scholarly journals Rheological behaviors and structure build-up of 3D printed polypropylene and polyvinyl alcohol fiber-reinforced calcium sulphoaluminate cement composites

2021 ◽  
Author(s):  
Mingxu Chen ◽  
Lei Yang ◽  
Yan Zheng ◽  
Laibo Li ◽  
Shoude Wang ◽  
...  
Keyword(s):  
Polyvinyl Alcohol ◽  
Cement Composites ◽  
Fiber Reinforced ◽  
Rheological Behaviors ◽  
Sulphoaluminate Cement ◽  
Polyvinyl Alcohol Fiber ◽  
3D Printed ◽  
Calcium Sulphoaluminate ◽  
Calcium Sulphoaluminate Cement

Sulfate resistance of calcium sulphoaluminate cement

2016 ◽  
Vol 1 (3) ◽  
pp. 131-139 ◽  
Author(s):  
Eric Bescher ◽  
Edward K. Rice ◽  
Chris Ramseyer ◽  
Seth Roswurm
Keyword(s):  
Sulfate Resistance ◽  
Sulphoaluminate Cement ◽  
Calcium Sulphoaluminate ◽  
Calcium Sulphoaluminate Cement

scholarly journals Behavior Deterioration and Microstructure Change of Polyvinyl Alcohol Fiber-Reinforced Cementitious Composite (PVA-ECC) after Exposure to Elevated Temperatures

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5539
Author(s):  
Qing Wang ◽  
Boyu Yao ◽  
Runze Lu
Keyword(s):  
Polyvinyl Alcohol ◽  
Elevated Temperatures ◽  
Heating Temperature ◽  
Polymer Fibers ◽  
Cementitious Composites ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
Explosive Spalling ◽  
Polyvinyl Alcohol Fiber ◽  
Dense Microstructure

In the case of fire, explosive spalling often occurs in cementitious composites due to dense microstructure and high pore-pressure. Polymer fibers were proved to be effective in mitigating such behavior. However, deterioration of these fiber-reinforced cementitious composites inevitably occurs, which is vital for the prediction of structural performance and prevention of catastrophic disaster. This paper concentrates on the behavior and mechanism of the deterioration of polyvinyl alcohol fiber-reinforced engineered cementitious composite (PVA-ECC) after exposure to elevated temperatures. Surface change, cracking, and spalling behavior of the cubic specimens were observed at room temperature, and after exposure to 200 °C, 400 °C, 600 °C, 800 °C, and 1200 °C. Losses in specimen weight and compressive strength were evaluated. Test results indicated that explosive spalling behavior was effectively prevented with 2.0 vol% polyvinyl alcohol fiber although the strength monotonically decreased with heating temperature. X-ray diffraction curves showed that the calcium hydroxide initially decomposed in the range of 400–600 °C, and finished beyond 600 °C, while calcium silicate hydrate began at around 400 °C and completely decomposed at approximately 800 °C. Micrographs implied a reduction in fiber diameter at 200 °C, exhibiting apparent needle-like channels beyond 400 °C. When the temperature was increased to 600 °C and above, the dents were gradually filled with newly produced substance due to the synergistic effect of thermal expansion, volume expansion of chemical reactions, and pore structure coarsening

scholarly journals Crack Resistance and Mechanical Properties of Polyvinyl Alcohol Fiber-Reinforced Cement-Stabilized Macadam Base

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yi Zhao ◽  
Xuan Yang ◽  
Qingyu Zhang ◽  
Naixing Liang ◽  
Yangkai Xiang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Polyvinyl Alcohol ◽  
Crack Resistance ◽  
Fiber Length ◽  
Cement Content ◽  
Strength Test ◽  
Fiber Reinforced ◽  
Polyvinyl Alcohol Fiber ◽  
Reinforced Cement ◽  
Shrinkage Property

A series of tests were carried out to evaluate crack resistance and mechanical properties of polyvinyl alcohol fiber-reinforced cement-stabilized macadam, which is widely used as pavement base or subbase composite material. Three series of cement-stabilized macadam mixtures with cement content of 3.2%, 3.6%, and 4.0% were prepared by incorporating four various contents (0, 0.6, 0.9, and 1.2 kg/m3) and lengths (12, 18, 24, and 30 mm) of polyvinyl alcohol fiber. The optimum polyvinyl alcohol fiber content, fiber length, and cement content were determined based on the mechanical properties of cement-stabilized macadam mixtures. Then, unconfined compressive strength test, compressive resilience modulus test, splitting strength test, flexural tensile strength test, drying shrinkage test, and temperature shrinkage test were carried out in this study. The results show that polyvinyl alcohol fiber-reinforced cement-stabilized prepared by optimum proportions (cement 3.6%, fiber content 0.9 kg/m3, and fiber length 24 mm) has good crack resistance. The incorporation of polyvinyl alcohol fiber can effectively improve compressive strength and splitting strength, while its effect on CRM of cement-stabilized macadam is not remarkable. The anti-dry-shrinkage property and anti-temperature-shrinkage property of the specimens are also drastically improved due to the reinforcement effect of polyvinyl alcohol fiber. Moreover, the crack resistance index is proposed to evaluate the crack resistance of materials. The crack resistance of PVA fiber-reinforced cement-stabilized macadam prepared by optimum proportions is improved by 44.4%. Consequently, the mechanical properties and crack resistance of cement-stabilized macadam are obviously improved by adding polyvinyl alcohol fiber.

Effect of Gypsum on Hydration Degree and Structure of Hardened Paste of Alite-Strontium Calcium Sulphoaluminate Cement

2011 ◽  
Vol 306-307 ◽  
pp. 1024-1028
Author(s):  
Qiu Ying Li ◽  
Ling Chao Lu ◽  
Shou De Wang
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Cement Clinker ◽  
Hardened Cement ◽  
Hydration Degree ◽  
Synthesis Conditions ◽  
Sulphoaluminate Cement ◽  
Calcium Sulphoaluminate ◽  
Calcium Sulphoaluminate Cement ◽  
Curing Age

Synthesis conditions and performance of alite-strontium calcium sulphoaluminate cement have been studied by introducing strontium calcium sulphoaluminate into Portland cement clinker. The effects of gypsum on compressive strength, hydration degree and structure of hardened alite-strontium calcium sulphoaluminate cement paste were studied in this paper. Composition and structure of the hardened cement paste were analyzed by XRD and SEM. Results show that appropriate content of gypsum could contribute to the hydration of alite-strontium calcium sulphoaluminate cement. When gypsum content is 9%, the compressive strengths for 1d, 3d and 28d curing age are 30.7MPa, 59.5MPa and 105.5MPa, and the corresponding hydration degree are 40.4%, 57.5% and 85.8%, respectively. The hydration products of alite-strontium calcium sulphoaluminate cement are mainly ettringite (AFt), Ca(OH)2, C-S-H gel. Large amount of AFt formed at early curing age provides a sound basis for early compressive strength, and a lot of C-S-H gel generated at later curing age increases the density of the hardened paste.

Determination of Tricalcium Silicates Crystal Forms in Belite-Barium Calcium Sulphoaluminate Cement

2014 ◽  
Vol 541-542 ◽  
pp. 204-208
Author(s):  
Yan Ting Zhao ◽  
Xi Chen ◽  
Ling Chao Lu ◽  
Yong Bo Huang ◽  
Jie Zhang
Keyword(s):  
Cement Clinker ◽  
X Ray Diffraction ◽  
Crystal Forms ◽  
Sulphoaluminate Cement ◽  
Cement System ◽  
Calcium Sulphoaluminate ◽  
Diffraction Peaks ◽  
Method Of Extraction ◽  
Calcium Sulphoaluminate Cement

Chemical method of extraction was adopted in the study, and aqueous solution of potassium hydroxide and sucrose (KOSH) was used to obtain the clinker rich in silicate phases (alite and belite) in order to get the crystal forms of tricalcium silicates (C3S) in the belite-barium calcium sulphoaluminate cement clinker. The crystal forms of C3S were finally determined by XRD (X-ray diffraction) spectrums through its characteristic windows of the diffraction spectrums. Results shows that, C3S exists in the innovative cement system mainly in the form of M1; C2.75B1.25A3can completely dissolve in KOSH solution while its dissolution is inhibited in the cement system; after KOSH treatment, diffraction peaks of C4AF disappear totally and peaks of C3A has weakened to great extent; for the cement clinker, the clinker ground for 90min has the best extraction rate.

Sign in / Sign up

Export Citation Format

Share Document