Workability, Strength and Drying Shrinkage of Structural Mortar Containing Forest Biomass Ash in Partial Replacement of Cement

2014 ◽  
Vol 1051 ◽  
pp. 737-742 ◽  
Author(s):  
Sebastiano Candamano ◽  
Fortunato Crea ◽  
Dolores Romano ◽  
Ivan Iacobini

Aim of this work is to investigate the feasibility to implement structural mortar containing forest biomass ash (FBA), produced by a local power plant, in partial replacement of cement. Chemical composition, morphology and pozzolanicity of ash have been evaluated using Energy Dispersive X-ray analysis (EDX), SEM and Chapelle test respectively. Furthermore, fresh state properties and drying shrinkage, compressive and flexural strength of the mortars at different curing times have been investigated. Forest biomass ash at replacement levels of 0%, 10%, 20% e 30% by total binder weight has been used. FBA has been found to show only a very moderate pozzolanicity, while it adversely affect workability of the fresh mortar and compressive strength and drying shrinkage of the hardened mortar. Nevertheless, at a replacement level of 30%wt and after 28 days of curing, mortar showed a compressive strength above 30MPa.

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Mohamed Abd Elrahman ◽  
Pawel Sikora ◽  
Sang-Yeop Chung ◽  
Dietmar Stephan

AbstractThis paper aims to investigate the feasibility of the incorporation of nanosilica (NS) in ultra-lightweight foamed concrete (ULFC), with an oven-dry density of 350 kg/m3, in regard to its fresh and hardened characteristics. The performance of various dosages of NS, up to 10 wt.-%, were examined. In addition, fly ash and silica fume were used as cement replacing materials, to compare their influence on the properties of foamed concrete. Mechanical and physical properties, drying shrinkage and the sorption of concrete were measured. Scanning electron microscopy (SEM) and X-ray microcomputed tomography (µ-CT) and a probabilistic approach were implemented to evaluate the microstructural changes associated with the incorporation of different additives, such as wall thickness and pore anisotropy of produced ULFCs. The experimental results confirmed that the use of NS in optimal dosage is an effective way to improve the stability of foam bubbles in the fresh state. Incorporation of NS decrease the pore anisotropy and allows to produce a foamed concrete with increased wall thickness. As a result more robust and homogenous microstructure is produced which translate to improved mechanical and transport related properties. It was found that replacement of cement with 5 wt.-% and 10 wt.-% NS increase the compressive strength of ULFC by 20% and 25%, respectively, when compared to control concrete. The drying shrinkage of the NS-incorporated mixes was higher than in the control mix at early ages, while decreasing at 28 d. In overall, it was found that NS is more effective than other conventional fine materials in improving the stability of fresh mixture as well as enhancing the strength of foamed concrete and reducing its porosity and sorption.


2021 ◽  
Vol 15 (1) ◽  
pp. 370-380
Author(s):  
David Sinkhonde ◽  
Richard Ocharo Onchiri ◽  
Walter Odhiambo Oyawa ◽  
John Nyiro Mwero

Background: Investigations on the use of waste clay brick powder in concrete have been extensively conducted, but the analysis of waste clay brick powder effects on cement paste is limited. Materials and Methods: This paper discusses the effects of waste clay brick powder on cement paste. Fragmented clay bricks were grounded in the laboratory using a ball mill and incorporated into cementitious mixes as partial replacement of Ordinary Portland Cement. Workability, consistency, setting time, density and compressive strength properties of paste mixes were investigated to better understand the impact of waste clay brick powder on the cementitious paste. Four cement replacement levels of 2.5%, 5%, 7.5% and 10% were evaluated in comparison with the control paste. The chemical and mineral compositions were evaluated using X-Ray Fluorescence and X-Ray Diffractometer, respectively. The morphology of cement and waste clay brick powder was examined using a scanning electron microscope. Results: The investigation of workability exhibited a reduction of slump attributed to the significant addition of waste clay brick powder into the cementitious mixes, and it was concluded that waste clay brick powder did not significantly influence the density of the mixes. In comparison with the control paste, increased values of consistency and setting time of cement paste containing waste clay brick powder confirmed the information available in the literature. Conclusion: Although waste clay brick powder decreased the compressive strength of cement paste, 5% partial cement replacement with waste clay brick powder was established as an optimum percentage for specimens containing waste clay brick powder following curing periods of 7 and 28 days. Findings of chemical composition, mineral composition and scanning electron microscopy of waste clay brick powder demonstrated that when finely ground, fragmented clay bricks can be used in concrete as a pozzolanic material.


2017 ◽  
Vol 36 (3) ◽  
pp. 691-696
Author(s):  
EE Ikponmwosa ◽  
SO Ehikhuenmen

This paper reports the findings on an experimental investigation of the effect of partial replacement of coarse aggregate with ceramic waste on strength properties of concrete. Compressive strength tests were conducted using 150x150x150mm cube specimens, while tensile strength was investigated using 150x300mm cylinder specimens. Results of tests show that workability, density, compressive and flexural strength of concrete decreased with increase in ceramic waste content. The compressive strength at 90 days curing age for the control sample was 24.67 N/mm2. Compressive strength values at 90 days curing age for  25%, 50% and 75% replacement levels were 21.78 N/mm2, 19.85 N/mm2and 17.85 N/mm2 respectively. The decrease in density and strength was due to ceramic waste being lighter and more porous than normal coarse aggregate. Tensile strength of concrete with ceramic waste decline gradually from 8.39 N/mm2 to 6.13 N/mm2 for the control and 75% replacement samples respectively. This could be attributed to the water absorption capacity and external porcelain nature of the waste material. A production cost savings of 10.7% for 1:2:4 concrete mix was noted at 75% replacement level. This study concludes that ceramic waste could be used for both structural and non-structural works and recommends that beyond 75% replacement level, ceramic waste material should not be used in concrete structures where strength is the major consideration. http://dx.doi.org/10.4314/njt.v36i3.5


Elkawnie ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 302
Author(s):  
Muttaqin Hasan ◽  
Teuku Budi Aulia ◽  
Fido Yurnalis

Abstract: Inong Balee Fort is one of the Islamic Kingdom of Aceh heritage built in 1599 by Admiral Malahayati but several parts of the fortress wall have currently been damaged and the stone removed. Indonesian Government plans to restore the fort and this makes it necessary to examine the characteristics of the fortress mortar with a focus on the chemical composition and mineralogical elements. Therefore, mortar powder samples obtained from the fort walls were tested through X-Ray Diffraction (XRD) and the results showed the main composition of mortar is CaCO3 and SiO2 from a mixture of lime and sand while the others are P2O5, MgCO3, and Al2O3. Meanwhile, two mortar mixtures including 1 lime: 2 sand and 1 cement: 2 lime: 3 sand were designed for restoration purposes and they were both found by the XRD analysis results to have a diffraction pattern similar to Inong Balee Fort mortar. However, mortar with 1 lime: 2 sand has a very low compressive strength subsequently it does not meet the specifications of the SNI 6882:2014 and ASTM C270-19a while mortar with 1 cement: 2 lime: 3 sand has a compressive strength that meets the specifications. Therefore, a mortar with 1 cement: 2 lime: 3 sand is recommended to be used for the restoration of Inong Balee Fort.Abstrak: Benteng Inong Balee merupakan salah satu peninggalan Kerajaan Islam Aceh yang dibangun pada tahun 1599 oleh Laksamana Malahayati. Saat ini banyak bagian dinding pasangan batu benteng tersebut sudah rusak dan batunya sudah terlepas dari ikatan mortar. Pemerintah Republik Indonesia berencana melakukan restorasi benteng tersebut. Oleh karena itu perlu diteliti karakteristik mortar pengikat dari pasangan batu benteng tersebut, berupa kandungan senyawa kimia dan mineralnya. Metode yang digunakan untuk karakterisasi adalah dengan melakukan pengujian X-Ray Diffraction (XRD) terhadap bubuk sampel mortar yang diambil dari dinding benteng. Hasil pengujian menunjukkan bahwa komposisi utama mortar pengikatnya adalah CaCO3 dan SiO2 yang menunjukkan bahwa mortar tersebut terbuat dari campuran kapur dan pasir. Disamping itu juga terdapat kandungan senyawa P2O5, MgCO3 dan Al2O3. Selanjutnya untuk keperluan restorasi didesain 2 campuran mortar, yaitu mortar dengan campuran 1 kapur : 2 pasir dan mortar dengan campuran 1 semen : 2 kapur : 3 pasir. Hasil analisis XRD menunjukkan bahwa kedua campuran tersebut mempunyai pola diffraksi yang mirip dengan Benteng Inong Balee. Akan tetapi mortar dengan campuran 1 kapur : 2 pasir mempunyai kuat tekan yang sangat rendah sehingga tidak memenuhi spesifikasi Standar SNI 6882:2014 dan ASTM C270-19a, sedangkan mortar dengan campuran 1 semen : 2 kapur : 3 pasir mempunyai kuat tekan yang memenuhi spesifikasi Standar SNI 6882:2014 dan ASTM C270-19a, sehingga mortar ini disarankan digunakan untuk keperluan restorasi Benteng Inong Balee.


Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5343
Author(s):  
Jorge L. Costafreda ◽  
Domingo A. Martín ◽  
Leticia Presa ◽  
José Luis Parra

This paper shows the results of a study focused on the evolution and properties of mortars made with a mixture of portland cement (PC) and natural mordenite (Mor). To begin, samples of mordenite, cement and sand were studied with X-ray diffraction (XRD), X-ray fluorescence (XRF) and granulometric analysis (GA). Next, mortars with a ratio of 75% PC and 25% mordenite were prepared to determine their initial and final setting times, consistency and density. Continuing, the density, weight and compressive strength of the specimens were determined at 2, 7, 28, 90 and 365 days. Finally, the specimens were studied using SEM, XRD and XRF. The results of the study of the mordenite sample showed a complex constitution where the major mineral component is mordenite, and to a lesser degree smectite (montmorillonite), halloysite, illite, mica, quartz, plagioclase and feldspar, in addition to altered volcanic glass. Tests with fresh cement/mordenite mortar (CMM) showed an initial setting time of 320 min and a final setting time of 420 min, much longer than the 212–310 min of portland cement mortar (PCM). It was established that the consistency of the cement/mordenite mortar (CMM) was greater than that of the PCM. The results of the density study showed that the CMM has a lower density than the PCM. On the other hand, the density of cement/mordenite specimens (CMS) was lower than that of portland cement specimens (PCS). The CMS compressive strength studies showed a significant increase from 18.2 MPa, at 2 days, to 72 MPa, at 365 days, with better strength than PCS at 28 and 365 days, respectively. XRD, XRF and SEM studies conducted on CMS showed a good development of primary and secondary tobermorite, the latter formed at the expense of portlandite; also, ettringite developed normally. This work proves that the partial replacement of PC by mordenite does not have a negative effect on the increase in the mechanical strength of CMS. It indicates that the presence of mordenite inhibits the spontaneous hydration of C3A and controls the anomalous formation of ettringite (Ett). All this, together with the mechanical strength reported, indicates that mordenite has a deep and positive influence on the evolution of the mortar setting and is an efficient pozzolan, meaning it can be used in the manufacture of mortars and highly resistant pozzolanic cement, with low hydration heat, low density, stability in extremely aggressive places and a low impact on the environment.


2019 ◽  
Vol 9 (11) ◽  
pp. 2270 ◽  
Author(s):  
Yubin Jun ◽  
Jae Hong Kim ◽  
Taewan Kim

This study investigated the properties of hardened pastes made with calcium sulfoaluminate expansive agent (CSA), red mud, and silica fume. Five different ratios of 10:90, 20:80, 30:70, 40:60, and 50:50 were applied as the weight ratios of CSA and red mud. Red mud was replaced with 0, 5, and 10% silica fume by weight. Compressive strength, drying shrinkage, XRD, MIP, and SEM/EDS of the hardened pastes were performed. The results indicated that as the amount of CSA increased (i.e., as the amount of red mud decreased) up to 30%, sample strengths showed a tendency to increase. The main reaction product of the pastes was expansive ettringite, which was formed from the consumption of ye’elimite, anhydrite, gypsum, and Ca(OH)2. It was expected that C-S-H would be formed by the reaction of C2S in red mud; however, C-S-H phase was not present, and the pozzolanic activity due to the use of silica fume did not occur. The increase of CSA replacement level was effective for controlling the drying shrinkage of the samples. However, 50% replacement level of CSA induced excessive expansion, leading to the reduction in strength. It was found that the excessive expansion in the sample was reduced by the addition of silica fume.


2020 ◽  
Vol 840 ◽  
pp. 345-350
Author(s):  
Rethy Den ◽  
Rini Dharmastiti ◽  
Nuryono Nuryono ◽  
Leny Yuliatun ◽  
Widjijono Widjijono

The proportion of MTA powder and water is a common factor impacted on the properties of the material in clinical application. The purpose of this research was to determine the compressive strength and porosity of Mineral Trioxide Aggregate (MTA) mixed with varying water-to-powder (WP) ratios. ROOTDENT MTA was investigated. One gram of cement was mixed with 0.28, 0.33 or 0.40 grams of distilled water and was submerged either for 1, 7, or 28 days in the water. The chemical composition of un-hydrated MTA was characterized by X-ray fluorescence. Samples were carried out for compression and porosity test. ROOTDENT MTA was composed primarily of calcium, oxygen, and zirconium. Minor quantities of sodium, aluminum, and silicon were presented in the cement and lack of bismuth was found. The highest mean compressive strength value was MTA with 0.33 WP ratio submerged in the water for 28 days. The percentage of porosity increased as the WP ratio increased. The percentage of porosity submerged in the water for 7 and 28 days showed no significant differences while the lowest porosity was MTA with 1 day in the water.


2015 ◽  
Vol 802 ◽  
pp. 118-123 ◽  
Author(s):  
John Wilmer Bautista ◽  
John Benedict Crockett ◽  
Beatrice Ann Liu ◽  
Timothy John Obra ◽  
Cheryl Lyne Roxas

Drying shrinkage in mortar produces cracks and micro-cracks which affect the durability of a structure. The effects of seawater as a substitute to freshwater and fly ash as a partial replacement for cement were investigated in this study in order to address the predicted water shortage by 2025 and the increasing carbon footprint from carbon dioxide emissions worldwide. Moreover, these materials are also more economical alternatives to freshwater and cement. Rectangular prism specimens with varying fly ash content (10%, 15%, 20%, 25%, and 30%) were cast to measure the drying shrinkage in mortar while 50-mm cube mortar specimens were prepared to determine the compressive strength. This study investigated whether the addition of fly ash and seawater reduced the drying shrinkage of mortar. From the results, it was found that mortar specimens with 20% fly ash replacement achieved the highest early and late strengths. Partial substitution of fly ash would result to shrinkage in mortar while substitution of seawater to freshwater counteracts the effects of fly ash, thus producing less shrinkage. Fly ash content between 20%-25% combined with seawater produces the least shrinkage value without compromising the minimum required compressive strength.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Rayed Alyousef ◽  
Omrane Benjeddou ◽  
Mohamed Amine Khadimallah ◽  
Abdeliazim Mustafa Mohamed ◽  
Chokri Soussi

The marble powder (MP), obtained from waste sludge marble processing, has a high specific surface area; this could mean that it can be used as filler added to self-compacting concrete (SCC). The aim of this experimental work is to study the effects of the cement-MP paste volume on the rheology in the fresh state and the hardened properties (compressive strength) of SCC by a microstructure analysis on paste samples with different amounts of MP. For all pastes, the morphological forms and the chemical composition of the main mineral components were analyzed by the scanning electron microscope (SEM) and X-ray diffraction (XRD). The hydration, microstructure, and mineralogical changes has been studied. Experimental results show that the cement-MP paste volume has significant effects on the self-compacting and the self-leveling properties in the fresh state of SCC. In addition, the paste volume has a significant contribution on the compressive strength of SCC. Results indicate also that the difference in chemical composition between MP and cement have not any contribution on the paste volume effects.


2014 ◽  
Vol 5 (1) ◽  
pp. 11-16
Author(s):  
N. Tamanna ◽  
N. Mohamed Sutan ◽  
I. Yakub ◽  
D. T. C. Lee

 A greater portion of nonrecyclable waste glass is accumulated on landfills creating a serious environmental problem. Recent studies have been carried out to utilize the waste glass in construction as partial replacement of cement. This paper investigates the fineness properties of four sizes glass particles and strength characteristics of mortar in which cement is partially replaced with glass powder in the replacement level with 10%, 20%, 30% and 40%. Mortar cubes containing with varying particle sizes in the ranges of 212 μm, 75 μm, 63-38 μm and lower than 38 μm and in a water to cement ratio 0f 0.50 and 0.45 have been prepared. Room temperature and relative humidity have been maintained 32º and 90% respectively during the curing process. Replacement of 10% cement with glass powder reveals the higher compressive strength at 28days than other levels of replacement. The reduction in compressive strength increases with the level of cement replacement.


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