scholarly journals Optimization of calcium carbonate content on synthesis of aluminum foam and its compressive strength characteristic

Author(s):  
Sutarno ◽  
Bagja Nugraha ◽  
Kusharjanto
2012 ◽  
Vol 450-451 ◽  
pp. 495-498 ◽  
Author(s):  
Gui Yun Wang ◽  
Ling Chao Lu ◽  
Shou De Wang

Different amounts of shell and calcium carbonate were added into the Portland cement, their influences on the compressive strength, sulfate corrosion resistance, hydration heat and porosity of the hardened cement paste were studied. Results show that with the increasing of shell content, the compressive strength decreases, however, modest reduction; as the increase of calcium carbonate content, the strength first increases and then decreases, the compressive strength reaches the highest value when the content is 15%. After addition of shell and calcium carbonate, the initial hydration reaction rate accelerates, meanwhile the induction period and acceleration period are brought forward. With the raising of shell and calcium carbonate content, the corrosion resistance coefficient increases gradually, and the sulfate corrosion resistance increases as well. The proportion of the harmless hole which diameter is smaller than 50nm increases after adding the shell and calcium carbonate, it’s beneficial to improve the performance of concrete.


Author(s):  
Minjun Yang ◽  
Christopher Batchelor-McAuley ◽  
Samuel Barton ◽  
Rosalind E.M. Rickaby ◽  
Heather A. Bouman ◽  
...  

1946 ◽  
Vol 36 (4) ◽  
pp. 283-288 ◽  
Author(s):  
Cyril Tyler

1. The daily retention of calcium, carbonate, phosphorus and chloride was studied using four birds and changing the calcium carbonate content of the ration every 5 days for 15 days.2. It was shown that high calcium diets result in a much lower retention of calcium and thin-shelled eggs are produced.3. Retention of calcium was higher in the laying than in the non-laying bird when calcium carbonate was fed.4. High calcium diets depressed the retention of phosphorus, and in one case the retention was negative, even when no eggs were laid. Laying birds gave negative values for retention because of the heavy phosphorus excretion associated with egg laying.5. High calcium diets also depressed the retention of chloride, and on occasion led to negative retention values.


2021 ◽  
Vol 16 (2) ◽  
pp. 143-157
Author(s):  
Hiroaki SANO ◽  
Mikio YAMADA ◽  
Hirofumi KITAJIMA ◽  
Tukasa KASHIWABARA ◽  
Mikihito FURUKAWA ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5631
Author(s):  
Lu Wang ◽  
Shuhua Liu

This paper presents an efficient method of microbial-induced calcite precipitation (MICP) for cementation of sand particles. First, the influence of initial pH value of the culture medium on the growth of bacteria was discussed. Then, the compressive strength and calcium carbonate content of cemented sand columns with different sand particle sizes were measured to indicate the cementation effectiveness. The microstructure of cemented sand columns as well as the mineral composition and distribution of calcium carbonate were characterised by means of scanning electron microscopy-energy dispersive spectrometer (SEM-EDS) and X-ray diffraction (XRD). The results showed that the urease-producing bacteria S. pasteurii can be cultured at the initial pH values of 7–10, while a higher pH (e.g., 11) would hinder its growth and decrease its urease activity. The injection method of MICP with high standing time can cement sand columns effectively. Small average sand particle size of sand columns and high injection cycles can facilitate the gain of compressive strength, while calcium carbonate content of sand column higher than 8% can promote the increase of compressive strength. XRD results indicate that the fine grains generated on the surface of sand particles are calcite. The distribution of calcite on sand particles’ surface is broad and uniform. First, calcite was precipitated on the surface of sand particles, and then a precipitation layer was formed, which would connect sand particles through its high enough thickness and contribute to the development of compressive strength of the whole sand column.


Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5066
Author(s):  
Maria Emiliana Fortună ◽  
Andrei Lobiuc ◽  
Lucian-Mihai Cosovanu ◽  
Maria Harja

In the present paper, aspects concerning the obtained and characterization of additive systems used for maximizing filler retention, and the effects on paper properties, were investigated. The effects of retention additives over properties of paper, containing fibers from in-situ loading (IS-CCP), were analyzed against the effects of additives over properties of paper containing fibers from conventional loading, obtained by the addition of calcium carbonate in precipitated form (CCP). The physico-mechanical properties were analyzed by various analyses and investigations: calcium carbonate content, X-ray diffraction, scanning electron microscopy (SEM) images, optical and mechanical properties, in order to develop the best systems of retention additives for obtaining higher retention loads for making paper with high content of nano-filler material. The obtained results reveal that at the same level of calcium carbonate content, all paper samples with in-situ loading had higher the optical and mechanical properties than the paper obtained by conventional loading in all cases the additives studied. For all studied properties, nanoparticles had a positively influence over paper properties.


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