Construction Techniques Related to Clay Soils: A Case Study in Africa

Abstract

Clay, as one of the soils, must be assessed before being used for particular purposes such as cement production, and the assessment involves detailed site investigations conducted through laboratory or in situ equipment; thus, over the years, different systems or methods, such as stabilization, earth building, nanotechnology, and investigations methods, have been improved. However, although improvements have been made, there are still challenges and gaps within the systems and processes in terms of construction, consumption, usage, properties, etc.

1. Introduction

Clay, being the oldest material and most effective material on earth, has been used in various activities, and due to advancement (sixteenth century/1601 AD), humans have managed to use the soils in site investigation, foundation, walls, windows and doors, floor, ceiling, roof, cement production, paper making, landscape features, paver bases, house foundation, chemical filtering, brick manufacture, clinker adsorbent, architecture, construction engineering, clinker, and soil stabilization.

So, this is a deposit or fine material formed from weathering of sedimentary rocks described as having particle size of less than 0.002 mm by ASSHTO, USDA, and MIT, and according to UCS, it is classified as fines (silt and clay) less than 0.075 mm; however, it becomes hard when heated and soft when cooled, but according to [1] records, when soil was first used since the ancient past were not available. Technological advancement has resulted in new construction methods because the twenty-first century requires intelligent and sustainable construction techniques to reduce environmental impact and supplement efficiency. However, tracing the history of construction techniques within Africa was tricky since there were no clear boundaries on when each was first used.

1.1 Site investigation

Every infrastructure is supported by soil; hence, its stability and safety depend on the soil properties, which are supposed to be determined through, for example, desk study, site survey, topographic and hydrographic, geological and hazard mapping, subsurface investigation and dilapidation or precondition survey, etc., and it is the main stage in project designs, thus defined as an assessment and evaluation of soil or bedrock characterization.

Sampling, such as standard split spoon, thin-wall tube, and piston sampler, should be done to be able to obtain samples used for the routine; laboratory tests, such as moisture content, plasticity, shrinkage, particle size distribution, density, specific gravity, particle density, compaction, shear strength, permeability, pore water pressure, suction, compressibility, consolidation, standard penetration, cone penetration, pressure meter, flat dilatometer, vane shear, and plate loading, are the in situ tests conducted, but engineers in developing countries have resorted to adopting low-standard methods due to funds and technical knowledge. So for the case of laboratory tests, for example, to determine the moisture content, consecutive tests must be conducted by drying simultaneously to a particular weight, at a temperature ranging from 105 to 110ºC not exceeding 50ºC until there is no further mass loss, then the other laboratory tests such as liquid limit, shrinkage, particle size distribution, particle density, bulk density will be carried out according to the [2, 3] shear box and triaxial tests [4], and permeability tests [5]. Furthermore, in situ soil suction can be measured by tensiometers, pore water pressure by vacuum pressure gauge or pressure transducer, compressibility by an oedometer or triaxial, and consolidation by an oedometer.

FVT and CPT/CPTU are generally the most direct and reliable in soft soils, DMT applies to a wide range of soil, PMT is best suited from medium to very stiff clays, SBPMT is challenging to deploy, SPT is not suited to very soft clay, and PLT is mainly used at shallow depths or excavations [6]. In Uganda, the in situ method commonly used method is standard penetration (SPT), then shear box and triaxial tests for laboratory testing [7]; however, there is a delay in identifying appropriate methods appropriate for each country within Africa.

1.2 Building technology

This is a collection of methods and technical processes used in construction or architecture, and in Africa, cement has dominated the construction industry, but the earth is a commonly used material in masonry techniques, for example, sun-dried or kilns-fired Adobe, cob, compressed earth blocks, rammed earth construction, earth shielding, wattle, and daub products. Although these are cheap and easy to construct, they historically lead to weak houses, which are affected by floods and seismic events, so techniques, such as stabilization, were introduced in the second half of the last century to increase the strength and durability of the materials.

1.2.1 Earth building

This is a construction technique performed by mixing reasonably dry inorganic subsoil, non-expansive clay, sand, and aggregate, which requires dampening, mechanically pressing at high pressure, and drying the resulting material.

Cob construction is comprised of materials such as clay soil, coarse, straw, and water, after which the mix is used to create walls without formwork or mechanical ramming, but the mixture is applied so that when one course dries, the construction continues.

Adobe blocks are an unburned mud product, molded in pieces and sun-dried, and their manufacture is a straightforward process, and it was began to be used from 10,000 to 8000 BC [8]. A crater-like mound of earth is made on or near the site of the proposed structure, and after pouring water into it, then it is puddled to a plastic consistency by the workers, or adobero tramping barefooted throughout the mass or, better still, by hoeing to ensure a more thorough mixture. Then 1.5-inch or two-inch thick layers of straw or chopped hay, preferably of short lengths, are spread over the top, and the entire mass is again kneaded to distribute the binder uniformly. To prevent the straw from working to the bottom, it should not be added until the material has been well-puddled. The latter, along with the thoroughness with which the puddling is done, largely depends on the reduction of cracks that occur during sun drying and the material’s ultimate strength.

Rammed earth construction, initially in North Africa and the Middle East, was a technique used, and soils were compacted between formwork, then removed after the soil has dried, thus resulting in a structural component [9, 10], then wattle and daub is where a frame is created with secondary and primary timbers, and the main timbers support the secondary so that the mud produced is placed unto the frame made.

Traditionally, wooden molds were initially used to make blocks, but over the years, methods of machine technology to produce blocks have progressed, for example, the CINVA-RAM press machine in Bogota-Colombia (1950), machine in Uganda (1990), and a manual interlocking in Kenya, which produces curved, straight double interlocking, wide format interlocking blocks, after which these blocks are used for construction of water tanks, and wall creation, etc. (Figures 1–6) [11].

Figure 1.

Compressed earth blocks.

Figure 2.

Adobe blocks.

Figure 3.

Cob.

Figure 4.

Rammed earth.

Figure 5.

Earth sheltering.

Figure 6.

Wattle and daub.

1.2.2 Nanotechnology

This combines polymers (natural or synthetic), nano clay, and polymers are substances of larger molecules comprised of several chemical units named macromolecules. The nano clay differs by the different minerals, such as montmorillonite, bentonite, kaolinite, hectorite contained within, and there are three synthesis methods, for example, solution blending, melt blending, and in situ polymerization. Solution blending yields better results than melt blending due to the proper dispersion of the clay within the polymer matrix, and due to its low viscosity and high agitation power, but melt blending is considered industrially viable and eco-friendly, with high economic potential. Generally, in situ polymerization is widely used.

Solution blending is a combination of a polymer or prepolymer, clay in a solvent such as water, chloroform, or toluene, after which the polymer chains intercalate and displace the solvent within the interlayer of the clay, thus polymer/nano clay composites will be formed. The process is comprised of three stages, namely the dispersion of clay in a polymer solution, controlled removal of the solvent, and composite film casting.

Melt blending is where the required amount of intercalated nano clay particles are mixed with polymers at temperatures above the polymers’ softening point in the presence of the inert gas, then in situ polymerization is comprised of in situ monomer and nano clay interaction, and polymerization is comprised of initiation, propagation, and termination, then there are three methods namely: surface-initiated controlled/living radical polymerization (SI-CLRP), controlled radical-mediated photopolymerization (P-CRP), click coupling chemistry, and miniemulsion polymerization [12].

In Nigeria, the nano clays were mixed by hydration with various clay soils from Dogon-ruwa, functionalized, and characterized by the use of Raman spectroscopy, thermogravimetry, Brunauer Emmett Teller (BET), and particle sizer [13], then they were used as a partial replacement of cement in the road concrete pavement construction. Furthermore, the nano clay was dehydroxylated at 720°C, then characterized, and XRF equipment was used for the particle geometry; thus, it showed that the concrete formed was efficient under stormwater control and was recommended for low axle or low trafficked road design and construction, as well as aquifer recharge based on the flexural strength [14]. In Algeria, it was confirmed that when the clay soils were synthesized by ultrasonication with poly-glycidyl methacrylate (GMA) or nano clay composites, thermal stabilities were improved [15, 16].

1.2.3 Soil stabilization

This refers to making soil more robust and waterproof for a particular purpose, and there are two types of stabilization, namely surface (when the influence zone is less than 1 mm) and ground improvement (when the influence zone is more than 1 mm).

Surface stabilization consists of mechanical, physical, chemical, and physiochemical. Mechanical stabilization is where mechanical energy is used, for example, rollers, plate compactors, and tampers, and physical is done by cement, lime, bitumen, chemicals, and resin. Chemical stabilization is done by adding chemicals, for example, calcium chloride, sodium chloride, sodium silicate, polymers, and chrome lignin, and ground improvement consists of deep compaction, soil replacement, preloading, draining and GWT control, injection grouting, soil freezing, and use of geotextiles. Deep may be done by dynamic compaction or consolidation, vibro-compaction, or compaction piles, and soil replacement is when a weak/soft/organic soil is removed and replaced with compacted engineering soil. Preloading is done when 1.2–1.3 times the designed load is applied to allow desired settlement and accelerate consolidation. Drainage and GWT are where drains attain groundwater conditions, and lowering GWT or sometimes blanket drains and vertical sand drains are employed to accelerate the consolidation process. Injection grouting is where various fluid grouts are injected into the boreholes/weak soils and replaced by special pressure techniques, then soil freezing geotextile is correctly embedded in the soil and contributes to its stability.

In ancient times, lime was first used around 3000 B.C. for the Shensi Pyramids in China and 6500 B.C. in Syria [17, 18, 19], then in the seventh century B.C., the Chinese used lime in the construction of the Great Wall, bridges, underground chambers, and the clay or gravel soils were stabilized by the use of lime [5, 7, 20, 21]. In 1920, in the USA and Germany, it is where soil stabilization began in modern times, but the first tests on stabilization were done in the USA in 1904 [8, 17, 22, 23]. So, in order to demonstrate the solution in Africa, stabilization research has been done in the following countries.

1.2.3.1 Sandy soils

In the western provinces of Zambia (Mongu, Senanga, and Sesheke) in order to demonstrate the solution to the scarcity of road building materials, the sand samples were characterized, stabilized with cement and bitumen according to the design mixes selected, and California bearing ratio (CBR), unconfined compressive strength (UCS), indirect tensile strength (ITS), and Marshall stability tests were conducted, thus the sand properties were improved [24]. Additionally, in the Southern Sahara desert of Africa, during stabilization mixtures of high erodible soils, bentonite and, kaolinite were wetted with simulated rain, dried, and tested with wind tunnel with a brader at a free stream wind speed of 14 m/s or without abrader (wind only), and the results showed that the crushing resistance increased significantly with increasing clay content when a brader is available, then at the same time soil loss increased whenever the clay content increased, and furthermore, the loss ranged from 20 to 30 times more than the one from the trays treated with bentonite per kg of sand. Bentonite was more effective than kaolinite, and wind susceptibility was greatly reduced.

In Uganda, due to the sand abundance locally, clay samples were mixed with sand % proportions between 20 and 80%, and numerous laboratory experiments were conducted. The results confirmed that sand blending diminishes the shrinkage behavior of clayey soils. The properties of the clayey soils such as shrinkage behavior diminished, plasticity index and shrinking potential decreased, MDD increased, OMC decreased, unconfined compressive strength decreased, internal friction angle concerning shear strength parameters was enhanced, soil cohesion decreased, and consolidation settlement was lowered [25].

1.2.3.2 Restoration

In Ksar of Ait Benhadou, Morocco, the samples from the structure, were collected and analyzed by X-diffraction and X-ray fluorescence, then a representative sample was stabilized with three aggregates (lime, cement, and straw), and minerals, such as calcite and quartz, were encountered. They were rich in iron and potassium content and had a low plasticity (P.I. = 7%), which is slightly lower than the plasticity value required by the Moroccan standard for earth constructions. Generally, the results showed that the stabilized clayey soil properties were improved such as density, porosity, water absorption, and high thermal insulation [26].

In Namibia, the study of tailings left un-rehabilitated after 200 mines were exploited, considered the successful stories and lessons from other phytoremediation work, specifically phyto stabilization projects, which dealt with restoring, contaminated mine tailings. The study analyzed the OMT results using X-ray fluorescence geochemical data to understand the heavy metals in the tailings, and it further used GIS to assess the distribution of heavy metals on OMT, specifically those with high phytotoxic levels. Finally, the study addressed its primary objective, which was to provide the Namibian government with suggestions and recommendations on the best remedial measures for the remediation of heavy metal-contaminated mine tailings [19].

1.2.3.3 Heaving expansive clays

In Egypt, representative samples of 10% of GGBS and the replacement of 30% of hydrated lime were mixed with clay content and then cured within representative conditions: 20°C with 90–100% relative humidity, 350°C with 50–60% relative humidity for 12 months, after which compaction, swelling, plasticity, and UCS tested were conducted. X-ray diffraction, scanning electron microscopy, differential thermal analysis, and nuclear magnetic resonance (NMRC) were used to determine the reaction products. Results showed that engineering properties improved; the addition of lime showed a more significant improvement, maximum dry density (MDD) decreased, and optimum moisture content (OMC) increased with increasing GGBS [27]. Then in Morocco (Kenitra, Sidi Kacem, Tangier, and Tetouan) clay samples containing various minerals, such as hydrated Lime, montmorillonite, illite, and kaolinite, were mixed with pure standard clays, and a series of laboratory tests were conducted such as Atterberg limits, X-ray diffraction, hydration heats, and cementing; hence, there was a reduction in plasticity and an improvement in compaction properties, and the amount of lime needed to modify clay soil varied from 3 to 6% [28].

In Nakapiripirit district, (Northern Uganda), expansive soil samples were mixed with EAF slag dosages of 0, 5, 10, 15, 20, and 30%, after which laboratory tests were conducted on each mixture, and the expansive clay properties were improved (Table 1) [48].

No	Country	Problem	Materials, procedure, results, and conclusions
1.0	Ghana	Weak sub-base soils	Materials; Laterite Lime Cement Procedure; A refilling box was used to divide the sample into two equal parts, whereby one part was again divided into two equal parts, and this was done continuously until a proper level of mixing had been attained. Results; A total of 6% addition of lime to the sample resulted in P.I., L.L., and CBR values that passed GHA specifications for both base and sub-base courses [29].
2.0	Kwali Area Council in Abuja, Nigeria	Effect of stabilizing lateritic soil with a combination of bitumen emulsion and cement.	Materials; Lateritic soils Bitumen emulsion Cement Procedure; The additives (4, 6, and 8%), bitumen emulsion, and cement (100:0, 75:25, 50:50, 25:75, and 0:100) were considered, and UCS and CBR tests were determined. Results; Both values increased as the cement component increased for both soil samples, and so the strength of the soil improved [30].
3.0	Nigeria	Geotechnical properties	Materials; Periwinkle shell powder (PSP) Lateritic soil. Procedure; 2, 4, 6, 8, and 10% of PSP and OPC were added to the un-stabilized lateritic soils, and NMC, P.L., and P.I. tests were conducted, respectively. Results; An increase in maximum dry density (MDD) and OMC was observed whenever cement and periwinkle shell powder (PSP) were added, and PSP recorded an increase of 5.6% in CBR value compared with OPC, which recorded a rise of 34% in CBR value, so periwinkle shell powder (PSP) can be used as a good stabilizer for clayey or lateritic [31].
4.0	Kumasi Ghana	Heavy metal pollution	Materials; Low-grade CaO Heavy metals Leachate Procedure; Five mixtures of leachate (each 100 ml) and LG-CaO (10, 15, 20, 25, and 30 g) were prepared, and weighed and mixing was carried out with magnetic stirrers at 110 rpm for 8 hours, then the samples were kept at 21o°C for 21 days [20, 32, 33]. Soil samples each weighing 100 gl were mixed with a % LG-CaO such as 10, 15, 20, 25, and 30%, and each mixture was stirred by use of magnetic stirrers at 110 rpm for eight hours, then the mixtures were kept at 2100°C for 21 days [22, 34]. Then 10 ml and 100 g of distilled water were used to mix each mixture to remove minerals that may have been caused by the tap water [35]. In the second part, 100 g and 10 g of sand, LG-CaO contents were kept constant by weight while the water proportions [2, 27, 30, 36, 37] varied. So, after blending, compaction was done, and samples were kept at 250°C for 21 days [20, 32, 33]. After the heavy metal stabilization, the mixtures were again digested by use of triacid mixture. The concentrations of metals (Cd, Fe, Zn, and Cu) were analyzed by using an atomic absorption spectrometer (SPECTRA AA 220 Air-acetylene Flame) [38, 39]. After 1, 5, 10, 17, and 21 days, the electrical conductivity, pH, and temperature of the mixtures were always measured before and after the stabilization treatment with a palintest multipurpose pH meter [11, 40, 41]. Results; Concentrations of heavy metals (Cd, Cu, Fe and Zn) in the soil investigated were found to be above the environmental protection agency (EPA) and World Health Organization (WHO) guidelines, which can be a potential source for some heavy metals in the environment. In contrast, the physicochemical properties (temperature, clay content, moisture content, electrical conductivity, and pH) of soil samples and the leachate sampled were below the EPA threshold values. An increase in LG-CaO to the sample while maintaining the sand and water proportions constant to increase the P.H. or varying water proportion keeping sand and CaO constant led to a reduction of the heavy metal concentration within the soils after stabilization treatment [42].
5.0	Africa	Cost-effective stabilization	Materials; Soil Kilned Powdered Glass Wastes Procedure; The soil samples were exposed to an air room at room temperature and dried thoroughly, then they were disintegrated, and representative samples were selected to be used for the required tests. After this, the samples were kilned at a temperature of 700°C for 2 hours then cooled for 24 hours for further tests. A #200-micron sieve was used for sieving after having crushed the soil. The % proportions of the mixture were 75% soil kilned and 25% powdered glass waste (3:1). Then % of the stabilizers varied, for example, 5, 15, and 25% of the total weight of the sample. Results; MDD, CBR, and UCS values were increased, while the OMC decreased after the 14 days of curing. Additionally, a free swell of expansive soil and CBR swell values were improved, and montmorillonite illite minerals were used for the X-ray di¢raction (XRD) test to have disappeared. Montmorillonite and illite minerals disappeared [43].
6.0	North of Morocco	Sliding phenomena	Materials; Reinforced concrete piles Finite element modeling Procedure; Finite element modeling was used to check reinforced concrete piles, and the elastoplastic Mohr-Columb model was used for soil modeling. Inclinometers were installed on the site to measure soil deformation over time. Results; The horizontal displacement of the soil was close to the measured in situ. Also, the measured displacements revealed that the method of reinforcement by piles used in some areas of the study effectively stabilizes landslides, and not others [44].
8.0	All countries	Environmentally friendly and sustainable stabilizers.	Materials; Waste tires Procedure; Clays mixed with an optimum of the waste tire 20% by weight gave better performance results than those from Geogrid. Additionally, engineering properties were improved after adding 2% waste tire rubber fibers to cement-stabilized bentonite clays. Then, UCS ductility behavior was also achieved. (30–50%) content coarse (4.75–2.00 mm) shredded tire waste improved the expansive black cotton soil geotechnical properties than the fine shredded tire, and it was observed that soil reinforced with a shredded tire tested by use of a square model footing showed that the bearing capacity of shredded tire reinforced soil increased by 2.68 times when 5% of soil-shredded tire mixture was used but when 5% of the soil-shredded tire mixture is added, there was a reduction in the bearing capacity caused due to excess shredded tire creating voids leading to the settlement of the foundations. During stabilization mix ratios of clay soils named kaoline with tire crumbles, fly ash tire was mixed, and after mixing, the MDD decreased and OMC increased leading to a maximum bearing capacity which ranged from 5 to 20%. Furthermore, clay was mixed with sand soils and then stabilized by use of waste tire textile of % ranging from 0.5 to 4% thus leading to an increased bearing capacity [45].
9.0	Keruing sawdust	Environmentally friendly and sustainable stabilizers.	Materials; Saw dust Procedure; A total of 3% of Keruing sawdust mixed with expansive soils improved the expansive soil’s properties, but durability tests were recommended. A total of 0, 2.5, 5, 7.5, 10% of sawdust and 12.5% of the dry unit weight soil were used to stabilize the expansive soil, and the swelling potential and swelling pressure decreased with the increased percentages of sawdust addition. UCS increased sawdust addition by 7.5%, and beyond that, they started reducing. Furthermore, different quantities of sawdust (1, 2, 3, and 5%) were also used to stabilize the expansive soils, and it was found that smaller percentages of sawdust brought a tremendous increase in the strength of the stabilized soils and 3% of optimum portion of sawdust was influential in the stabilization of the expansive soil, then beyond that there was a decline in strength observed, so it was concluded that sawdust could be used to fill the voids in soils. In Southwestern Nigeria, various saw dust ash %, such as 0, 2, 4, 6, and 8%, were used to stabilize the soils, and optimal results were obtained when 6% of SDA was used. Additionally, 4% of the dry weight of the soil was used to stabilize the soil, which improved the properties. So, the CBR in both soaked and unsoaked conditions improved when 70% lateritic soil and 30% saw mixture were formed, and when percentages from 0, 2, 4, 6, and 8% by the dry unit weight of soil were used, the standard hydraulic conductivity requirement was improved, but 8% was the optimum content [45].
10.0		Environmentally friendly and sustainable stabilizers	Materials; Fly ash Procedure; The collapsibility potential of gypseous soil decreased when stabilized by the fly ash class F activated with KOH and NaOH, and it was identified that geopolymer fly ash had higher sulfate resistance than Portland cement. 0, 5, 10, 15, 20, and 30% fly ash were incorporated, and there was an increase in the maximum dry unit but a reduction in the optimum moisture content. Results; Whenever fly ash was increased and the curing period lengthened, the UCS increased, thus the highest UCS was obtained when 30% of flash was used after 90 curing days, then the strength properties of marine soils stabilized with cement were improved than those stabilized by fly ash in the short run (7–28 days). The soil Atterberg test results improved by reducing the plasticity index from 20.2% (non-stabilized) to 13.1% when the soils were stabilized with 15% fly ash calcium fly ash (0, 3, 6, 9, 12, and 15% of the dry unit weight), which was class C fly ash because the sum of SiO2, Al2O3, and Fe2O3 is 27.53, which is below 70% and palm oil fuel ash [45].
11.0	Lake Chad basin, Central Africa	Ceramics applications	Materials; Clays samples Procedure; Particle size distribution, specific surface area, Atterberg limits, swelling rate, and clay activities were conducted then also XRF and XRD techniques were also conducted. Samples were fired in the range from 750 to 1250°C. Color, sound test, weight loss, bulk density, firing shrinkage, and compression strength measured the firing characteristics. Water absorption was determined during 3 months in water immersion. Results; Plasticity was high and made up of smectites associated with kaolinite, illites, quartz and feldspar, and a high proportion of silica and iron, but less alumina, high iron content responsible for the reddish color in firing. So, from the results, bulk density, linear firing shrinkage and compressive strength, and water absorption were < 20% obtained, which showed that the clays were suitable for producing ceramics and tiles [46].
12.0	Algeria, Morocco and Tunisia	potential use for ceramic	Materials; Clays soils Results; Illite ranged from 12 to 38%, and kaolinite was 12–17%, as seen from the three countries. Tunisia was comprised of 15% smectite, 4% palygorskite, 30% quartz, and 15% calcite, but the other countries were not mentioned, so it means they had very little maybe. Large amounts of iron (>5.6%), earth-alkaline oxides (>6.9%), and high values of LOI (>12%). The plasticity (P.I.) ranged from 16 to 40%, and Algeria had the highest requiring particular attention and careful temperature control during drying to avoid the deformation and the formation of cracks in the ceramic bodies. In contrast, the Tunisian and Moroccan clays (P.I. = 18 and 16%, respectively) show acceptable behavior in shaping and drying. Indeed, the amount of fraction upper 63 μm was less than 2%. The abundance of components, such as Fe2O3, CaO, MgO, K2O and Na2O, influences the main transformations during firing. Conclusion; The firing shrinkage, water absorption, and flexural strength were within the ceramic international standards (ISO) [47].

Table 1.

Other construction techniques related to clay soils in Africa.

1.3 Clinker

These are solids which appear as nodules or lumps measuring between 3 mm and 25 mm or 0.12–0.98 inches in diameter produced during the kilning stages when limestone is heated with clay within a temperature from 1400 to 1500°C, after which gypsum will be added and then grounded to obtain cement. This is also a binder in various cement products, namely ground granulated blast furnace slag, Pozzolana, silica fume, and composite, and the clinker components are an alite, belite, aluminate, then the types are sulfate resistant, low heat, white, low alkali, belite calcium-sulfo aluminate ternesite, etc.

In Malawi, Cote d’Ivoire, Cameroon, Algeria and Ghana, gas suspension systems were created. The clay calciner system was expected to substitute between 30 and 40% of the clinker in the final product and these products improved the cement quality and controlled carbon dioxide emissions by up to 40% tone. In Nigeria, Level 1 reduction in greenhouse gas emissions was achieved when the calcined clays, limestone powder and ordinary Portland cement were used, and additionally, and this solved the housing deficit around Africa [49].

1.4 Adsorbent

This is the accumulation of large molecular species at the surface of liquid or solid phase compared to the bulk, and it arises due to unbalanced or residual forces at the surface of the liquid or solid phase. Adsorption happens at the surface of a substance, and absorption means uniform distribution of the substance throughout the bulk, for example, low energy electron diffraction (LEED), photoelectron spectroscopy (PES), and scanning tunneling microscopy (STM). Adsorption can occur in liquids or solids, and there are two types of adsorptions, namely physical or physisorption and chemical or chemisorption, then adsorption processes are studied through isotherm, GIBBs, Freundlich isotherm, Langmuir isotherm, multilayer, and BET. The method of adsorption is useful both in industrial and domestic, for example, heterogeneous catalysis, removal of coloring material, ion exchange resins, adsorption indicators, gas masks, dyeing of cloth and de humidizers, etc.

In Algeria, activated clay was used as an adsorbent to remove methyl orange (MO) from an aqueous solution, and pseudo-second order and second order were used, but the kinetic process followed the pseudo-second-order model. Additionally, the Langmuir and Freundlich isotherms models were used in the data description, and the results showed that all models obtained a good correlation. So, with nearly 30 minutes of contact time, the adsorption reached equilibrium and then became favorable at a lower pH [50].

2. Conclusion

The most significant findings are improvements in machine systems, procedures, and clay soil properties, and these will help to mitigate climate change during the manufacture of the products and execution of structures leading to saving of trees. However, although improvements were made to construction techniques related to clay soils, there is a need to implement them within the daily construction rather than only demonstrating most of them in the laboratory.