Effect of using 3D-printed shell structure for reinforcement of ultra-high-performance concrete

This study aims to investigate the effect of 3D-printed polymer shell reinforcemen ton ultra-high-performance concrete. The mechanical properties of ultra-high-performance polymer reinforced concrete have been investigated. At first, the 3D-printed shell reinforcements were designed using 3D Max and Rhino 6 software. Then, each was fabricated through the fused deposition modeling method and positioned into the cubic, cylindrical, and prismatic molds. In the next step, the prepared Ultra-High-Performance Concrete mixture was poured into the molds, and the samples were cured for 28 days. Finally, the compressive, tensile, and flexural strength tests were carried out on the samples. The results indicated that the compressive, tensile, and flexural strengths of reinforced samples were lower than that of the unreinforced ones, respectively. Although including 3D-printed reinforcement decreased the mechanical properties of the Ultra-High-Performance Concrete samples, it changed the fracture mechanism of concrete from brittle to ductile

Effect of gelatin powder, almond shell, and recycled aggregates on chemical and mechanical properties of conventional concrete

The objective of the research is to study the effect of different additives on the conventional concrete. In this term, three types of materials have been added to the concrete: gelatin powder as the binder, recycled aggregates, and almond shell as the fine and coarse aggregates. Several experiments have been made tо determine physical and mechanical properties, such as test for compressive and tensile strengths, for impact loading strength, durability test (water absorption) and deep penetration tests. Moreover, the microstructure results for the new type of concrete have been studied by means of scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDXS). The results show that when 70 kg of gelatin powder is added to 1 m3 of concrete, the concrete’s compressive strength and tensile strength are improved more than 22%; during impact loading the first and ultimate cracks are 11 and 129 by numbers, and the first and ultimate cracks’ strength is more than 223 and 2346 J respectively. The durability of sample from concrete with additional gelatin has been improved. SEM results illustrate that the weakness of almond shell concrete is related to cracks and voids between the cement matrix and almond shell. The voids of gelatin concrete are higher than that of conventional concrete. The conventional concrete has smooth crystals, and gelatin concrete has sharp and cubic crystals. EDXS results show that chemical content of these two types of concrete is different: conventional concrete contains silicon, while EDXS results show that chemical content of these two types of concrete is different: conventional concrete contains silicon, while gelatin concrete contains calcium and also C-S-H gel is generated in it

Влияние порошка желатина, миндальной скорлупы и вторичных заполнителей на химические и механические свойства обычного бетона

The objective of the research is to study the effect of different additives on the conventional concrete. In this term, three types of materials have been added to the concrete: gelatin powder as the binder, recycled aggregates, and almond shell as the fine and coarse aggregates. Several experiments have been made tо determine physical and mechanical properties, such as test for compressive and tensile strengths, for impact loading strength, durability test (water absorption) and deep penetration tests. Moreover, the microstructure results for the new type of concrete have been studied by means of scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDXS). The results show that when 70 kg of gelatin powder is added to 1 m3 of concrete, the concrete’s compressive strength and tensile strength are improved more than 22%; during impact loading the first and ultimate cracks are 11 and 129 by numbers, and the first and ultimate cracks’ strength is more than 223 and 2346 J respectively. The durability of sample from concrete with additional gelatin has been improved. SEM results illustrate that the weakness of almond shell concrete is related to cracks and voids between the cement matrix and almond shell. The voids of gelatin concrete are higher than that of conventional concrete. The conventional concrete has smooth crystals, and gelatin concrete has sharp and cubic crystals. EDXS results show that chemical content of these two types of concrete is different: conventional concrete contains silicon, while EDXS results show that chemical content of these two types of concrete is different: conventional concrete contains silicon, while gelatin concrete contains calcium and also C-S-H gel is generated in it.Цель исследования - определить влияние различных добавок на свойства обычного бетона. В бетонную смесь внесены три вида добавок: желатиновый порошок в качестве связующего, вторичные заполнители и миндальная скорлупа в качестве мелкого и крупного заполнителей. Проведено исследование по определению физико-механических свойств бетона с указанными добавками: прочности на сжатие и растяжение, испытания на ударную нагрузку, на долговечность (водопоглощение) и на глубину проникновения влаги в бетон. Микроструктура бетона изучена с помощью сканирующей электронной микроскопии (SEM) и энергодисперсионной рентгеновской спектроскопии (EDXS). Установлено, что при добавлении 70 кг желатинового порошка на 1 м3 бетона его прочность на сжатие и растяжение увеличилась более чем на 22 %; под действием ударной нагрузки начальное и предельное количество трещин составляет 11 и 129, а начальная и предельная прочность трещинообразования - более 223 и 2346 Дж соответственно. Кроме того, показатели долговечности лучше у бетона с добавлением желатина. Результаты, полученные при помощи SEM, демонстрируют, что пониженная прочность бетона с добавлением миндальной скорлупы связана с трещинами и пустотами между цементной матрицей и миндальной скорлупой. Пустоты в бетоне с желатином выше, чем в обычном бетоне. Структура обычного бетона имеет вид гладких кристаллов, а бетона с желатином - острые и кубические кристаллы. Результаты, полученные с помощью EDXS, показали различие в химическом составе: обычный бетон содержит кремний, тогда как бетон с добавкой желатина в вышеуказанных пропорциях содержит кальций и в нем образуется гель C-S-H

Finite Element Analysis of Self-Healing Concrete Beams Using Bacteria

Deterioration or crack formation in concrete elements is a phenomenon that cannot be easily avoided, and it has a high cost of repair. A modern technology that needs wider study is the use of the bio-precipitation of calcium carbonate using bacteria to increase a structures’ capacity. The current research presents an analytical study on self-healing concrete beams using bacteria to enhance the beam’s capacity. A Finite Element Analysis on (ANSYS 15.0) was carried out to study the effect of the bacteria concentration (the weight of bacteria to cement weight 1%, 2%, and 3%), the type of bacteria (Bacillus subtilis, E. coli, and Pseudomonas sps.), and the loading (a one-point load, a two-point load, and a distributed load on four points) on concrete beams. Two beams were chosen from previous experimental research and simulated on the ANSYS before carrying out our parametric study to verify the validity of our simulation. Following this, our parametric study was carried out on eight beams; each beam was loaded gradually up to failure. The results show that the optimum type of bacteria was the Bacillus subtilis, and that the bacteria concentration of 3% for Bacillus subtilis can increase the beam’s capacity by 20.2%. Also, we found that distributing the load to four points led to the increase of the beam’s capacity by 74.5% more than the beam with a one-point load

Experimental Investigation and Image Processing to Predict the Properties of Concrete with the Addition of Nano Silica and Rice Husk Ash

The use of the combination of ultrafine rice husk ash (RHA) and nano silica (NS) enhances the compactness of hardened concrete, but there is still a lack of studies that address the effects of NS and RHA on the workability, mechanical properties and pore microstructure of concrete. This study mainly aims to investigate the influence of the pore size distribution in multiphysics concrete model modified by NS and RHA and to determine the workability and mechanical properties of concrete with NS and RHA. In this work, NS and RHA were used as 0, 5, 10, 15 and 20% replacements of ordinary Portland cement (OPC) in concrete grade M20. Concrete mixed with NS and RHA showed improved performance for up to 10% addition of NS and RHA. Further addition of NS and RHA showed a decrease in performance at 7, 14 and 28 days. The decrease in concrete porosity was also found to be up to 10% when adding NS and RHA to cement. Image processing was performed on the cement-based materials to describe the microstructure of the targeted material without damage. The results from the experimental and tomography images were utilized to investigate the concrete microstructure and predict its inner properties.Applied Science, Faculty ofNon UBCCivil Engineering, Department ofReviewedFacult

Structure and Content Analysis of Raw Materials for Production of Trimanganese Tetraoxide Pigment

The research aims to reveal the structure, phase, and elemental content of manganese ores from deposits—Bogach (Karaganda region, Kazakhstan) and Zhaksy (Akmola region, Kazakhstan). The samples were studied with scanning electron microscopy with energy dispersive analysis (SEM-EDA), X-ray diffractometry (XRD), Infra-red spectroscopy (IRS). During the research, structural peculiarities, elemental and phase content of the samples have been revealed. The mineral matter of the Bogach deposit ore mainly consists of hollandite, cryptomelane, braunite, calcite, bixbyite, quartz. The Zhaksy deposit ore includes quartz, hollandite, bixbyite, pyrolusite. Bogach ore includes (wt.%) C(10.68), O(32.00), Mn(43.26), Ca(6.36), Si(3.51), Na(0.52), Al(1.13), Mg(0.69), K(1.85). The elemental content of Mn in Zhaksy ore is two times lower. Zhaksy ore includes (wt.%) C(23.77), O(32.1), Mn(21.81), Si(10.52), Al(5.13), K(1.21), Fe(5.47). The obtained data of the conducted spectral analysis indicate that both samples represent a polymineral heterogeneous structure. Conducted research allows to conclude, that by phase-elemental content the Bogach ore can be used for obtaining trimanganese tetraoxide pigment similar to manganese ores from West Sumatera deposit (Indonesia) by top-down method using grinding with a milling tool and high-temperature sintering