Study of Mortars Made with Natural and Artificial Pozzolans

The objective of this work is to evaluate the thermal activation potential of clay soils, particularly the clay fraction of dam mud, for the production of artificial pozzolan which can be substituted to cement in concrete and mortars applications and also to make a comparative study with the natural pozzolan available in the area of Beni Saf in considerable quantities. The research study is carried out on three mortars 10, 20 and 30% of natural pozzolan of Beni Saf and artificial pozzolan from the mud calcined at 850 ° C / 3 hours of the dredged sediments of the dams of Fergoug and Ouizert, and on a control mortar without additions for the need of comparison. Several physical, mechanical, microstructural and sustainable tests have been carried out to carry out this research study: maneuverability in the fresh state, impeded shrinkage, mechanical performance, absorption, acid attack (5% CH3COOH, 5% HNO3 and 5% H2SO4), mass loss and pH reading follow-up in the hardened state. Compressive strengths indicate that pozzolan-based mortars have the best results in particular over the long term, whereas the results of acid attack tests show that the calcined mud has a significantly greater influence than natural pozzolan

PENGARUH PENAMBAHAN POZZOLAN TERHADAP SIFAT MEKANIS DAN ABSORPSI BETON BUSA (FOAMED CONCRETE)

Penelitian ini bertujuan untuk mengetahui pengaruh penambahan pozzolan sebagai bahan pengisi terhadap sifat mekanis dan absorpsi beton busa. Sifat mekanis yang diteliti adalah kuat tekan, kuat tarik belah, dan kuat tarik lentur. Benda uji yang digunakan untuk kuat tekan adalah silinder berdiameter 10 cm dan tinggi 20 cm sebanyak 63 benda uji, untuk kuat tarik belah silinder berdiameter 15 cm dan tinggi 30 cm sebanyak 21 benda uji, dan untuk kuat tarik lentur balok ukuran 40 cm ? 10 cm ? 10 cm sebanyak 21 benda uji dengan Faktor Air Semen (FAS) yang digunakan adalah 0,5. Variabel pada penelitian ini meliputi variasi SG (Specific Gravity) yaitu 1,2; 1,4; dan 1,6 serta variasi persentase pozzolan yaitu 0%; 10%; dan 20%. Pozzolan yang digunakan berasal dari Desa Beurandeh Kecamatan Mesjid Raya-Ujong Batee, Aceh Besar. Pozzolan yang digunakan telah dibersihkan dan diayak lolos saringan 4,76 mm. Hasil pengujian kuat tekan terjadi peningkatan yang paling besar pada SG 1,4 pada persentase pozzolan 10% sebesar 34.543% (179.618 kg/cm2), semakin besar SG pada beton busa dengan penambahan pozzolan, maka kuat tekan yang diperoleh akan semakin besar. Pada pengujian kuat tarik belah terjadi peningkatan yang paling besar pada SG 1,2 pada persentase pozzolan 20% sebesar 49.098% (16.081 kg/cm2), semakin besar SG pada beton busa dengan penambahan pozzolan, maka kuat tarik belah yang diperoleh akan semakin besar. Pada pengujian kuat tarik lentur terjadi peningkatan yang paling besar pada SG 1,2 dengan persentase pozzolan 20% sebesar 57.550% (27.520 kg/cm2), semakin besar SG pada beton busa dengan penambahan pozzolan, maka kuat tarik lentur yang diperoleh akan semakin besar. Pada pengujian absorpsi penyerapan kadar air yang paling sedikit yatu pada SG 1,6 dengan penambahan pozzolan 20% yaitu sebesar 16,99%, semakin besar SG pada beton busa dengan penambahan pozzolan, maka absorpsi air yang diperoleh akan semakin kecil. Hal ini menunjukkan bahwa penggunaan pozzolan sebagai bahan penambah mempengaruhi kuat tekan, kuat tarik belah, kuat tarik lentur dan absorpsi beton busa

Influence of Curing Age and Mix Composition on Compressive Strength of Volcanic Ash Blended Cement Laterized Concrete

This study investigates the influence of curing age and mix proportions on the compressive strength of volcanic ash (VA) blended cement laterized concrete. A total of 288 cubes of 100mm dimensions were cast and cured in water for 3, 7, 28, 56, 90 and 120 days of hydration with cement replacement by VA and sand replacement by laterite both ranging from 0 to 30% respectively while a control mix of 28-day target strength of 25N/mm2 (using British Method) was adopted. The results show that the compressive strength of the VA-blended cement laterized concrete increased with the increase in curing age but decreased as the VA and laterite (LAT) contents increased. The optimum replacement level was 20%LAT/20%VA. At this level the compressive strength increased with curing age at a decreasing rate beyond 28 days. The target compressive strength of 25N/mm2 was achieved for this mixture at 90 days of curing. VA content and curing age was noted to have significant effect (α 0.5) on the compressive strength of the VA-blended cement laterized concrete

Influence of substrate annealing on inducing Ti3+ and oxygen vacancy in TiO2 thin films deposited via RF magnetron sputtering

Nano-crystalline TiO2 has been prepared by RF magnetron sputtering at varied substrate temperatures ranging from 200 to 500 °C. The alteration of oxygen and titanium atom in TiO2 at uppermost surface is clearly observed on the effect of annealing temperature by Auger Electron Spectroscopy (AES) technique. The measurement of peak to peak value of Ti and O transition line at 400 °C indicates the surface chemical state of O2 in TiO2 thin films defect at surface and Fermi level was analyzed using the X-Ray Photoelectron Spectroscopy (XPS). The Ti 2p observation of pre and post surface treatment shows the concentration of Ti3+ is seven times higher after post sputtered for sample 200 °C. Ti3+ decrease by increasing temperature. The Ti3+-oxygen vacancy which also assigned as Ti2O3 occurred in all sample, yet sample deposited at 400 °C gives nearest binding energy for Ti2O3. This observation also supported by The Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) analysis which shows highest total ion count for positive polarity is O+ for sample at 300 °C and Ti ion dominant is Ti2O3 + for sample at 400 °C. Based on the analyses, it is clearly seen that high defect of Ti3+-oxygen vacancy which is located between surface layer and fermi level state, this defect levels was created at surface layer at low annealing temperature. However, increasing temperature leads to defect creation on bellow surface layer which consider as within fermi level laye

PENGARUH PENGUNAAN PASIR POZZOLAN SEBAGAI SUBSTITUSI AGREGAT HALUS TERHADAP KUAT TARIK BELAH, KUAT TARIK LENTUR DAN KUAT GESER MURNI BETON MUTU TINGGI

Beton mutu tinggi memiliki rasio kekuatan terhadap berat (strength to weight Ratio) yang sangat kecil, oleh karna itu digunakanlah pasir pozzolan sebagai substitusi agregat halus karena pasir pozzolan memiliki berat jenis lebih kecil daripada pasir beton konvensional. Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan pozzolan alam sebagai substitusi agregat halus pada beton mutu tinggi serta nilai kadar substitusi dari pasir pozzolan yang dibutuhkan untuk mencapai kuat tarik belah, kuat tarik lentur dan kuat geser murni maksimum. Pada penelitian ini dilakukan pengujian pada umur 28 hari dengan perawatan pada suhu ruangan. Persentase pasir pozzolan yang disubstitusikan pada campuran beton mutu tinggi yaitu 10%, 20%, 30%, 40%, dan 50% serta 0% sebagai pembanding. Benda uji yang digunakan untuk pengujian kuat tarik belah berupa silinder berukuran diameter 15 cm x tinggi 30 cm, pengujian kuat tarik lentur berupa balok berukuran 60 cm x 15 cm x 15 cm, dan pengujian kuat geser murni berupa prisma berukuran 30 cm x 30 cm x 10 cm. Diameter agregat maksimum yang digunakan adalah 12 mm. Faktor air semen yang digunakan adalah 0,3. Dalam campuran beton ditambahkan superplasticizer sebanyak 1,5% dari berat semen. Hasil penelitian menunjukkan bahwa kuat tarik belah maksimum didapat pada variasi substitsi pasir pozzolan 10% yaitu sebesar 6,25 MPa dengan selisih 26,11% dari kuat tarik belah beton pembanding (0%) yaitu sebesar 4,96 MPa. Hasil pengujian kuat tarik lentur maksimum terjadi pada variasi yang sama yaitu 10% sebesar 6,49 MPa dengan selisih 25,97% dari kuat tarik belah beton pembanding yaitu sebesar 5,15 MPa. Selanjutnya, hasil pengujian kuat geser murni maksimum diperoleh nilai 5,39 MPa dari variasi 10% dengan selisih 2,75% dari kuat geser murni beton pembanding sebesar 5,25 MPa. dari hasil tersebut dapat disimpulkan bahwa penggunaan pasir pozzolan sebagai substitusi agregat halus direkomendasikan sebanyak 10%

An investigation of the beneficial effects of adding carbon nanotubes to standard injection grout

Mortar grouting is often used in masonry constructions to mitigate structural decay and repair damage by filling cracks and voids, resulting in an improvement in mechanical properties. This paper presents an original experimental investigation on grout with added carbon nanotubes (CNTs). The samples were prepared with different percentages of CNTs, up to 1.2 wt% with respect to the binder, and underwent three‐point bending tests in crack mouth opening displacement mode and compressive tests. The results showed that very small additions (up to 0.12 wt% of CNTs) increased not only flexural and compressive strengths (+73% and 35%, respectively, in comparison with plain mortar) but also fracture energy (+80%). These results can be explained on the basis of a reduction in porosity, as evidenced by mercury intrusion porosimetry, as well as by a crack bridging mechanism and by the probable formation of nucleation sites for hydration products, as observed through scanning electron microscopy

Potential of Orange Peel Ash as a Cement Replacement Material

The potential of Orange peel ash (OPA) as a cement replacement material was investigated with focus on the effect of OPA content on the physicomechnical properties such as consistency, setting times, soundness, compressive and flexural strengths of OPA-cement blend for cement replacement between 2.5-10% at 2.5% interval. The optimal calcination temperature and time of orange peel (OP) was achieved by calcining the OP at various temperature between (600 °C, 700 °C, 800 °C) and time (1 hr. and 2 hrs.) respectively. The chemical compositions of the various orange peel ashes were determined using X-ray fluorescence equipment and the optimal conditions was obtained at 600 °C and 2 hours. The consistency and setting time tests were conducted with a Vicat apparatus on the binary cement pastes in accordance to ASTM standards. Results indicated an increase in the water required for consistency as the OPA content was increased from 2.5-10 % which was attributed to the unburnt carbon content present in the ash. Similarly, a gradual increase in the cement replacement with OPA resulted in a prolonged setting time which was could be attributed to the diminution of the clinker content and the higher water requirement for normal consistence. The soundness of the OPA cement blend experienced an increase in free lime content as the OPA content rose from 2.5-10 %. Both compressive and flexural strengths were found to decrease as the OPA content was gradually increased whereas an increase in the strengths were observed as the curing days progressed. It was also observed that 5% cement replacement with OPA did not adversely affect the strength in comparison to the OPC control due to the pozzolanic reaction which resulted in the enhanced strengths especially at 28 days

Zeolita, estudio de aptitud como una puzolana natural aplicada a hormigón estructural

Nowadays, concrete is one of the most widely used construction materials due to its low price, appropriate mechanic characteristics and durability. Also, due to its ease to adopt diverse forms and sizes (Najimi et al., 2012). Owing to the importance in the use of concrete as a structural material and to its impact in the environment as a consumer of great quantities of natural resources and emitter of CO2 in the concrete industry, it is necessary to develop, from the science of materials, mixtures that support the growth of the construction industry and that consider the environment. Therefore, it becomes necessary to develop energetically efficient materials. A natural zeolite was studied as a material with potential pozzolanic activity and as partial replacement in different percentages of Portland cement in structural concrete. The results of the mechanic trials in concrete samples prove the feasibility of using this element as pozzolanic material.En la actualidad, el hormigón es uno de los materiales de construcción más ampliamente utilizados debido a su bajo precio, apropiadas características mecánicas y de durabilidad, así como por su facilidad de adoptar diversas formas y tamaños (Najimi et al., 2012). Debido a la importancia del uso del hormigón como material estructural de construcción y a su impacto ambiental como consumidor de grandes cantidades de recursos naturales y emisor de CO2 en la industria del cemento, es necesario desarrollar, desde la ciencia de materiales, mezclas que acompañen el crecimiento de la industria de la construcción considerando el medioambiente; es decir, desarrollar materiales energéticamente eficientes. Se estudió una zeolita natural como un material con potencial actividad puzolánica y como reemplazo parcial en distintos porcentajes del cemento pórtland en hormigones estructurales. Los resultados de ensayos mecánicos en hormigones evidencian la factibilidad de utilizar esta adición como material puzolánico.Fil: Raggiotti, Barbara Belen. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Grupo de Investigación En Tecnologías de Materiales y Calidad; ArgentinaFil: Positieri, María Josefina. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Grupo de Investigación En Tecnologías de Materiales y Calidad; ArgentinaFil: Locati, Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Murra, Juan Alberto Félix. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; ArgentinaFil: Marfil, Silvina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Ciencias de la Tierra. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Centro de Investigaciones en Ciencias de la Tierra; Argentin

Soluble pozzolanic materials from coal bottom ash as cement replacement material

Nowadays, intensive research in production of highly reactive pozzolanic materials from industrial waste to replace cement is crucial. This action expected to increase industrial waste recycling rate and at the same time reduce extraction of non-renewable resources of limestone. Unique characteristics of coal bottom ash as one of the industrial based pozzolan gained less popularity because of its low reactivity and heavy metal leaching due to conventional method used for disposal. Therefore, an alternative approach was deliberated in this research to utilize coal bottom ash into soluble form and enhance the quality of bottom ash as pozzolanic material. Coal bottom ash after the acid washing with optimum parameter was then undergoes solution-gelification process with various alkali based solution for 2 hours soaking durations. The conversion of coal bottom ash into soluble silica in this study demonstrates good pozzolanic performance in a state of siliceous gel pozzolan compared to the raw ones. 5% of cement replacement by soluble silica from CBA shows good strength development from early and later age. The physical dispersion effect is the cumulative effect of enhancement cement hydration due to the availability of increased the nucleation sites on soluble silica particles