Preparation of a New Unburned Brick from Ti-Bearing Blast Furnace Slag and PVA Modified by Epikote

2013 ◽  
Vol 785-786 ◽  
pp. 328-331 ◽  
Author(s):  
Xiang Wen Kong ◽  
Li Li Ren ◽  
Xia Ai ◽  
Jing Zhang

A new unburned brick was prepared from the Ti-bearing blast furnace slag as an aggregate and PVA modified by epikote as cementitious materials. The effects of modified PVA and auxiliaries on compressive strength of unburned brick were studied by the orthogonal test method. The results show that samples have better properties and low cost when the samples have a composition of slag dosage 72 %, modified PVA dosage 6%, auxiliary 1 dosage 6%, auxiliary 2 dosage 10%, water 6% and the process conditions of preparing the brick sample were mixing time 1 h, forming time 10 min, forming pressure 40 MPa, and curing time 7 d. The study reveals that the samples properties can meet the standard requirements of excellent grade products (MU20) in GB11945-1999.

2012 ◽  
Vol 512-515 ◽  
pp. 2982-2985
Author(s):  
Xiang Wen Kong ◽  
Dan Wang

The unburned brick was prepared by using the high titania blast furnace slag as an aggregate, styrene-acrylate emulsion as cementing materials and two admixtures. Factors such as amounts of admixtures and styrene-acrylate emulsion, forming pressure and curing time on the properties of the products were studied. The optimal process conditions for preparing the brick sample were as follows: mass fractions of the slag, styrene-acrylate emulsion, admixture 1, admixture 2 and water were respectively 70%, 8%, 8%, 10% and 4%, forming pressure 30 MPa, curing time 7 d. The properties of the brick sample prepared under these process conditions are better than that of MU 25 in GB / T 2542 - 2003.


Author(s):  
Hitoshi Owada ◽  
Tomoko Ishii ◽  
Mayumi Takazawa ◽  
Hiroyasu Kato ◽  
Hiroyuki Sakamoto ◽  
...  

A “realistic alteration model” is needed for various cementitious materials. Hypothetical settings of mineral composition calculated based on the chemical composition of cement, such as Atkins’s model, have been used to estimate the alteration of cementitious material. However, model estimates for the concentration of certain elements such as Al and S in leachate have been different from experimental values. In a previous study, we created settings for a mineralogical alteration model by taking the initial chemical composition of cementitious materials from analysis results in experiments and applying their ratios to certain hydrated cement minerals, then added settings for secondary generated minerals in order to account for Ca leaching. This study of alteration estimates for ordinary portland cement (OPC) in groundwater showed that the change in Al and S concentrations in simulated leachate approached values for actual leachate[1]. In the present study, we develop an appropriate mineral alteration model for blended cementitious materials and conduct batch-type leaching experiments that use crushed samples of blast furnace slag cement (BFSC), silica cement (SC), and fly ash cement (FAC). The cement blends in these experiments used OPC blended with blast furnace slag of 70 wt.%, silica cement consisting of an amorphous silica fine powder of 20 wt.%, and fly ash of 30 wt.%. De-ionized water was used as the leaching solution. The solid-liquid ratios in the leaching tests were varied in order to simulate the alteration process of cement hydrates. The compositions of leachate and minerals obtained from leaching tests were compared with those obtained from models using hypothetical settings of mineral composition. We also consider an alteration model that corresponds to the diversity of these materials. As a result of applying the conventional OPC model to blended cementitious materials, the estimated Al concentration in the aqueous solution was significantly different from the measured concentration. We therefore propose an improved model that takes better account of Al behavior by using a more reliable initial mineral model for Al concentration in the solution.


2021 ◽  
Vol 8 ◽  
Author(s):  
Fusheng Niu ◽  
Yukun An ◽  
Jinxia Zhang ◽  
Wen Chen ◽  
Shengtao He

In this study, the influence of steel slag (SS) content on the strength of the cementitious materials was investigated. The quaternary active cementitious material (CaO-SiO2-Al2O3-SO3) was prepared using various proportions of steel slag (SS), granulated blast furnace slag (BFS), and desulfurized gypsum (DG). The mechanism of synergistic excitation hydration of the cementitious materials was examined using various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectrometry (FTIR). The strength of the mortar test block was initially increased and decreased later with the increase of the SS content. Mortar test block with 20% steel slag, 65% granulated blast furnace slag, and 15% desulfurized gypsum with 0.35 water-binder ratio showed the highest compressive strength of 57.3 MPa on 28 days. The free calcium oxide (f-CaO) in the SS reacted with water and produced calcium hydroxide (Ca(OH)2) which created an alkaline environment. Under the alkaline environment, the alkali-activated reaction occurred with BFS. In the early stage of hydration reaction, calcium silicate hydrate (C-S-H) gel and fibrous hydration product ettringite (AFt) crystals were formed, which provided early strength to the cementitious materials. As the hydration reaction progressed, the interlocked growth of C-S-H gel and AFt crystals continued and promoted the increase of the strength of the cementitious system.


2020 ◽  
Vol 35 (4) ◽  
pp. 15-20
Author(s):  
Quyen V. Trinh ◽  
Gábor Mucsi ◽  
Thai V. Dang ◽  
Ly P. Le ◽  
Van H. Bui ◽  
...  

In this study, the material characterization of Vietnamese ground coal slag and ground granulated blast furnace slag (GGBFS), such as particle size distribution, chemical composition, bulk density and particle density are shown. The geopolymer specimens were prepared by mixing an 80 m/m% mass of solid materials (ground coal slag and GGBFS in a different ratio) with 20 m/m % of a 10M NaOH alkaline activator. A systematic experimental series was carried out in order to optimize the preparation process. In that series, the heat curing temperature was 60°C for 6 hours, and then selected specimens were heat treated at a high temperature (1000 °C) for 1 hour. After 7 days of ageing, the physical properties of the geopolymer (compressive strength, specimen density) were measured. Also, after 180 days of ageing, the pH values of water in the geopolymer leaching preparation were determined. The results show that the geopolymer can be used for refractory applications due to its good heat resistance properties. However, geopolymers that were heated at 1000 °C had lower compressive strength, specimen density and pH values of water containing the geopolymer than those that were cured at 60 °C.


2013 ◽  
Vol 325-326 ◽  
pp. 71-74
Author(s):  
Yun Feng Li ◽  
Dong Sheng Zhang ◽  
Li Xu

The shrinkage cracking of concrete plays an important role to the accelerated deterioration and shortening the service life of concrete structures. The mineral admixture will be a perfect component of high performance concrete and its utilization will be a valuable resource for recycling. Early age cracking characteristics of concrete with compound admixtures, such as steel slag, blast furnace slag, fly ash, are studied in this paper using plate test method. The better anti-cracking performance of concrete will be realized when blast furnace slag replacing cement at 30%, steel slag and fly ash as the equal mixture components replacing cement at 30%, three kinds of admixtures replacing cement at 30% under the proper proportion.


Sign in / Sign up

Export Citation Format

Share Document