scholarly journals Behavior of green reactive powder mortar reinforced with steel fibers

2021 ◽  
Vol 30 (1) ◽  
pp. 130-143
Author(s):  
Eethar Thanon Dawood ◽  
Mafaz Hani Abdullah

Abstract The use of supplementary cementitious materials like crushed glass, steel slag, and silica fume at an acceptable level has resulted in many advantages such as reduction of the waste solid materials and production of eco-friendly material. Moreover, the inclusion of fibers for reinforcing cementitious matrix can improve its properties overall. Therefore, this research has been divided into two phases. The first phase has included the production of green reactive powder mortar and the investigation of its properties. The second phase has involved the incorporation of the micro steel fibers to green reactive powder mortar with different amounts. The results have indicated that the use of the crushed glass, steel slag, and silica fume by 8, 12, and 10% as a partial replacement of cement with suitable chemical admixture gives a great reduction of cement by 30% from the total cementitious amount used in reactive powder mortar and greater values of strengths for reactive powder mortar. The addition of micro steel fibers by 1, 1.5, 2, and 2.5% improves the dry bulk density, ultrasonic pulse velocity, compressive strength, flexural strength, and tensile strength of green mortar. The best increase has been observed at green reactive powder mortar (GRPC) containing 2 % of micro steel fibers.

2021 ◽  
Vol 877 (1) ◽  
pp. 012045
Author(s):  
Raid Hussian

Abstract Cement is amongst the most polluting materials utilized in the building sector, contributing to a variety of hazardous pollutants, including greenhouse gas emissions. This raises health impacts related to the manufacture of cement. As a result, a substitute substance for conventional cement with low environmental effects and better building characteristics is required. The purpose of the study would be to look at the consequences of using supplementary cementitious materials (SCMS) to substitute cement in a concrete mix partially. This study employed silica fume (SF) and cement kiln dust (CKD) as supplementary cementitious materials. Several concrete mixtures were created by substituting cement by a combination of SF and CKD in three proportions which that 25%, 35%, and 45% within curing periods of (one week and four weeks); the concrete mixtures were tested. The ultrasonic pulse velocity (UPV) test has been used to investigate the concrete mixture’s strength in this study. The findings show that the optimal proportion of SF replacement cement and CKD involvement ranged from 25% to 35%. The pulse velocity of specimens improves when the proportion of CKD and SF increases to the optimal percentage, while the larger amounts of these by-products begin to lower the pulse velocity of specimens.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Hongxia Qiao ◽  
Desire Ndahirwa ◽  
Yuanke Li ◽  
Jinke Liang

The research gap about the application of basalt rock powder (BRP) and superfine sand (SS) as fillers in preparation of cement mortar is significant. This study characterizes the mechanical performance of the cement mortar formulated considering Portland cement, artificial sand and water as principal mixture components. To analyze the influence of BRP and SS on the strength properties of the mortar, the Portland cement and artificial sand have been replaced by BRP and SS respectively. The replacement percentages are 10%, 15%, 20%, 25% and 30% when the basalt rock powder replaces Portland cement and in case artificial sand is replaced by superfine sand, 10%, 20%, 30%, 40% and 50%. The percentages of basalt rock powder and superfine sand replace, in volume, the same quantity of Portland cement and artificial sand that forms portion of the mixture. The strength indexes such as flexural strength, compressive strength, ultrasonic pulse velocity and dynamic elastic modulus were investigated. Overall results show that despite the reduction of mechanical properties of cement mortar, BRP and SS can be used as partial replacement of Portland cement and artificial sand in account of ratios from 10% to 25% basalt rock powder quantity by Portland cement weight and 10% to 20% superfine sand amount by volume of artificial sand.


2019 ◽  
Vol 10 (3) ◽  
pp. 253-258
Author(s):  
S. Jagan

Sustainability and scarcity in resources are the two major issues to be dealt within the present scenario by effective utilization of alternative materials. In this present study, an attempt has been taken to study the effect of supplementary materials such as fly ash and silica fume as a partial replacement to cement and steel slag and M-sand as a replacement to river sand on strength and durability of concrete. In this study, concrete specimens were prepared based on five different mixes by varying the percentages of these supplementary materials. Various mechanical properties like compressive strength, split tensile strength and flexural strength were performed to ascertain the mix with optimum levels of replacement of supplementary materials for cement and fine aggregate. Durability property like water absorption test was performed on the mix with optimum values of strength. Results revealed that mix with higher percentages of steel slag, optimum level of silica fume and fly ash have shown higher strength and lesser permeability in concrete.


Author(s):  
Mohammed S. Nasr ◽  
Zaid A. Hasan ◽  
Mohammed K. Abed ◽  
Mohammed K. Dhahir ◽  
Wissam N. Najim ◽  
...  

The reactive powder concrete (RPC) is one of the special concrete types that characteristics with high cement content which means high production cost and CO2 emissions to the atmosphere. Therefore, to enhance the environment as well as to develop green RPC, alternatives to cement, such as supplementary cementitious materials (SCMs) were used. Limited studies addressed the use of a high volume fraction of SCMs as a binary combination in the production of RPC. Thus, this study aims to replace a high percentage of cement (50%) with binary combinations of silica fume (SF), type F fly ash (FA) and metakaolin (MK). The experimental program included two phases. In phase one, two groups (SF+FA and MK+FA) were cast without steel fibers. Based on group performance in the first phase, one group was chosen to be used with steel fibers in the second phase. The flow rate, compressive and flexural strengths, density, ultrasonic pulse velocity and dynamic modulus of elasticity tests were conducted. The phase one results showed that SF+FA combination mixtures had better performance than MK+FA mixtures thus they were selected to be used in the second phase (with the addition of 1% volumetric fraction micro steel fibers). Results indicated that it is possible to produce sustainable RPC in which the cement can be replaced with 30% SF and 20% FA (the total replacement is 50%) in the presence of 1% steel fibers with a remarkable enhancement in compressive strength and flexural strength reached up to 44% and 10%, respectively.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
V. M. Sounthararajan ◽  
A. Sivakumar

Investigations on the different supplementary cementitious materials based on the hardening properties and the optimized dosage in cementitious systems find the right choice of pozzolanic material. It is essential to combine various additive/admixtures in concrete in proper proportions to maximize the benefits resulting in cost savings in construction. In the recent years, production technology and composition of hydraulic cements affect the setting and early age behavior of cementitious material. The addition of fly ash in cement is one viable technology to derive maximum benefits in terms of the economy and improved pozzolanic reaction. Ultrasonic pulse velocity testing is a feasible method for evaluating the hardening properties of cementitious materials. In this study, an attempt was made to derive the engineering basis for understanding the development of hardness during hydration of fly ash (FA) based cementitious systems. The tests conducted using pulse velocity technique proved to be an effective method for characterizing the early strength gain properties of different cementitious systems.


Carbonation is one of the imperative properties that affect the durability of concrete especially in case of reinforced structures. In this present study, an attempt has been taken to study the effect of M sand and other supplementary cementitious materials like silica fume, fly ash and steel slag as a partial replacement to cement. Different combinations with M sand, river sand and combinations of M sand and river sand with supplementary cementitious materials at water to cement ratio varying from 0.45 to 0.5 was studied. Results revealed that the complete replacement of river sand by M sand reduced the rate of carbonation but addition of supplementary cementitious along with either river sand or M sand resulted in increase over the rate of carbonation compared to conventional concrete.


Author(s):  
Eethar Dawood ◽  
Mafaz Abdullah

The various green mortar mixes have been used in this study using various percentages of waste glass powder (WGP), steel slag (SG) and Micro-silica fume(SF).The different properties of flow, density, ultrasonic pulse velocity (UPV), compressive and flexural strengths have been tested for such green mortar in the  first phase of experimental work. The second phase deals with the regression analysis of such properties. Whereas, the analysis of the results have also been using the integrated AHP and TOPSIS methods for selection the best performance of the green mortar due to the ecological effects of such materials. The results showed that the use of 70%OPC+8%WGP+12%SG+10% SF indicated as the best performance in term of ecological impact compared with other mortar mixes. Also, the regression analysis using the integrated AHP and TOPSIS methods gives an effective strategy for the selection of the best mortar mix.


2021 ◽  
Vol 879 ◽  
pp. 100-114
Author(s):  
Izwan B. Johari ◽  
Md Azlin Md Said ◽  
Mohd Amirul B. Mohd Snin ◽  
Nur Farah Aqilah Bt. Ayob ◽  
Nur Syafiqah Bt. Jamaluddin ◽  
...  

This paper investigates the effect of partial replacement of fly ash with sago pith waste ash and silica fume in fabricating the geopolymer mortar concrete. The mixtures of geopolymer mortar concrete were prepared by replacing sago pith waste ash and silica fume at 5% of total weight of fly ash. There were six specimens of geopolymer mortar cubes and bricks fabricated in this study. The specimens are tested with compressive strength test, rebound hammer test and ultrasonic pulse velocity test. The results from the tests are compared with some existing published works as to clarify the effect of replacing the fly ash with sago waste and silica fume on the strength of concrete. Comparisons had been made and concluded that the molarity of alkaline solution, Al3O2 and CaO influenced the development of compressive strength along the curing time of fly ash based geopolymer concrete.


2021 ◽  
Vol 11 (9) ◽  
pp. 4028
Author(s):  
Asghar Gholizadeh Vayghan ◽  
Liesbeth Horckmans ◽  
Ruben Snellings ◽  
Arne Peys ◽  
Priscilla Teck ◽  
...  

This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al2O3 and CaO. The slags were treated at 1200–1300 °C (to reduce the heavy metal content) and then granulated in water to promote the formation of reactive phases. A full hydration study was carried out to assess the kinetics of reactions, the phases formed during hydration, the reactivity of the slags and their strength activity as supplementary cementitious material (SCM). The batch-leaching behaviour of cementitious mixtures incorporating treated slags was also investigated. The results showed that all three slags have satisfactory leaching behaviour and similar performance in terms of reactivity and contribution to the strength development. All slags were found to have mediocre reactivity and contribution to strength, especially at early ages. Nonetheless, they passed the minimum mechanical performance requirements and were found to qualify for use in cement.


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