scholarly journals Prediction of four-days Soaked California Bearing Ratio (CBR) Values from Soil Index Properties

2021 ◽  
Vol 40 (1) ◽  
pp. 28-38
Author(s):  
Pascal Ambrose ◽  
Siya Rimoy

California Bearing Ratio (CBR) laboratory testing is the conventional method for determining soaked strengths of pavement subgrades. The test requires careful preparation of soil samples followed by four days of water soaking before penetrating the samples using a standard plunger at prescribed rates to set depths. When the number of samples becomes large the determination of soaked CBR values becomes cumbersome as the test is laborious and time consuming. This study aimed at establishing an alternative way of determining soaked CBR by developing a model that would be used for estimating soaked CBR of fine- and coarse- grained soils without performing the CBR test. This has been achieved by correlating CBR values compacted at 95% Maximum Dry Density (MDD) with the soil index properties. The results show that soaked CBR values of fine-grained soils significantly correlate with specific gravity of soil (GS), Plasticity index (PI) and the grading modulus (GM) of the soil that yields a degree of determination of R2 = 0.91 and for coarse grained (A-2 type) soil, the soaked CBR values significantly correlate with specific gravity of soil and percentage of fines passing 0.075mm sieve size that yields a degree of determination of R2= 0.94.

2019 ◽  
Vol 9 (2) ◽  
pp. 93-99
Author(s):  
Hunar F. Hama Ali ◽  
Ahmed J. Hama Rash ◽  
Madeh I. Hama kareem ◽  
Daban A. Muhedin

This paper addresses the correlation between the liquid and/or plastic limits with the compaction characteristics, maximum dry density, and optimum moisture content (OMC), for fine-grained soils. In the previous studies, several attempts have been made to identify these two important parameters from other simple soil properties such as index soil properties. Some concluded that liquid limit shows a good correlation with compaction characteristics, while others observed that plastic limit does. In this work, many soil samples have been taken from various locations around Koya city and the required tests have been carried out. The results have been illustrated to identify whether soil index properties can correlate with the compaction characteristics. It is concluded that neither plastic limit nor liquid limit can provide an adequate correlation with maximum dry density and OMC. Contrary to the literature, liquid limit provides better correlations.


2021 ◽  
Author(s):  
Attah Fakeye ◽  
Olusegun Ige ◽  
Olufemi Ogunsanwo

California Bearing Ratio (CBR) is an important parameter used in designing pavement layers in road construction but testing this parameter requires time, labor, and huge cost. The study therefore applies multivariate approach to evaluate CBR based on contrasted geotechnical parameters along Ilorin-Lokoja highway. The results obtained showed that the migmatite-gneiss-derived soils are slightly more fines (< 0.075 mm; 7.4–59.6%), more plastic (PI; 1.6–39%), and have low strength (MDD = 1.8 mg/m3; CBR = 29.0%) than the metasediments (11–57.7%, 2.0–30%, 1.6 mg/m3, 23.6%) and older granite soils (8.2–32.7%, 2.6–13.4%, 1.7 mg/m3, 27.8%), respectively. The principal component analysis (PCA) revealed three major components (eigenvalues >1) which accounted for 83.8% of the total variance at the rate of 33.4, 14.7, and 11.4%. Major contributing variables for the components were fines (R = 0.87), plasticity index (R = 0.7), and coarse sand (R = 0.67%). Spatial distribution of these groups established interplay of sediment-gradation and moisture-connection evident in hierarchical cluster analysis that revealed patterns of homogeneity and soil relationships. Regression analysis established five models from predictor variables such as fines, activity, free swell, liquid and plastic limits, weighted plasticity index, optimum moisture content, and maximum dry density with the coefficient of determination (R2 = 0.33) and root mean square error (RMSE) of 7.80.


Author(s):  
Bhalchandra S. Pujari ◽  
Snehal Shekatkar

The ongoing pandemic of 2019-nCov (COVID-19) coronavirus has made reliable epidemiological modeling an urgent necessity. Unfortunately, most of the existing models are either too fine-grained to be efficient or too coarse-grained to be reliable. Here we propose a computationally efficient hybrid approach that uses SIR model for individual cities which are in turn coupled via empirical transportation networks that facilitate migration among them. The treatment presented here differs from existing models in two crucial ways: first, self-consistent determination of coupling parameters so as to maintain the populations of individual cities, and second, the incorporation of distance dependent temporal delays in migration. We apply our model to Indian aviation as well as railway networks taking into account populations of more than 300 cities. Our results project that through the domestic transportation, the significant population is poised to be exposed within 90 days of the onset of epidemic. Thus, serious supervision of domestic transport networks is warranted even after restricting international migration.


2020 ◽  
Vol 857 ◽  
pp. 259-265
Author(s):  
Jasim M. Abbas ◽  
Amer M Ibrahim ◽  
Abdalla M. Shihab

The civil engineering projects that includes soft clay within its activities has a serious concern of hazards, such hazards can be overcame by treating the existing soils by certain materials which are named as "stabilizers". The common materials that are highly used in this field are ordinary Portland cement, fly ash, lime and rice husk ash, etc. Each one of these stabilizers has its known shortcomings. The alkali activation of any alumina silicate source produces some kind of cost effective primary binding gel which is known as "Geopolymers". This study is devoted to investigate the role of liquid over fly ash ratio to some soil – FA based Geopolymers geotechnical properties. Such ratio is taken as 2.71, 3.167, 3.8 and 4.75 respectively within the experimental program and the investigated geotechnical properties are the specific gravity, liquid and plastic limit, compaction characteristics and California bearing ratio. The tests results showed that the maximum dry density decreased about 42 % at 2.71 liq/FA whereas this the specific gravity decreased 27 % at the same this ratio. In addition, the 3.8 and 4.75 of such limits revealed no plastic behavior due to the high presence of liquid.


2017 ◽  
Vol 6 (1) ◽  
pp. 30-42
Author(s):  
Elvira Kalaitzaki ◽  
George Kollaros ◽  
Antonia Athanasopoulou

Abstract According to their size, aggregates are classified in coarse grained, fine grained, and fines. The determination of fines content in aggregate materials is very simple and is performed through the aggregate washing during the sieving procedure to define the gradation curve. The very fine material consists of grains having a size lower than 63 μm. The presence of fines directly influences the composition and performance of concrete and asphalt mixtures (e.g. asphalt content, elasticity, fracture). The strength and load carrying capacity of hot mix asphalt (HMA) results from the aggregate framework created through particle-particle contact and interlock. Fines or mineral filler have a role in HMA. The coarse aggregate framework is filled by the sand-sized material and finally by the mineral filler. At some point, the smallest particles lose contact becoming suspended in the binder not having the particle-particle contact that is created by the larger particles. The overall effect of mineral filler in hot mix asphalt specimens has been investigated through a series of laboratory tests. It is clear that a behaviour influenced by the adherence of fines to asphalt film has been developed. The optimum bitumen content requirement in case of stone filler is almost the same as that for fly ash. It has been found that the percentage of fly ash filler is crucial if it exceeds approximately a value of 4%.


2019 ◽  
Vol 13 (2) ◽  
pp. 160-179
Author(s):  
Andrias Suhendra Nugraha ◽  
Jordan D. Fahlevi ◽  
William H. Soentpiet

Suatu konstruksi jalan terdiri dari beberapa lapisan yaitu subgrade (tanah dasar), subbase (lapispondasi bawah), base (lapis pondasi atas), dan surface (lapis permukaan). Untuk lapisan subbase,dan base dapat digunakan batu pecah (crushed rock). Salah satu material batu pecah tersebutadalah crushed limestone. Crushed limestone adalah limestone (batu kapur) yang telah melaluiproses crushing di pabrik untuk mendapatkan berbagai ukuran butir yang dibutuhkan dalamkeperluan desain.Tujuan studi ini adalah untuk menganalisis pengaruh ukuran butir terhadap parameter kompaksidan nilai California Bearing Ratio (CBR) material crushed limestone. Material crushed limestoneyang digunakan berasal dari daerah Padalarang, Jawa Barat. Ukuran butir equivalent dari materialcrushed limestone yang digunakan sebagai sampel uji antara lain adalah:2mm (SU1), 3mm (SU2)dan 4mm (SU3). Uji kompaksi di laboratorium menggunakan tata cara standard Proctor testdengan mengacu pada standar uji ASTM D 698. Uji CBR di laboratorium mengacu pada standaruji ASTM D 1883.Hasil penelitian menunjukkan bahwa rasio kenaikan maximum dry density, ?dry max SU2 dan SU3terhadap ?dry max SU1 berturut-turut adalah; 0.6% dan 1.9%, hal ini menunjukkan bahwapeningkatan ukuran butir equivalent dari 2mm ke 4mm tidak berpengaruh secara signifikanterhadap parameter ?dry max. Rasio kenaikan nilai CBR design SU2 dan SU3 terhadap CBR designSU1 berturut-turut adalah; 16.3% dan 32.7%. Hal ini menunjukkan bahwa semakin besar ukuranbutir equivalent material crushed limestone maka semakin tinggi nilai CBR design.


2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Anigilaje B Salahudeen ◽  
Ja’afar A Sadeeq

The study investigate the suitability of subgrade soil in Baure Local Government Area of Kastina State Nigeria for road construction. The strength properties of the  subgrade was improved using lime and cement. Several analysis including the particle size distribution, specific gravity, Atterberg limits, compaction characteristics, unconfined compressive strength and California bearing ratio tests were performed on natural and lime/cement treated soil samples in accordance with BS 1377 (1990) and BS 1924 (1990) respectively. Soil specimens were prepared by mixing the soil with lime and cement in steps of 0, 3, 6, and 9% by weight of dry soil in several percentage combinations. The Atterberg limits of the weak subgrade soils improved having a minimum plasticity index value of 5.70 % at 3%Lime/6%Cement contents. The maximum dry density (MDD) values obtained showed a significant improvement having a peak value of 1.66 kN/m3 at 9%Lime/9%Cement contents. Similarly, a minimum value of 18.50 % was observed for optimum moisture content at 9%Lime/9%Cement contents which is a desirable reduction from a value of 25.00 % for the natural soil. The unconfined compressive test value increased from 167.30 kN/m2 for the natural soil to 446.77 kN/m2 at 9%Lime/9%Cement contents 28 days curing period. Likewise, the soaked California bearing ratio values increased from 2.90 % for the natural soil to 83.90 % at 9%Lime/9%Cement contents. Generally, there were improvements in the engineering properties of the weak subgrade soil when treated with lime and cement. However, the peak UCS value of 446.77 kN/m2 fails to meet the recommended UCS value of 1710 KN/m2 specified by TRRL (1977) as a criterion for adequate stabilization using Ordinary Portland Cement.            Keywords: Weak subgrade soil, Lime, Cement, Atterberg limits, Maximum dry density, Optimum moisture content, Unconfined compressive strength, California bearing ratio


2021 ◽  
Vol 47 (1) ◽  
pp. 156-163
Author(s):  
Oluremi Johnson Rotimi ◽  
Bamigboye Gideon Olukunle ◽  
Afolayan Olaniyi Diran ◽  
B. Iyanda Olayinka ◽  
A. Bello Usman

Effect of spent calcium carbide (SCC) on index and strength properties of lateritic soil at differ- ent compactive efforts was assessed in this study as potential means of improving the geotechnical properties of the subsoil as well as disposing of SCC as waste. SCC was admixed with the soil using 0 to 10 % by dry weight of soil at an incremental rate of 2%. The following tests were carried out on the samples: specific gravity, Atterberg limit, particle size distribution, compaction, and California bearing ratio (CBR). Compaction and California Bearing Ratio (CBR) tests were carried out using British Standard light (BSL), West African Standard (WAS), and British Standard heavy (BSH) on both the natural and stabilized soil samples. From the investigation, atterberg limits show a reduction in the plasticity index with increasing content of SCC. The maximum dry density of the soil decreased with increasing SCC content and increased with an increase in compactive energies (BSL<WAS<BSH), while and optimum moisture content (OMC) increased correspondingly. Also, soaked and unsoaked CBR values of the stabilized lateritic soil showed an increase in strength with higher compactive effort, and SCC content up to 4% SCC addition and after that decreased in value. Based on these results, spent calcium carbide improved the geotechnical properties of this lateritic soil, and 4% SCC is recommended for its stabilization as subgrade material for pavement construction, thereby serving as an effective method of disposing SCC towards promoting a green and sustainable environment.


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