scholarly journals Hydrothermally-calcined waste paper ash nanomaterial as an alternative to cement for clay soil modification for building purposes

2021 ◽  
Vol 61 (6) ◽  
pp. 749-761
Author(s):  
Ubong Williams Robert ◽  
Sunday Edet Etuk ◽  
Okechukwu Ebuka Agbasi ◽  
Grace Peter Umoren ◽  
Samuel Sunday Akpan ◽  
...  
Keyword(s):  
Public Health ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Clay Soil ◽  
Building Design ◽  
Waste Paper ◽  
Clay Material ◽  
Environment And Public Health ◽  
Portland Limestone Cement ◽  
Limestone Cement

It has been observed that clay soil cannot be used for building design, unless it is modified by firing or with cement. Either method of stabilization can adversely affect the environment and public health just like indiscriminate dumping or open burning adopted in developing countries as the prevalent disposal technique for waste papers. This paper sought to examine the feasibility of using assorted waste papers to derive an alternative stabilizer to Portland Limestone Cement for modification of clay soil into composite materials suitable for building design. Specifically, clay-based composites were fabricated at 0 %, 5 %, 10 %, 15 %, and 20% replacement levels by weight with cement, and then hydrothermally-calcined waste paper ash nanomaterial (HCWPAN). Water absorption, sorptivity, bulk density, thermal conductivity, specific heat capacity, thermal diffusivity, flaking concentration, flexural strength, and compressive strength were investigated for each of the fabricated samples. Irrespective of the stabilizing agent utilized, 10% loading level was found to be the optimum for possession of maximum mechanical strength by the samples. Only samples with the HCWPAN content were found to be capable of reducing building dead loads and improving thermal insulation efficiency over un-stabilized clay material, if applied as walling elements in buildings. Generally, it was revealed that the cement and HCWPAN have comparable influences on the properties of clay soil, thus indicating that HCWPAN could be utilized as an alternative stabilizer to cement. In addition, the preparation of HCWPAN was found to be more energy-saving than that of the cement.

scholarly journals Development of an Eco-material Based on Palmyra Aggregates

2020 ◽  
pp. 83-96
Author(s):  
Valéry K. Doko ◽  
Edem Chabi ◽  
Sena Peace Hounkpè ◽  
Edmond C. Adjovi
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Thermal Characteristics ◽  
Cement Matrix ◽  
Compatibility Study ◽  
Flexural Tensile Strength ◽  
Portland Limestone Cement ◽  
Previously Treated ◽  
Limestone Cement ◽  
Mechanical Strengths

This study is part of a project to develop a bio-based material meeting the criteria of sustainable development in the field of construction. A study was then made on a cement matrix composite reinforced by aggregates of Borassus aethopium mart (palmyra). For this purpose, studies of cement compatibility with this plant aggregate, the physical, mechanical and thermal behavior of the concrete were performed for two granular compositions. The compatibility study revealed that palmyra aggregrates, although not previously treated, are compatible with Portland-limestone cement. The characterization tests focused on the mechanical properties of three-point flexural tensile strength and compressive strength and thermal properties such as effusivity, conductivity and diffusivity. The results obtained are promising: they have very good mechanical and thermal characteristics, considering its use in construction. The mechanical strengths reach 16.25 MPa for a density less than 1500 kg / m3. The thermal conductivity varies between 0.270 and 0.415. They can be used for the manufacture of panels used in the realization of suspended ceilings and tiles for the realization of roofs.

Sludge Disposal to Sea in South Africa

1982 ◽  
Vol 14 (3) ◽  
pp. 93-107 ◽  
Author(s):  
D C Macleod
Keyword(s):  
Public Health ◽  
South Africa ◽  
Marine Environment ◽  
Industrial Waste ◽  
Domestic Sewage ◽  
Monitoring Programme ◽  
Environment And Public Health ◽  
Research Project ◽  
Sludge Disposal ◽  
Sea Outfalls

The performance of two sea outfalls that have been in operation off the coast of Durban for over 10 years has been monitored for effects on the marine environment and public health. The discharge has been a mixture of domestic sewage and industrial waste from which a large proportion of the sludge has been removed but a 2-year research project, in which the balance of the sludge is also being discharged, has commenced. Performance of the outfalls and details of the monitoring programme are reviewed.

scholarly journals Influence of alkaline modification on selected properties of banana fiber paperbricks

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Abayomi A. Akinwande ◽  
Adeolu A. Adediran ◽  
Oluwatosin A. Balogun ◽  
Oluwaseyi S. Olusoju ◽  
Olanrewaju S. Adesina
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Moisture Absorption ◽  
Water Volume ◽  
Banana Fiber ◽  
Fiber Loading ◽  
Banana Fibers ◽  
Alkaline Modification

AbstractIn a bid to develop paper bricks as alternative masonry units, unmodified banana fibers (UMBF) and alkaline (1 Molar aqueous sodium hydroxide) modified banana fibers (AMBF), fine sand, and ordinary Portland cement were blended with waste paper pulp. The fibers were introduced in varying proportions of 0, 0.5, 1.0 1.5, 2.0, and 2.5 wt% (by weight of the pulp) and curing was done for 28 and 56 days. Properties such as water and moisture absorption, compressive, flexural, and splitting tensile strengths, thermal conductivity, and specific heat capacity were appraised. The outcome of the examinations carried out revealed that water absorption rose with fiber loading while AMBF reinforced samples absorbed lesser water volume than UMBF reinforced samples; a feat occasioned by alkaline treatment of banana fiber. Moisture absorption increased with paper bricks doped with UMBF, while in the case of AMBF-paper bricks, property value was noted to depreciate with increment in AMBF proportion. Fiber loading resulted in improvement of compressive, flexural, and splitting tensile strengths and it was noted that AMBF reinforced samples performed better. The result of the thermal test showed that incorporation of UMBF led to depreciation in thermal conductivity while AMBF infusion in the bricks initiated increment in value. Opposite behaviour was observed for specific heat capacity as UMBF enhanced heat capacity while AMBF led to depreciation. Experimental trend analysis carried out indicates that curing length and alkaline modification of fiber were effective in maximizing the properties of paperbricks for masonry construction.

scholarly journals Testing a Gypsum Composite Based on Raw Gypsum with a Direct Admixture of Paraffin and Polymer to Improve Thermal Properties

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3241
Author(s):  
Krzysztof Powała ◽  
Andrzej Obraniak ◽  
Dariusz Heim
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Phase Change ◽  
Large Scale ◽  
Building Materials ◽  
Residential Buildings ◽  
Energy Performance ◽  
Polymer Content ◽  
Volumetric Heat Capacity

The implemented new legal regulations regarding thermal comfort, the energy performance of residential buildings, and proecological requirements require the design of new building materials, the use of which will improve the thermal efficiency of newly built and renovated buildings. Therefore, many companies producing building materials strive to improve the properties of their products by reducing the weight of the materials, increasing their mechanical properties, and improving their insulating properties. Currently, there are solutions in phase-change materials (PCM) production technology, such as microencapsulation, but its application on a large scale is extremely costly. This paper presents a solution to the abovementioned problem through the creation and testing of a composite, i.e., a new mixture of gypsum, paraffin, and polymer, which can be used in the production of plasterboard. The presented solution uses a material (PCM) which improves the thermal properties of the composite by taking advantage of the phase-change phenomenon. The study analyzes the influence of polymer content in the total mass of a composite in relation to its thermal conductivity, volumetric heat capacity, and diffusivity. Based on the results contained in this article, the best solution appears to be a mixture with 0.1% polymer content. It is definitely visible in the tests which use drying, hardening time, and paraffin absorption. It differs slightly from the best result in the thermal conductivity test, while it is comparable in terms of volumetric heat capacity and differs slightly from the best result in the thermal diffusivity test.

scholarly journals Mechanical and Durability Properties of Portland Limestone Cement (PLC) Incorporated with Nano Calcium Carbonate (CaCO3)

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 905 ◽  
Author(s):  
Lochana Poudyal ◽  
Kushal Adhikari ◽  
Moon Won
Keyword(s):  
Calcium Carbonate ◽  
Environmental Sustainability ◽  
Green Infrastructure ◽  
Durability Properties ◽  
Portland Limestone Cement ◽  
Global Environmental ◽  
Depth Study ◽  
Series Of Experiments ◽  
Limestone Cement ◽  
New Generation

Despite lower environmental impacts, the use of Portland Limestone Cement (PLC) concrete has been limited due to its reduced later age strength and compromised durability properties. This research evaluates the effects of nano calcium carbonate (CaCO3) on the performance of PLC concrete. The study follows a series of experiments on the fresh, hardened, and durability properties of PLC concrete with different replacement rates of nano CaCO3. Incorporation of 1% nano CaCO3 into PLC concrete provided the optimal performance, where the 56 days compressive strength was increased by approximately 7%, and the permeability was reduced by approximately 13% as compared to Ordinary Portland Cement (OPC) concrete. Further, improvements were observed in other durability aspects such as Alkali-Silica Reaction (ASR) and scaling resistance. Additionally, nano CaCO3 has the potential to be produced within the cement plant while utilizing the CO2 emissions from the cement industries. The integration of nanotechnology in PLC concrete thus will help produce a more environment-friendly concrete with enhanced performance. More in-depth study on commercial production of nano CaCO3 thus has the potential to offer a new generation cement—sustainable, economical, and durable cement—leading towards green infrastructure and global environmental sustainability.

Heat capacity and thermal conductivity of LiCl.7H2O

1993 ◽  
Vol 5 (24) ◽  
pp. 4007-4012
Author(s):  
N Ahmad ◽  
C J Adkins ◽  
W A Phillips
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity

Onset of Natural Convection from a Suddenly Heated Horizontal Cylinder

1980 ◽  
Vol 102 (4) ◽  
pp. 636-639 ◽  
Author(s):  
J. R. Parsons ◽  
J. C. Mulligan
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Stability ◽  
Heat Capacity ◽  
Natural Convection ◽  
Stability Analysis ◽  
Horizontal Cylinder ◽  
Finite Cylinder ◽  
Global Motion ◽  
Experimental Apparatus

A study of the onset of transient natural convection from a suddenly heated, horizontal cylinder of finite diameter is presented. The termination of the initial conductive and “locally” conuectiue heat transfer regime which precedes the onset of global natural convection is treated as a thermal stability phenomenon. An analysis is presented wherein the effects of finite cylinder diameter, cylinder heat capacity, and cylinder thermal conductivity are included in calculations of the convective delay time. A simple experimental apparatus is described and data presented. The thermal stability analysis is confirmed experimentally and data is presented which indicates localized natural convection prior to global motion.

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