Effect of Fineness of Basaltic Volcanic Ash on Pozzolanic Reactivity, ASR Expansion and Drying Shrinkage of Blended Cement Mortars (original) (raw)
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Crystals, 2022
The aim of this study was to investigate the influence of fineness and heat-treatment on the pozzolanic and engineering properties of volcanic ash. To this end, two different fineness levels of volcanic ash, ultra-fine (VAF) and fine (VA), without and after heat treatment at different temperatures (VA550, VA650, and VA750), were partially substituted for cement. In addition to the control (100% cement), five binary mortar mixes, each containing 20% of the different types of volcanic ash (VAF and VA; heat-treated and not), were prepared. First, X-ray fluorescence (XRF), X-ray powder diffraction (XRD), particle size analysis, and modified Chappelle tests were used to characterize the material. All mortar mixes were then tested for compressive strength development, water absorption, and apparent porosity. Finally, the microstructure of each of the mixes was evaluated by performing XRD, thermogravimetric analysis (TGA), and Fourier transform infrared spectroscopy (FTIR) analyses on past...
The Effects Of Volcanic Ash On The Strength And Permeability Mortar
2018
Cement replacement materials have been widely used to reduce adverse environmental impacts, increase the strength and durability of concrete, such as fume silica, slag, fly ash or natural pozzolan (volcanic ash). Volcanic ash is material that released from the earth when volcanic eruptions occur. Volcanic ash becomes an important environmental issue because it disturbs the balance of the environment. Volcanic ash is a very fine pyroclastic material, has a characteristic form of diversity. In the field of engineering, the usage of volcanic ash as added ingredients is still very limited, while active volcanoes emit volcanic ash every year. The purpose of this study is to determine the effect of added materials-volcanic ash of Dukono mountain to the mortar mixture. In this research, the test of compressive strength and mortar absorption. This research uses added materialvolcanic ash from Dukono mountain. Preparation of test specimens with FAS value 0.4 with volcanic ash composition 0%,...
Materials
This present study evaluates the effect of silica modulus (Ms) and curing temperature on strengths and the microstructures of binary blended alkali-activated volcanic ash and limestone powder mortar. Mortar samples were prepared using mass ratio of combined Na2SiO3(aq)/10 M NaOH(aq) of 0.5 to 1.5 at an interval of 0.25, corresponding to Ms of 0.52, 0.72, 0.89, 1.05 and 1.18, respectively, and sole 10 M NaOH(aq). Samples were then subjected to ambient room temperature, and the oven-cured temperature was maintained from 45 to 90 °C at an interval of 15 °C for 24 h. The maximum achievable 28-day strength was 27 MPa at Ms value of 0.89 cured at 75 °C. Samples synthesised with the sole 10 M NaOH(aq) activator resulted in a binder with a low 28-day compressive strength (15 MPa) compared to combined usage of Na2SiO3(aq)/10 M NaOH(aq) activators. Results further revealed that curing at low temperatures (25 °C to 45 °C) does not favour strength development, whereas higher curing temperature ...
2018
Volcanic Ash is one of naturally occurring Pozzolanaic material that was tested in this research work for partial replacement of cement for production of concrete. With respect to reduction of cement consumption for sustainable construction (i.e. reducing GHG emission) evaluation of the strength reduction is crucial as it has a severe impact on the structure under construction. This paper examines the effects of replacing cement by using Lege-Dadi Volcanic Ash on the strength and certain durability characteristics of concrete. The research aims to determine the optimal amount of Volcanic Ash for production of high-grade concrete. Preliminary tests of the different properties of materials used for this research were carried out. The Lege Dadi Volcanic Ash satisfied the requirement of ASTM C618-00.The samples of Volcanic Ash were prepared in five different proportions (0, 5, 10, 15 & 20 wt %) and design mix ratio of 1: 2.9: 3.9 with a 0.61 w/c ratio to make 45 cubic and 27 cylindrical...
The increasing cost and scarcity of portland cement has impacted negatively on the delivery of affordable housing and infrastructural development in many parts in Sudan, especially in Darfur. This paper focused on the evaluation of the pozzolanic characteristics of the volcanic ash obtained from Jebel Marra (mountains) west of Sudan as potential Supplementary Cementitious Materials for use in blended cement and concrete. The study investigated the chemical, physical, and mineralogical characteristics of the volcanic ash and its reactivity toward lime and cement, in addition , the compressive strengths of blended mortar containing volcanic ash in percentage addition were tested at 7, 28, and 90 days. X-Ray Fluorescence and X-ray diffraction techniques were used for chemical and mineralogical analysis respectively. The results of the chemical analysis showed that the sum oxides of Silica, Alumina and Iron were 83.75%. The strength reactivity with lime was 4.2Mpa, while the 28-days compressive strengths for the replacement level with cement 10%, 20%, 30%, 40%, and 50% were 38.9, 35, 29.33, 28.64, and 25 Mpa respectively, against 41.33Mpa., for the control mix. These results indicated that the Jebel Marra Volcanic Ash possesses pozzolanic characteristics and is thus potential cementitious material for use in blended cement.
Path of Science
An increase in the generation of biogenic wastes such as locust bean pods and eggshells coupled with the need to drive sustainability in the cement industry has led the use of these wastes as cement replacement materials. The paper aims to investigate the effect of locust bean pod ash (LBPA) and eggshell ash (ESA) on the mortar compressive and flexural strength of ternary cement blends. The LBPA was obtained by calcining locust bean pod (LBP) at various temperatures of 800-900 °C and time of 60-120 minutes at an interval of 50 °C and 30 minutes respectively to determine the optimal conditions. The chemical composition of Ordinary Portland cement (OPC), LBPA and ESA were obtained via X-ray Fluorescence (XRF) Spectrometer and LBPA chemical composition did not satisfy one of the requirements specified by ASTM C618-01 (2001) with SiO 2 + Al 2 O 3 +Fe 2 O 3 of 30.42 wt. % which is less than 50 wt. %, but satisfies SO 3 content requirement of 0.7 wt. % and Loss on Ignition (LOI) of 7.12 wt. % and contains 19.42 wt. % CaO which is within the range of 10-30 wt. % CaO is class C pozzolan. The compressive strength of blended cement mortars at the early age of 2 and 7 days produced better strengths for cement blends with higher ESA content than LBPA especially at LBPA/LBPA-ESA ratio of 0, 0.4 and 0.6 for 2.5 wt. % cement replacement respectively. The early strength gain could be attributed to the provision of more nucleation sites by ESA inclusion which results in the acceleration of cement hydration rate. On the other hand, the enhanced strengths at 28 days of cement blended with various replacement from 2.5-10 wt. % could be attributed to the pozzolanic reaction between the available lime and reactive silica from LBPA despite clinker diminution which was close to control. Another reason for enhanced strength' could be attributed to the increased potassium content by an increase in LBPA content resulting in a gradual strength gain (retarder) muscovite formation K 2 Al 2 Si 6 Al 4 O 20 (OH) 4. All cement blends experienced an increase in the mortar compressive and flexural strengths as the curing day progressed with some blends producing enhanced strength compared to control especially with 1.5 ESA1LBPA produced the best strength at 50.15 (6.82) N/mm 2 against 48.80 (6.80) N/mm 2. This enhanced strength could be related to the pozzolanic activity and the high potassium content from LBPA despite clinker diminution, especially at 28 days.
Pozzolanic Characteristics of a Natural Raw Material for Use in Blended Cements
2009
In this study, the potential use of a natural raw material in the manufacture of blended cements was investigated. Mineralogical, petrographic and chemical analyses of the samples showed that the natural raw material was a porphyritic volcanic rock close to trachyandesite composition with a SiO 2 +Al 2 O 3 +Fe 2 O 3 content of 79.86%. Further experiments were also designed to determine the physical properties and pozzolanic activity of the raw material. The mortar samples, made with a binder of ground trachyandesite and lime, developed compressive and flexural strengths of 2.5 and 3.3 times respectively higher than those required for a natural pozzolan. Further tests revealed that when the ground trachyandesite replaced 30% w/w of Portland cement, the blended cements produced had the desired physical and chemical characteristics with compressive strengths higher than 32.9 N/mm 2 . These findings suggest that this material can be used in the production of blended cements.
Effect of basalt powder addition on properties of mortar
MATEC Web of Conferences
The study evaluates the use of waste basalt powder as a replacement of cement to enhance hydration of cement and mortar properties. The basalt powder is a waste resulting from preparation of aggregate used in asphalt mixture production. Previous studies have shown that analysed waste used as a fine aggregate replacement has a beneficial effect on some properties of mortar and concrete, i.e. compressive strength, flexural strength and freeze resistance. The present study shows the results of the research concerning the modification of cement paste and mortar with basalt powder. The modification consists in adding the powder waste as a partial replacement of cement. The percentages of basalt powder in this research are 0-40% and 0-20% by mass of cement in the pastes and mortars respectively. The experiments were carried out to determine the influence of basalt powder on cement hydration, as well as compressive and flexural strength. Results indicate that addition of basalt powder as a...