hydration and hydration products of two-phase Portland cement clinker doped with Na2O

2007 ◽  
Vol 19 (3) ◽  
pp. 125-131 ◽  
Author(s):  
S. Wistuba ◽  
D. Stephan ◽  
G. Raudaschl-Sieber ◽  
J. Plank
Keyword(s):  
Portland Cement ◽  
Cement Clinker ◽  
Hydration Products ◽  
Two Phase ◽  
Portland Cement Clinker

Lowering the Carbon Footprint of Concrete by Reducing Clinker Content of Cement

2012 ◽  
Vol 2290 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Michael Thomas ◽  
Laurent Barcelo ◽  
Bruce Blair ◽  
Kevin Cail ◽  
Anik Delagrave ◽  
...  
Keyword(s):  
Portland Cement ◽  
Alternative Fuels ◽  
Blended Cement ◽  
Concrete Pavement ◽  
Cement Clinker ◽  
Portland Limestone Cement ◽  
Wide Range ◽  
Limestone Cement ◽  
Reduce Carbon Dioxide ◽  
Cementing Material

Significant efforts have been made to reduce carbon dioxide (CO2) emissions associated with the manufacture of portland cement, primarily by making the process more energy efficient and increasing the use of alternative fuels. Further reductions in CO2 can be achieved by lowering the clinker component of the cement because the pyroprocessing used to manufacture clinker produces approximately 1 tonne of CO2 for every tonne of clinker. Traditionally reductions in the clinker content of cement have been achieved by producing blended cement consisting of portland cement combined with a supplementary cementing material (SCM). In Canada, it is now permitted to intergrind up to 15% limestone with cement clinker to produce portland limestone cement or blended portland limestone cement. Recent trials were conducted at the Brookfield cement plant in Nova Scotia to evaluate the performance of a blended cement containing 15% ground, granulated blast furnace slag (an SCM) with that of a blended portland limestone cement containing the same amount of slag plus 12% interground limestone. Performance was evaluated by the construction of a section of concrete pavement using concrete mixtures produced with the two cements and various amounts of fly ash (another SCM). A wide range of laboratory tests were performed on the concrete specimens cast on site during the placement of the concrete pavement. The results indicated that the cements were of equivalent performance.

scholarly journals Comparative study on mechanisms for improving mechanical properties and microstructure of cement paste modified by different types of nanomaterials

2021 ◽  
Vol 10 (1) ◽  
pp. 370-384
Author(s):  
Tao Meng ◽  
Kanjun Ying ◽  
Xiufen Yang ◽  
Yongpeng Hong
Keyword(s):  
Mechanical Properties ◽  
Cement Paste ◽  
Cement Hydration ◽  
Inhibitory Effect ◽  
Test Methods ◽  
Cement Clinker ◽  
Hydration Products ◽  
Nucleation Effect ◽  
Nano Graphene ◽  
Nano Titanium Dioxide

Abstract Filling and nucleation are the mechanisms of modifying cement paste with nanomaterials, as investigated by previous studies, and are difficult to reflect the different effects of nanomaterials, especially on the changes of cement clinker and hydration products in the cement hydration process. In this study, the mechanisms of modifying cement paste with nano-calcium carbonate (NC), nano-graphene oxide (NG), nano-silica (NS), and nano-titanium dioxide (NT) were investigated by determining the mechanical properties of cement paste treated with nanomaterials and analysing the changes in the cement clinker (tricalcium silicate and dicalcium silicate), hydration products (portlandite and ettringite), and microstructure through many micro-test methods. The results indicate that the incorporation of nanomaterials could improve the early strength of cement paste specimens due to more consumption of cement clinker. Meanwhile, different nanomaterials promote the formation of different hydration products at early ages. C–A–S–H gel, flower-like ettringite, and C–S–H seeds are widely distributed in the cement paste with the incorporation of NC, NG, and NS, respectively. NT exhibits insignificant nucleation effect and has inhibitory effect on portlandite precipitation. This study provides key insights into the mechanism of nanomaterials from the perspective of cement hydration, which may promote the further research and application of nanomaterials in the cement and concrete industries.

scholarly journals Aggressive Environment Resistance of Concrete Products Modified With Nano Alumina and Nano Silica

2021 ◽  
Vol 8 ◽  
Author(s):  
Yao Zhao ◽  
Na Cui ◽  
Shuyuan Zhao ◽  
Yunzhe Zhu ◽  
Pengkun Hou ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Dynamic Modulus ◽  
Hydration Products ◽  
Nano Silica ◽  
Environmental Resistance ◽  
Freeze Thaw ◽  
Aggressive Environment ◽  
The Past ◽  
Nano Alumina ◽  
Durability Of Concrete

The service life of concrete products with exposure to an aggressive environment has raised great concerns in the past decades. Nanomaterials have been used as a promising approach to improve the environmental resistance of concrete products when exposed to synergistic attacks. The impacts of CaCl2 on nano-modified concrete, especially along with freeze/thaw (F/T) and wet/dry (W/D) cycles, were barely discussed. In this study, the impacts of CaCl2 along with F/T and W/D cycles on the nano SiO2 and Al2O3 modified concrete were investigated. The mass loss, flexural strength, compressive strength, and relative dynamic modulus of elasticity were tested to evaluate the durability of concrete products. The testing results indicate that the addition of nanoparticles has a distinctive effect on the environment resistance enhancement of concrete samples. The microstructure analysis demonstrates that with the addition of nanoparticles, high-density hydration products were formed, which is beneficial to the properties enhancement of concrete products. This study not only provides an approach to realize the nano modification on the durability of concrete products but also helps to design and fabricate environmentally resistant concrete products when exposed to a synergistic aggressive environment.

scholarly journals Using Alkali-Activated Cementitious Materials to Solidify High Organic Matter Content Dredged Sludge as Roadbed Material

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Zhong Gu ◽  
Sudong Hua ◽  
Weixing Zhao ◽  
Sisheng Li ◽  
Zhen Gao ◽  
...  
Keyword(s):  
Organic Matter ◽  
Organic Matter Content ◽  
Matter Content ◽  
Hydration Products ◽  
Volume Stability ◽  
Freeze Thaw ◽  
High Organic Matter Content ◽  
Stability Performance ◽  
High Organic Matter ◽  
Dredged Sludge

It is difficult to treat dredged sludge with high organic matter content by solidification. A new solidification of dredged sludge with high organic matter content was developed, using cement, fly ash, slag, and phosphogypsum as a solidifier and strong oxidant KMnO4and GH as additives, to improve the engineering performance of dredged sludge and make it as a roadbed material possible. The properties of the solidified samples were determined in terms of unconfined compressive strength, products of hydration, toxicity characteristics, water stability, freeze-thaw resistance, and volume stability. The microstructure and hydration products of the dredged sludge after solidification were evaluated by X-ray diffraction analysis, scanning electron microscopy, and thermogravimetry-differential scanning calorimetry analysis. Experimental results showed that the strength of the solidified samples has been significantly improved after treatment by strong oxidants. The effect of GH is better than that of KMnO4. Hydration products (ettringite) were well formed. After solidification by using the binders and strong oxidant GH, the samples had sufficient strength and good water stability performance, freeze-thaw resistance performance, and volume stability performance. The leach liquid of the dredged sludge solidified body meets the standard requirements. So, the dredged sludge after solidification can reach the requirement of the roadbed material.

scholarly journals Influence of Alternation of Sulfate Attack and Freeze-Thaw on Microstructure of Concrete

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Huaquan Yang ◽  
Xiaoming Shen ◽  
Meijuan Rao ◽  
Xiang Li ◽  
Xiaodong Wang
Keyword(s):  
Water Absorption ◽  
Absorption Rate ◽  
Concrete Strength ◽  
Test Methods ◽  
Sulfate Attack ◽  
Absorption Method ◽  
Hydration Products ◽  
Freeze Thaw ◽  
Effective Factor ◽  
Air Void

The effects of sulfate attack and freeze-thaw alternation on the concrete microstructure were systemically investigated by advanced test methods such as water absorption method, air void analysis, XRD, and SEM. The experimental results indicated that freeze-thaw damage is the major effective factor in the sulfate attack and freeze-thaw alternation test. In the alternation test, average aperture of capillary pores of specimens was smaller, pores uniformity was better, and water absorption rate was lower than those specimens used in the single freeze-thaw damage test. The average aperture and uniformity of pores could be improved by adding fly ash and slag. Damage was accumulated in many cycles of freeze-thaw and microcracks increased during the test. At the same time, the hydration products of the concrete developed into expansive gypsum, AFt, and TSA without any strength during sulfate attack. The results of the microstructure analysis form XRD and SEM are in accordance with that of AFt, about 3 μm length, around which other hydration products decomposed by C-S-H after sulfate attack resulted in loss of concrete strength.

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