scholarly journals Development of Alkaline-Activated Self-Leveling Hybrid Mortar Ash-Based Composites

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1829 ◽  
Author(s):  
Luís Tambara Júnior ◽  
Malik Cheriaf ◽  
Janaíde Rocha

This study investigated the reactivity properties of self-leveling hybrid alkali-activated cements, such as ordinary Portland cement (OPC) and its residual precursors, coal bottom ash (BA), and rice husk ash (RHA). Due to the relatively low reactivity of BA, binary mixes were produced with OPC using contents of 2.5–30% in the treated BA samples. Furthermore, ternary mixes were prepared in proportions of 25%, 50%, and 75% with RHA as a replacement material for the OPC (mix with 90%:10% BA:OPC). For all of the mixes the spreading behaviors were fixed to obtain a self-levelling mortar, and dimensional changes, such as curling and shrinkage, were performed. Mortars with 30% OPC reached a compressive strength of 33.5 MPa and flexural strength of 7.53 MPa. A scanning electron microscope (SEM) and X-ray powder diffraction (XRD) were used to indicate the formation of N-A-S-H and a (N,C)-A-S-H gel, similar to the gel with trace of calcium. The best performance was achieved when the binary mix produced 10% OPC. A hybrid mortar of OPS-BA presented 10 times lower susceptibility to curling than an OPC mortar. The results showed that both ashes reduced the shrinkage and curling phenomena.

2021 ◽  
Author(s):  
Gude Reddy Babu ◽  
Pala Gireesh Kumar ◽  
Nelluru Venkata Ramana ◽  
Bhumireddy Madhusudana Reddy

The present examination illustrates the impact on the hardened and fresh cement mortar and cement with the inclusion of nanosilica of size 40 nm in various environmental conditions (UltraTech, India). It is quite notified that an elevation in compressive strength as well as flexural strength along with an improvisation in the performance and life span of cement mortar. The samples of M5 grade blended with a ninety percentage of concrete and remaining with nanosilica was identified to have a finer working elevation in as well as in standards when collated with the conventional cement mortar. The corollary of hardened and fresh cement, strength parameters were looked upon with the aid of XRD (X-ray Diffraction). Also, the SEM (Scanning Electron Microscope) test holds a predominant role in analysis.


2018 ◽  
Vol 879 ◽  
pp. 166-170 ◽  
Author(s):  
Varinthorn Boonyaroj ◽  
Samanya Sanguanpak ◽  
Witaya Shongkittikul

Utilizing para wood ash can offer an alternative method of adding value to agricultural wastes and help to conserve the environment. The feasibility of using para rubber leaves as an environmentally friendly material for prototype lightweight flat sheet production was investigated. Properties of lightweight flat sheet made from different proportions of para rubber leaves mixed with para wood ash were compared with ordinary Portland cement (OPC). Morphology and element compositions of untreated and treated para rubber leaves with 20% NaOH solution were observed using a field emission scanning electron microscope (FE-SEM) with energy dispersive X-ray spectroscopy (EDS). Results showed that untreated para rubber leaves consisted mainly of the elements carbon (C) and oxygen (O), accounting for 80.35% and 17.55% by weight, respectively, with minor amounts of other elements. Treated para rubber leaves consisted mainly of C, O, and calcium (Ca) at 69.53%, 28.55%, and 1.25% by weight, respectively. Bulk density and compressive strength of the control cement paste were 1.85 g/cm3and 47.78 MPa, respectively at 28 days curing. The compressive strength of the cement composite decreased with an increase in the para rubber leaves volume fraction.


2013 ◽  
Vol 753-755 ◽  
pp. 572-575
Author(s):  
Shu Xian Liu ◽  
Shao Bo Wei

This paper discussed the experimental results of exploiting brick materials with iron tailing materials in Tanshang area. Through preparation of iron tailing bricks, the technical flow and production proportion was obtained. The results show that a burning-and steam curing-free brick product with a compressive strength of 28.30 MPa and Flexural strength of 5.63 MPa as the following: iron tailing; fly ash; sand; CaO; gypsum; cement. And long-term properties of a burning-and steam curing-free brick is also studied by experiments in this paper. Put forward a new technique of making materials with iron tailing. At the same time, the micro mechanism of iron tailing brick was also studied with X-Ray Diffractometer (XRD) and Scanning Electron Microscope (SEM).


2011 ◽  
Vol 306-307 ◽  
pp. 961-965
Author(s):  
Chao Nan Yin ◽  
Ling Chao Lu ◽  
Shou De Wang

The influence of P2O5on the properties of alite-calcium strontium sulphoaluminate cement was researched by means of X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) and petrographic analysis. The results show that the optimal content of P2O5is 0.3% and the compressive strength of the cement at 1, 3, 28d are 27.0, 59.1, 110.9MPa when the calcining temperature is 1350°C. P2O5mainly exists in the belite and a suitable amount of P2O5can promote the formation of C1.5Sr2.5A3and alite. When the content of P2O5is higher than 0.3%, the formation of C1.5Sr2.5A3and alite can be hindered. P2O5can enhance the hydration heat evolution rate in the acceleration period and the hydrate heat of cement containing P2O5increases slightly.


2020 ◽  
Vol 10 (15) ◽  
pp. 5190
Author(s):  
Danutė Vaičiukynienė ◽  
Dalia Nizevičienė ◽  
Aras Kantautas ◽  
Vytautas Bocullo ◽  
Andrius Kielė

There is a growing interest in the development of new cementitious binders for building construction activities. In this study, biomass bottom ash (BBA) was used as aluminosilicate precursor and phosphogypsum (PG) was used as a calcium source. The mixtures of BBA and PG were activated with the sodium hydroxide solution or the mixture of sodium hydroxide solution and sodium silicate hydrate solution. Alkali activated binders were investigated using X-ray powder diffraction (XRD), X-ray fluorescence (XRF) and scanning electron microscopy (SEM) test methods. The compressive strength of hardened paste and fine-grained concrete was also evaluated. After 28 days, the highest compressive strength reached 30.0 MPa—when the BBA was substituted with 15% PG and activated with NaOH solution—which is 14 MPa more than control sample. In addition, BBA fine-grained concrete samples based on BBA with 15% PG substitute activated with NaOH/Na2SiO3 solution showed higher compressive strength compered to when NaOH activator was used −15.4 MPa and 12.9 MPa respectfully. The NaOH/Na2SiO3 activator solution resulted reduced open porosity, so potentially the fine-grained concrete resistance to freeze and thaw increased.


2013 ◽  
Vol 361-363 ◽  
pp. 682-685
Author(s):  
Chao Qian ◽  
Wen Yuan Gao ◽  
Chun Yuan Luo ◽  
Li Dong Tuo ◽  
Hai Yuan Li ◽  
...  

Insulation materials with flexural strength 5.238 MPa and porosity 39.24% obtained at 1050 °C for 0.5 h show that its bulk density of the materials decreased down to 1.252 g/cm3using clay as aggregate. Due to change the amount of sugar filter mud, the porosity arises from 37.07% to 39.24% and the thermal conductivity decreases from 0.086 to 0.052 W·m-1·K-1. The clay and wastes were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and chemical elemental analysis. The main crystalline phases of sample observed by XRD are quartz, mullite and anorthite. The insulation materials were manufactured from clay and the optimal proportion of wastes.


2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Wenwei Lin ◽  
Fan Fei ◽  
Qunjie Li

The sulfur concrete samples were prepared by the optimized process, which were mixed with cement, fly ash and slag, respectively. The influence of the type and content of filler on the compressive strength of sulfur concrete was studied. The phase and micromorphology of filler and sulfur mixture were characterized by X-ray diffraction and scanning electron microscope, and the bonding mode was studied. The results show: the cement filler has the best effect on the compressive performance of sulfur concrete,and the compressive strength is 87.2 MPa by adding cement filler with the same quality as sulfur; there is no chemical reaction between filler and sulfur, and the filler is physically bonded to sulfur matrix.


Activated Slag (AAS) and Fly Ash (FA) based geopolymer concrete a new blended alkali-activated concrete that has been progressively studied over the past years because of its environmental benefits superior engineering properties. Geopolymer has many favorable characteristics in comparison to Ordinary Portland Cement. Many base materials could be utilized to make geopolymer with the convenient concentration of activator solution. In this study, the experimental program composed of two phases; phase on divided into four groups; Group one deliberated the effect of sodium hydroxide molarity and different curing condition on compressive strength. Group two studied the effect of alkali activated solution (NaOH and Na2SiO3) content on compressive strength and workability. The effect of sand replacement with slag on compressive strength and workability was explained in group three. Group four studied the effect of slag replacement with several base materials Fly Ash (FA), Ordinary Portland Cement (OPC), pulverized Red Brick (PRB), and Meta Kaolin (MK). Phase two contains three mixtures from phase one which had the highest compressive strength. For each mixture, the fresh concrete test was air content. In addition the hardened concrete tests were the compressive strength at 3, 7, 28, 90, 180, and 365 days, the flexural strength at 28, 90, and 365 days, and the young's modulus at 28, 90, and 365 days. Moreover; the three mixtures were exposed to elevated temperature at 100oC, 300oC, and 600oC to study the effect of elevated temperature on compressive and flexural strength.


2013 ◽  
Vol 807-809 ◽  
pp. 1266-1269 ◽  
Author(s):  
Atthakorn Thongtha ◽  
Somchai Maneewan ◽  
Chantana Punlek ◽  
Yothin Ungkoon

The comparison of microstructure and mechanical properties between the autoclaved aerated concrete (AAC) and the autoclaved aerated concrete consist of sugar sediment (AAC-SS) was investigated in this work. The microstructure of AAC and AAC-SS was analyzed by the scanning electron microscopy (SEM). The mechanical properties of AAC and AAC-SS were focused on the compressive strength, the density, the water absorption and the flexural strength. To comfirm the tobermorite phase, the phase formation of the samples was tested using X-ray diffraction (XRD). It was found that the microstructure of AAC and AAC-SS surface was the finer needle-like crystalline morphology. The compressive strength (5.9 N/mm2) and flexural strength (1.82 N/mm2) of AAC-SS were higher than that of the AAC (5.0 N/mm2 and 1.64 N/mm2). While, the value of density (0.60 g/cm3) and humidity (23.59%) of AAC-SS had little less than that of the AAC (0.61 g/cm3 and 24.11%). The increasing of the tobermorite phase, which was added by the sugar sediment, had affected to the improvement of the mechanical properties. The specimens of both AAC and AAC-SS were claimed in quality class of 4, which based on the Thai Industrial Standard 1505-1998.


2011 ◽  
Vol 250-253 ◽  
pp. 33-39
Author(s):  
Xiao Lu Yuan ◽  
Bei Xing Li ◽  
Shang Chuan Zhao ◽  
Shi Hua Zhou

This paper investigates mechanical characteristics of concrete exposed to external flexural load, de-icing salt and freeze-thaw cycles. Concrete specimens made with ordinary Portland cement or ordinary Portland cement incorporating fly ash with the replacement of 10% or 20%, or 0.7/10000 air-entraining agent and 20% fly ash, or ground blast furnace slag with the replacement of 15% or 30%, were made and exposed to flexural load, freeze-thaw and de-icing salt environment. Mechanical properties of concrete including compressive strength and flexural strength were measured. Phase composition of samples was determined by means of x-ray diffraction (XRD). Results indicate that increasing flexural stress ratios reduced compressive strength and flexural strength of concrete, and presented higher improvement of mineral admixtures in concrete strength. Incorporation of mineral admixtures and air-entraining agent decreased the loss of concrete strength. X-ray diffraction analysis showed the presence of abundant calcium chloroaluminate and ettringite in paste samples.


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