The Development of Microstructure in Calcium Sulphoaluminate Expansive Cement

1991 ◽  
Vol 245 ◽  
Author(s):  
John Herrick ◽  
Karen L. Scrivener ◽  
Peter L. Pratt
Keyword(s):  
Thermal Analysis ◽  
Portland Cement ◽  
Calcium Hydroxide ◽  
Ordinary Portland Cement ◽  
Hydration Reaction ◽  
Free Lime ◽  
Apparent Change ◽  
Backscattered Electron ◽  
Calcium Sulphoaluminate ◽  
Individual Particles

ABSTRACTUsing backscattered electron images, it is shown that an expansive clinker is polymineralic in nature, with individual particles containing the constituents (lime, anhydrite and anhydrous calcium sulphoaluminate) to form ettringite on hydration. The hydration reaction with time of a simple paste of a mixture of this expansive clinker with Ordinary Portland Cement (OPC) has been monitored using backscattered electron images, and the formation of ettringite and a change in the morphology of the calcium hydroxide formed from the added free lime from the expansive clinker is observed. Thermal analysis studies on pastes of the pure expansive clinker have confirmed this apparent change in morphology.

scholarly journals Thermal Properties of Calcium Sulphoaluminate Cement as an Alternative to Ordinary Portland Cement

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7011
Author(s):  
Małgorzata Gołaszewska ◽  
Barbara Klemczak ◽  
Jacek Gołaszewski
Keyword(s):  
Activation Energy ◽  
Portland Cement ◽  
Apparent Activation Energy ◽  
Thermal Behaviour ◽  
Ordinary Portland Cement ◽  
Isothermal Calorimetry ◽  
Heat Of Hydration ◽  
Curing Temperature ◽  
Cement Pastes ◽  
Calcium Sulphoaluminate

This paper presents the results of research into the heat of hydration and activation energy of calcium sulphoaluminate (CSA) cement in terms of the dependence on curing temperature and water/cement ratio. Cement pastes with water/cement ratios in the range of 0.3–0.6 were tested by isothermal calorimetry at 20 °C, 35 °C and 50 °C, with the evolved hydration heat and its rate monitored for 168 h from mixing water with cement. Reference pastes with ordinary Portland cement (OPC) were also tested in the same range. The apparent activation energy of CSA and OPC was determined based on the results of the measurements. CSA pastes exhibited complex thermal behaviour that differed significantly from the thermal behaviour of ordinary Portland cement. The results show that both the w/c ratio and elevated temperature have a meaningful effect on the heat emission and the hydration process of CSA cement pastes. The determined apparent activation energy of CSA revealed its substantial variability and dependence, both on the w/c ratio and the curing temperature.

Physical-Chemical Studies of the Process of Condensation of a Clinker-Free Binder

2022 ◽  
Vol 906 ◽  
pp. 47-52
Author(s):  
Maria Badalyan ◽  
Amalya Karapetyan ◽  
Hovsep Hoveyan
Keyword(s):  
Portland Cement ◽  
Calcium Hydroxide ◽  
Water Resistance ◽  
Volcanic Rocks ◽  
Mineralogical Composition ◽  
Free Lime ◽  
Hardening Process ◽  
Chemical Studies ◽  
The Difference ◽  
Physical And Chemical

The possibility of using a clinker-free binder as an alternative to expensive and energy-intensive Portland cement is being considered. The pozzolanizing effect of volcanic rocks is presented, where along with the binding of calcium hydroxide by silica to hydrosilicates, the binding of calcium hydroxide by “free” alumina to hydroaluminates also takes place. In the process of hardening of the clinker-free binder, the phase mineralogical composition of the formed new formations differs from the new formations that are synthesized during hardening of traditional Portland cement, which explains the difference in their properties. The new formations that are formed during the hardening process of clinker-free cements are mainly low-basic hydrosilicates, and alkaline aluminosilicates give the cast-in-place stone water resistance, frost resistance, waterproofing, etc., in a word, durability. Physical and chemical studies of the hardening process of clinker-free lime-igneous cements have been carried out, which indicates the possibility of replacing the energy-intensive Portland cement with cheaper clinker-free cement.

Revisiting the iron-rich “ordinary Portland cement” towards valorisation of wastes: study of Fe-to-Al ratio on the clinker production and the hydration reaction

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
David Ariño Montoya ◽  
Nikolaos Pistofidis ◽  
Giannis Giannakopoulos ◽  
Remus Ion Iacobescu ◽  
Marios S. Katsiotis ◽  
...  
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Hydration Reaction ◽  
Clinker Production

PENGARUH JENIS SEMEN DAN PENAMBAHAN SILICA FUME TERHADAP KEKUATAN DAN DURABILITAS BETON

2012 ◽  
Vol 2 (1) ◽  
pp. 25
Author(s):  
Ariyadi Basuki ◽  
Maulana Ikhwan Sadikin
Keyword(s):  
Portland Cement ◽  
Silica Fume ◽  
Ordinary Portland Cement ◽  
Composite Cement

Dalam penelitian ini dilakukan serangkaian pengujian untuk mengetahui sifat fisik dari material penyusun (agregat), yang kemudian dirancang komposisi rencana beton dengan mutu K250 (normal/kontrol) dan K250 dengan aditif Silica Fume 10% dari berat semen. Variasi campuran menggunakan tiga tipe semen yang berbeda yaitu Ordinary Portland Cement (OPC)/ Semen Tipe I, Portland Composite Cement (PCC) dan Semen Tipe II. Proses dilanjutkan dengan pembuatan sampel uji silinder berukuran 15 cm x 30 cm (karakteristik kuat tekan, ketahanan sulfat), sampel uji prisma berukuran 20 cm x 20 cm x 12 cm (karakteristik permeabilitas) dan sampel uji kubus berukuran 15 cm x 15 cm x 15 cm (untuk penetrasi klorida). Pengamatan dilakukan untuk melihat karakteristik beton K250 dengan penambahan silica fume 10%, dibandingkan dengan beton normal sebagai acuan, serta aplikasinya dalam lingkungan normal maupun asam (Sulfat, Klor). Hasil kuat tekan memperlihatkan, bahwa campuran dengan menggunakan semen PCC memiliki nilai kuat tekan rata-rata diatas semen OPC. Penambahan silica fume pada campuran semen PCC akan menaikkan nilai kuat tekan sebesar 4,2% dibandingkan beton normal dengan produk semen yang sama, meskipun nilai rasio air-semen nya membesar menjadi 0,71 karena penambahan air. Nilai kuat tekan terbesar diperoleh untuk campuran beton dengan semen Tipe II. Campuran dengan semen PCC (2) menunjukkan nilai penetrasi yang lebih kecil dibandingkan campuran lainnya, hal ini mengindikasikan produk beton yang terbentuk memiliki kepadatan yang lebih baik dari produk campuran lainnya dan tidak porous, sehingga dapat dikatakan memiliki tingkat durabilitas yang cukup baik. Untuk ketahanan terhadap serangan sulfat, beton dengan menggunakan campuran semen tipe II mengalami tingkat pelapukan/penggerusan penampang (scaling) yang lebih besar dibandingkan campuran beton lainnya, meskipun begitu hal ini tidak mempengaruhi nilai kuat tekannya. Untuk produk dengan semen PCC, serangan sulfat tidak mempengaruhi nilai kuat tekannya, bahkan cenderung naik bila dibandingkan pada usia 28 hari.Kata kunci: aspek durabilitas, tipe semen, pemanfaatan silica fume

Utilization of petroleum sludge wastes for increasing productivity of ordinary portland cement

2021 ◽  
Vol 19 (4) ◽  
pp. 315-328
Author(s):  
N.M. Khalil ◽  
Yousif Algamal
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Production Capacity ◽  
Hydration Product ◽  
High Energy ◽  
Cement Industry ◽  
Blended Cements ◽  
Petroleum Waste ◽  
Waste Sludge ◽  
Suitable Amount

This work aims at maximum exploitation of petroleum waste sludge as additive to portland cement to prepare blended cements and hence increasing its production capacity without further firing. This will decrease the main cement industry problems involving environmental pollution such as releasing gases and high-energy consumption during industry and hence maximizes the production economics. Six batches of ordinary portland cement (OPC) mixed with different proportions of petroleum waste sludge (PWS) donated as C1 (control batch contains no PWS), C2 (contains 90 wt.% of OPC+10 wt.% of PWS), C3 (contains 80 wt.% of OPC+20 wt.% of PWS), C4 (contains 70 wt.% of OPC+30 wt.% of PWS), C4 (contains 60 wt.% of OPC+40 wt.% of PWS) and C6 (contains 50 wt.% of OPC+50 wt.% of PWS), were prepared and mixed individually with the suitable amount of mixing water. Cement mixes C2, C3 and C4 showed improved cementing and physicomechanical properties compared with pure cement (C1) with special concern of mix C4. Such improvement is due to the relatively higher surface area as well as the high content of kaolinite and quartz in the added PWS (high pozzalanity) favoring the hydration process evidenced by the increase in the cement hydration product (portlandite mineral (Ca (OH) 2).

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