12 research outputs found
Application of Gene Expression Programming to Evaluate Strength Characteristics of Hydrated-Lime-Activated Rice Husk Ash-Treated Expansive Soil
Gene expression programming has been applied in this work to predict the California bearing ratio (CBR), unconfined compressive strength (UCS), and resistance value (R value or Rvalue) of expansive soil treated with an improved composites of rice husk ash. Pavement foundations suffer failures due to poor design and construction, poor materials handling and utilization, and management lapses. The evolution of sustainable green materials and optimization and soft computing techniques have been deployed to improve on the deficiencies being suffered in the abovementioned areas of design and construction engineering. In this work, expansive soil classified as A-7-6 group soil was treated with hydrated-lime activated rice husk ash (HARHA) in an incremental proportion to produce 121 datasets, which were used to predict the behavior of the soil’s strength parameters utilizing the mutative and evolutionary algorithms of GEP. The input parameters were HARHA, liquid limit (wL), (plastic limit wP, plasticity index IP, optimum moisture content (wOMC), clay activity (AC), and (maximum dry density (δmax) while CBR, UCS, and R value were the output parameters. A multiple linear regression (MLR) was also conducted on the datasets in addition to GEP to serve as a check mechanism. At the end of the computing and iterations, MLR and GEP optimization methods proposed three equations corresponding to the output parameters of the work. The responses validation on the predicted models shows a good correlation above 0.9 and a great performance index. The predicted models’ performance has shown that GEP soft computing has predicted models that can be used in the design of CBR, UCS, and R value for soils being used as foundation materials and being treated with admixtures as a binding component
Predicting the rheological flow of fresh self-consolidating concrete mixed with limestone powder for slump, V-funnel, L-box and Orimet models using artificial intelligence techniques
In this paper, selected materials that influence the viscosity of the self-consolidating concrete (SCC) are introduced like the Limestone Powder (LSP), the High Range Water Reducing Admixture (HRWRA), which reduce the interparticle force between concrete constituents like the aggregates, and other superplasticizers. Moreover, in serious attempts to design the SCC for different infrastructure requirements, there have been repeated laboratory visits, which need to be reduced. In this research paper, the artificial intelligence (AI) methods: Artificial Neural Network (ANN), Evolutionary Polynomial Regression (EPR), and Genetic programming (GP) have been deployed to predict the slump flow (SF), V-funnel flow time (VFFT), L-box ratio (LBR) or passing ratio, and Orimet flow time (OFT) of LSP-admixed SCC. The independent variables of the predictive model were cement, LSP, water, water-binder ratio, HRWRA, sand, and coarse aggregates of 4/8 mm and 8/16 mm sizes. The flow tests were conducted after 5 minutes of waiting time after mixing. The model results showed ANN with superior intelligent learning ability over previous models in terms of overall performance
Pozzolanic Reaction in Clayey Soils for Stabilization Purposes: A Classical Overview of Sustainable Transport Geotechnics
Problematic soil stabilization processes involve the application of binders to improve the engineering properties of the soil. This is done to change the undesirable properties of these soils to meet basic design standards. However, very little attention has been given to the reactive phase of soil stabilization. This phase is the most important in every stabilization protocol because it embodies the reactions that lead to the bonding of the dispersed particles of clayey soil. Hence, this reactive phase is reviewed. When clayey soils which make up the greatest fraction of expansive soil come in contact with moisture, they experience volume changes due to adsorbed moisture that forms films of double diffused layer on the particles. When this happens, the clayey particles disperse and float, increasing the pore spaces or voids that exist in the soil mass. Stabilizations of these soils are conducted to close the gaps between the dispersed clayey soil particles. This is achieved by mixing additives that will release calcium, aluminum, silicon, etc., in the presence of adsorbed moisture, and a hydration reaction occurs. This is followed by the displacement reaction based on the metallic order in the electrochemical series. This causes a calcination reaction, a process whereby calcium displaces the hydrogen ions of the dipole adsorbed moisture and displaces the sodium ion responsible for the swelling potential of clayey soils. These whole processes lead to a pozzolanic reaction, which finally forms calcium alumina-silica hydrate. This formation is responsible for soil stabilization
Effect of exploration depth on microstructural behavior of subsurface soft clayey soil for foundation construction purposes
The geomorphological, microstructural pattern and mineralogical configuration of subsurface soils explored from 1-meter,
3-meter and 7-meter depths have been studied for the purpose of foundation materials suitability. Soils samples are
hauled from borrow sites to where they are utilized as foundation materials. In very most cases, this exploration is done
at varying depths and soil being an erratic geomaterial change in its important engineering characteristics with depth.
This laboratory examination was necessary to establish the microstructural behaviour and pattern of soils when they are
explored from different depths. The samples collected from different depths showed to be A-3 soils according to AASHTO
classification method and poorly graded according to the USCS. Also varying depth of the soil sample was characterized
by a proportional increase in moisture content; this as well applies to the `liquid limit, plastic limit and plasticity index
values respectively with an exception in the shrinkage limit, which reduces with increase in depth of soil sample. This can be
attributed to the erratic behavior of soil, which makes it change behavior from location to location and from depth to depth,
clayey contents changes with depth likewise its desiccation properties. The geomorphology and microstructure of the soils
show weaker configuration with increased depth of exploration to 7 meters. This shows that for any foundation purposes,
soils at both 3 meter and 7-meter depths require treatment to be suitable for construction purposes. Geo-constructions like
compacted earth liner systems, mechanically stabilized earths or backfills, pavement subgrade systems can be constructed
with the studied soils but care must be taken to modify the soils to meet the basic design considerations
Artificial intelligence prediction model for swelling potential of soil and quicklime activated rice husk ash blend for sustainable construction
Artificial intelligence (AI) algorithms of adaptive neuro-fuzzy inference system or the adaptive network-based fuzzy inference system (ANFIS) has been deployed to predict the swelling potential (SP) of treated weak soil. The soil was treated with quicklime activated rice husk ash (QARHA) and the prediction efficiency was compared with the previous outcomes of this operation from literature. The need for effective utilization of construction materials to achieve sustainable designs and monitoring of the behavior of built environment is the motivation behind the deployment of artificial intelligence in geo-environmental research and field operations. The use of ANFIS is common in different fields of science and business to predict the best fits from several data points. The results of this modeling exercise conducted with 25 datasets from mixture experimental treatment of soft soil with QARHA has shown that ANFIS is a better tool compared to the individual algorithms of ANN and FL and even the other artificial intelligence tools like scheffe, ANOVA, regression and extreme vertices methods. With performance index of 88% and correlation of about 71% in the ANFIS testing and 17% and 99% respectively in the ANFIS training, ANFIS proved to be a more powerful tool in achieving a more sustainable material utilization in earthwork constructions, design and monitoring of geotechnical systems performance
Overview of meshfree modeling of the flowability of fresh self-compacting concrete for sustainable structures
The flow of Bingham non-Newtonian incompressible fluids like concrete is associated with the large deformation of materials. The modeling and simulation of these fluids’ flow behavior by using conventional numerical methods. suffer problem-formulation setbacks due to mesh distortion. In order to compensate for the mathematical inefficiencies encountered in the process, particle-based methods have evolved and been applied. Also, the use of some particle-based methods produces a stretch of unreliability due to the Eulerian algorithmic trail, which visits every particle edge allowing for revisiting vertices during its operation. This makes the model path cumbersome and time-consuming. Concrete flow is an important element of sustainable infrastructural development, and its understanding strengthens the efficiency of concrete handling and placement during construction activities. In this paper, a mesh-free method of modeling the flowability of self-compacting concrete (SCC) known as the smoothed particle hydrodynamics (SPH) has been reviewed. It derives its advantage from the Lagrangian algorithmic trail. This explores its merits and demerits in the concrete construction industry to propose the best practices for the passing ability, filling ability, and dynamic stability of the flowing fresh concrete (FFC
Atterberg limits of modified compacted clayey soil for sustainable green subgrade structure
Atterberg limits are one of the fundamental geotechnical parameters used to assess the settlement and other volume change parameters of engineering soils containing clays. This paper describes index test results on expansive soil treated with rice husk ash (RHA) and 5%, 10%, and 15% quicklime activated rice husk ash (QARHA) obtained using laboratory testing procedure. The cost of conventional binders used in earthwork has necessitated the need to look for cheaper materials that serve the same purpose. Also, the extent of environmental poisoning due to the use of cement is worrisome and has motivated the use of alternative and green supplementary cements in soils stabilization. However, previous research works have dwelt on the use of ash derived from the combustion of solid waste materials like rice husk ash. But the present work has gone a step further to activate the properties of rice husk ash with three proportions of quicklime and this novel procedure has not been reported by any work in recent times. After preliminary tests, the test soil was classified as highly plastic soil. The soil was further subjected to treatment exercise at the rate of 0% (control), 2%, 4%, 6%, 8%, and 10% addition of RHA, 5%-QARHA, 10%-QARHA, and 15%-QARHA by weight of test soil. The RHA addition improved the index properties; liquid and plastic limits and plasticity index at varying rates. The rates of improvement show that the higher the rate of activation of rice husk ash with quicklime, the higher the pozzolanic performance, which tends to cement the soil particles together and improve the consistency through flocculation. Finally, rice husk ash and its composites achieved by quicklime activation process have shown to be alternative cementing construction materials for use as binders in the modification of expansive soils utilized as subgrade materials
Erodibility of Nanocomposite-Improved Unsaturated Soil Using Genetic Programming, Artificial Neural Networks, and Evolutionary Polynomial Regression Techniques
Genetic programming (GP) of four levels of complexity, including artificial neural networks of the hyper-tanh activation function (ANN-Hyper-Tanh), artificial neural networks of the sigmoid activation function (ANN-Sigmoid), evolutionary polynomial regression (optimized with genetic algorithm) (EPR), and intelligent techniques have been used to predict the erodibility of lateritic soil collected from an erosion site and treated with hybrid cement. Southeastern Nigeria and specifically Abia State is being destroyed by gully erosion, the solution of which demands continuous laboratory examinations to determine the parameters needed to design sustainable solutions. Furthermore, complicated equipment setups are required to achieve reliable results. To overcome constant laboratory works and equipment needs, intelligent prediction becomes necessary. This present research work adopted four different metaheuristic techniques to predict the erodibility of the soil; classified as A-7-6, weak, unsaturated, highly plastic, high swelling and high clay content treated with HC utilized in the proportions of 0.1–12% at the rate of 0.1%. The results of the geotechnics aspect of the work shows that the HC, which is a cementitious composite formulated from blending nanotextured quarry fines (NQF) and hydrated lime activated nanotextured rice husk ash (HANRHA), improves the erodibility of the treated soil substantially and consistently. The outcome of the prediction models shows that EPR with SSE of 1.6% and R2 of 0.996 outclassed the other techniques, though all four techniques showed their robustness and ability to predict the target (Er) with high performance accuracy
Shrinkage parameters of modified compacted clayey soil for sustainable earthworks
The shrinkage limit is one of the Atterberg limits and is a fundamental geotechnical parameter used to assess the settlement
and other volume change parameters of engineering soils containing clays. This paper describes shrinkage limits and
index tests results on expansive soil treated with rice husk ash (RHA) and 5%, 10% and 15% quicklime activated rice
husk ash (QARHA) obtained using laboratory testing procedure. The representative soil was subjected to classification
tests and it was found to be high expansive soil, an A-7-6 soil according to American Association of States Highway and
Transportation Officials (AASHTO) and poorly graded according to Universal Soil Classification System (USCS). It was
classified as highly plastic soil. The soil was subjected to treatment exercise at the rate of 0% (reference), 2%, 4%, 6%,
8% and 10% addition of RHA, 5%-QARHA, 10%-QARHA and 15%-QARHA by weight of dry soil. The RHA addition
improved the shrinkage properties; shrinkage limit at varying rates ranging from 5.7%, to 27.9% for 2%, and 10% RHA
addition respectively with reference to the control experiment. And for the shrinkage index, the improvement rate was also
substantial i.e. 7.8% to 55.7% at 2% and 10% RHA addition respectively with reference to the control experiment. The
effect of rice husk ash activated with 5% quicklime lime (5%-QARHA) showed improvement rate of 6.6% and 34.4% at
2% and 10% 5%-QARHA addition respectively with reference to the control experiment. Also, the effect of rice husk ash
activated by 10% and 15% quicklime (10%-QARHA and 15%-QARHA) on the shrinkage properties was presented with
the rates of improvement which shows that the higher the rate of activation of rice husk ash with quicklime, the higher the
pozzolanic performance Finally, rice husk ash and its composites achieved by quicklime activation process have shown to
be alternative cementing materials for use as binders in the modification of expansive soils utilized as subgrade materials