Comparative study of stabilization/solidification of dredged sediments with ordinary Portland cement and calcium sulfo-aluminate cement in the framework of valorization in road construction material

2021 ◽  
Vol 279 ◽  
pp. 122447
Author(s):  
Rachid Zentar ◽  
Hongwei Wang ◽  
Dongxing Wang
Keyword(s):  
Comparative Study ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Construction Material ◽  
Road Construction ◽  
Dredged Sediments ◽  
Aluminate Cement

scholarly journals Utilization of Sugarcane Bagasse Ash from Power Co-generation Boilers as a Supplementary Cementitious Material

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Safiki Ainomugisha ◽  
Bisaso Edwin ◽  
Bazairwe Annet
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Sugarcane Bagasse ◽  
Low Income ◽  
Ordinary Portland Cement ◽  
Construction Material ◽  
Sustainable Construction ◽  
Partial Replacement ◽  
Hardened Concrete ◽  
Sugarcane Bagasse Ash

Concrete has been the world’s most consumed construction material, with over 10 billion tons of concrete annually. This is mainly due to its excellent mechanical and durability properties plus high mouldability. However, one of its major constituents; Ordinary Portland Cement is reported to be expensive and unaffordable by most low-income earners. Its production contributes about 5%–8% of global CO2 greenhouse emissions. This is most likely to increase exponentially with the demand of Ordinary Portland Cement estimated to rise by 200%, reaching 6000 million tons/year by 2050.  Therefore, different countries are aiming at finding alternative sustainable construction materials that are more affordable and offer greener options reducing reliance on non-renewable sources. Therefore, this study aimed at assessing the possibility of utilizing sugarcane bagasse ash from co-generation in sugar factories as supplementary material in concrete. Physical and chemical properties of this sugarcane bagasse ash were obtained plus physical and mechanical properties of fresh and hardened concrete made with partial replacement of Ordinary Portland Cement. Cost-benefit analysis of concrete was also assessed. The study was carried using 63 concrete cubes of size 150cm3 with water absorption studied as per BS 1881-122; slump test to BS 1881-102; and compressive strength and density of concrete according to BS 1881-116. The cement binder was replaced with sugarcane bagasse ash 0%, 5%, 10%, 15%, 20%, 25% and 30% by proportion of weight. Results showed the bulk density of sugarcane bagasse ash at 474.33kg/m3, the specific gravity of 1.81, and 65% of bagasse ash has a particle size of less than 0.28mm. Chemically, sugarcane bagasse ash contained SiO2, Fe2O3, and Al2O3 at 63.59%, 3.39%, and 5.66% respectively. A 10% replacement of cement gave optimum compressive strength of 26.17MPa. This 10% replacement demonstrated a cost saving of 5.65% compared with conventional concrete. 

An Experimental Evaluation of Development Length of Reinforcements Embedded in Geopolymer Concrete

2014 ◽  
Vol 578-579 ◽  
pp. 441-444 ◽  
Author(s):  
Jee Sang Kim ◽  
Jongho Park
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Construction Material ◽  
Geopolymer Concrete ◽  
Development Length ◽  
Reinforcing Bars ◽  
Bond Slip ◽  
Ordinary Concrete ◽  
Pull Out

Geopolymer concrete is an emerging construction material that uses a by-product material such as fly ash to completely replace the ordinary Portland cement. This material is being studied extensively and shows promise as a greener substitute for ordinary Portland cement. This paper evaluates the bond strength and development length of reinforcements embedded in geopolymer concrete with reinforcing steel using pull-out tests. The test according to EN 10080 was carried out on 27 specimens for three kinds of geopolymer concrete of 20, 30 and 40 MPa compressive strength and 10, 16 and 35 mm diameter reinforcing bars. The tests show that the bond strengths in geopolymer concrete were decreased as the diameter of reinforcement increased as in ordinary concrete and the values were greater than those in ordinary concrete. Also, the bond-slip curves were obtained which have similar shape with those of ordinary concrete. The equation for the determination of development length based on this experiment was proposed.

scholarly journals Calcium aluminate cement as an alternative to ordinary Portland cement for the remediation of heavy metals contaminated soil: mechanisms and performance

2021 ◽  
Vol 21 (4) ◽  
pp. 1755-1768
Author(s):  
Loris Calgaro ◽  
Silvia Contessi ◽  
Alessandro Bonetto ◽  
Elena Badetti ◽  
Giorgio Ferrari ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Portland Cement ◽  
Granular Materials ◽  
Calcium Aluminate ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Ordinary Portland Cement ◽  
Retention Mechanism ◽  
Calcium Aluminate Cement ◽  
Aluminate Cement

Abstract Purpose This work deals with the application of a solidification/stabilization process with the aim to obtain safe and reusable granular materials from a polluted soil and to elucidate the mechanisms involved in the retention of several heavy metals. Materials and methods The High Performance Solidification/Stabilization (HPSS®) process was applied to the selected contaminated soil by using both ordinary Portland cement and calcium aluminate cement, as well as several binders prepared by combining these two types of cement in different proportions. Leaching and mechanical tests were carried out to evaluate the performances of the proposed binders in the pellets produced by the HPSS® process, while XRD analysis and SEM/EDX imaging were used to investigate the phase composition and internal microstructure of the treated samples. Result and discussion The examination of the obtained granular materials revealed that the immobilization of Sb was mainly related to its inclusion within calcium silicate hydrates’ structure; the immobilization of Cr, Pb, Ni, Co, Zn and Tl was associated with the eluate pH and their incorporation within ettringite structure, while for Se, Cu, Ba and V, the main retention mechanism was physical encapsulation. In addition, the application of a wet conditioning process improved the materials’ performance, leading to granules always satisfying the Italian regulatory requirements for reuse. Conclusions The findings obtained in this study were useful to better elucidate the mechanisms involved in the retention of heavy metals by several binders, contributing to the development of sustainable management strategies for contaminated soils and sediments through their transformation into reusable materials. Graphical abstract

The Effect of Nanoparticles of Ordinary Portland Cement (OPC) on Compressive Strength of Concrete

2014 ◽  
Vol 894 ◽  
pp. 342-348
Author(s):  
Abdoullah Namdar ◽  
Fadzil Mat Yahaya
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Construction Material ◽  
Simple Method ◽  
X Ray ◽  
Compressive Strength Of Concrete ◽  
Stability Of Structure ◽  
Scanning Electron

The quality of a construction material satisfies stability of structure. Several additives have been innovated for improve quality of compressive strength of concrete. In this paper for enhancement of compressive strength of concrete, a simple method has been proposed. The kaolin and bentonite have been treated by heat for duration of 1 hour, with constant temperature. For kaolin 200 oC, 400 oC, 600 oC, 800 oC, 1000 oC and 1200 oC of heat, and for bentonite 200 oC, 400 oC, 600 oC, 800 oC of heat has been subjected. The kaolin and bentonite treated by heat have been proposed as additive for concrete. The objective is to introduce an additive to improve compressive strength of concrete. The microstructure of modified Ordinary Portland Cement (OPC) paste has been investigated by using Field Emission Scanning Electron Microscopy (FESEM) and X-ray diffractometry (XRD). The results indicate that the best level of heat for produce additives from kaolin and bentonite, and illustrate quantity of additives for replace a portion of cement in concrete application. Modification of nanoparticles of cement paste during hydration has been discussed.

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