Rheological properties, compressive strength, hydration products and microstructure of seawater-mixed cement pastes

2020 ◽  
Vol 114 ◽  
pp. 103770 ◽  
Author(s):  
Junjie Wang ◽  
Jianhe Xie ◽  
Yuli Wang ◽  
Yongliang Liu ◽  
Yahong Ding
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Hydration Products ◽  
Cement Pastes

scholarly journals Analysis of the Effect of Various Types of Limestone as a Main Constituent of Cement on the Chosen Properties of Cement Pastes and Mortars

2019 ◽  
Vol 65 (3) ◽  
pp. 75-86
Author(s):  
J. Gołaszewski ◽  
G. Cygan ◽  
M. Gołaszewska
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Yield Stress ◽  
Drying Shrinkage ◽  
Plastic Viscosity ◽  
Main Constituent ◽  
Cement Pastes ◽  
Mortar Strength ◽  
The Impact

AbstractThe article is an attempt to compare the impact of the use of various types of limestone as the main constituent of cement on selected mortar properties. Four different limestones were added in amount of 15, 30, 40% to CEM I 42.5 R to obtain limestone cemens. Rheological properties (yield stress, plastic viscosity) of fresh mortar, tensile and compressive mortar strength, early shrinkage, and drying shrinkage were tested. Obtained results indicate that both tensile and compressive strength decreases with the increase of the limestone content in cement. Limestone can worsen or improve workability, depending on distribution of limestone grains. The addition of limestone increases the early shrinkage, but reduces the shrinkage after 28 days. Studies show that the granulation of limestone plays an important role in determining the influence of limestone on mortar properties.

Preparation and Mechanical Performance of Supplementary Cementing Materials Cementitious by Electroplating Sludge

2020 ◽  
Vol 837 ◽  
pp. 133-138
Author(s):  
Chang Sen Zhang ◽  
Xue Su Gu ◽  
Jie Gao ◽  
Yu Yang ◽  
Bao Gui Zhu
Keyword(s):  
Heavy Metals ◽  
Compressive Strength ◽  
Calcium Hydroxide ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Steel Slag ◽  
Hydration Products ◽  
Cement Pastes ◽  
Supplementary Cementing Materials ◽  
Electroplating Sludge

Preparation, microstructure and mechanical performance of novel supplementary cementing materials prepared with electroplating sludge and steel slag as raw materials were studied. It was found that the electroplating sludge could be mixed with steel slag at appropriate ratios to make SCMs that posse certain compressive strength. The results shows that the supplementary cementing materials prepared in this article can increase the compressive strengths of cement when it substitutes for cement in appropriate proportion. The microstructure and hydration products of cement with SCMs were examined by XRD and SEM. The results indicated that the content of calcium hydroxide formed in paste significantly reduced and Aft increased, as the content of the supplementary cementing materials increased. In addition, the heavy metals elements in the electroplating sludge could be effective cured in cement pastes and reduced the pollution to the environment.

Investigation of Composite Deflocculant Influence on the Properties of the Refractory Castable with Chamotte Aggregate

2014 ◽  
Vol 682 ◽  
pp. 256-260 ◽  
Author(s):  
Ina Pundienė ◽  
Irina Demidova-Buiziniene ◽  
A. Volochko
Keyword(s):  
Compressive Strength ◽  
Rheological Properties ◽  
Comparative Studies ◽  
Sodium Tripolyphosphate ◽  
Strength Properties ◽  
Cement Matrix ◽  
Hydration Products ◽  
Drying Process ◽  
Different Types ◽  
Compressive Strength Of Concrete

The influence of different types of deflocculants, PCE and sodium tripolyphosphate, on the rheological properties of the cement matrix was studied. It was established that composite deflocculant consisting of sodium tripolyphosphate and PCE Castament FS 20 provides the best rheological properties of the cement matrix and affects the composition of the hydration products. During the drying process of matrix with composite deflocculants mineral stratlingite additionally formed, which contributes to increment of strength properties. Comparative studies of refractory castable strength properties with chamotte aggregate showed that the compressive strength of concrete samples with composite deflocculants after hardening and after drying and burning is almost two times higher than the strength of samples with separate deflocculants.

scholarly journals DISTRIBUTION OF HYDRATION PRODUCTS IN THE MICROSTRUCTURE OF CEMENT PASTES

2020 ◽  
Vol 27 ◽  
pp. 84-89
Author(s):  
Michal Hlobil
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Numerical Study ◽  
Hardened Cement ◽  
Spatial Gradient ◽  
Hydration Products ◽  
Hardened Cement Paste ◽  
Cement Pastes ◽  
Hydration Model

This case study focuses on the quantification of the amorphous hydrate distribution in the microstructure of hardened cement paste. Microtomographic scans of the hardenend cement paste were thresholded based on histogram image analysis combined with microstructural composition obtained from CEMHYD3D hydration model, to separate unhydrated cement grains, crystalline and amorphous hydrates, and capillary pores. The observed spatial distribution of the amorphous hydrate exhibited a strong spatial gradient as the amorphous gel tended to concentrate around dissolving cement grains rather than precipitate uniformly in the available space. A comparative numerical study was carried out to highlight the effect of the spatially (non)uniform hydrate distribution on the compressive strength of the hardened cement paste.

scholarly journals Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1611
Author(s):  
Gintautas Skripkiūnas ◽  
Asta Kičaitė ◽  
Harald Justnes ◽  
Ina Pundienė
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Calcium Nitrate ◽  
Curing Temperature ◽  
Hardened Concrete ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

Calorimetry, rheology and compressive strength of superplasticized cement pastes

1993 ◽  
Vol 23 (4) ◽  
pp. 939-950 ◽  
Author(s):  
M.-A. Simard ◽  
P.-C. Nkinamubanzi ◽  
C. Jolicoeur ◽  
D. Perraton ◽  
P.-C. Aïtcin
Keyword(s):  
Compressive Strength ◽  
Cement Pastes

Mechanical Property of Phosphoaluminate Cement

2010 ◽  
Vol 150-151 ◽  
pp. 1754-1757 ◽  
Author(s):  
Peng Liu ◽  
Zhi Wu Yu ◽  
Ling Kun Chen ◽  
Zhu Ding
Keyword(s):  
Mechanical Property ◽  
Compressive Strength ◽  
Phase Composition ◽  
Electrical Properties ◽  
Pore Size Distribution ◽  
Pore Size ◽  
High Strength ◽  
Curing Time ◽  
Hydration Products ◽  
Resistance Value

The influence of curing time on the mechanical property of the phosphoaluminate cement (PAC) was investigated, and the mechanism was discussed as well. The phase composition and morphology of hydration products, electrical properties, porosity and pore size distribution of PAC cured different age were analyzed with XRD, EIS and MIP. The results showed PAC has the property of early-high strength, and the compressive strength of PAC cured for 1 day was about 70% of 28 days’. The main hydration products of PAC are micro-crystal phase and gel of phosphate and phosphoaluminate which formed compacter microstructure. In addition, there are no calcium hydroxide (CH) and ettringite (AFt) produced during the process of hydration. The compressive strength of PAC increased with age, which was due to more products continuously produced. The ac resistance analysis manifested as the change of the nyquist pattern and resistance value.

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