California Bearing Ratio Tests Research Articles

Stabilization of Clayey Soil using Gypsum and Calcium Chloride

The engineering strength properties of expensive soils (clayey soil) such as compaction characteristics and bearing capacity can be improved by stabilization process of the soil. These properties can be improved by controlled compaction using the mechanical equipment’s or by addition of suitable admixtures like cement, fly ash, lime, gypsum or by reinforcing the soil with shredded tyre, crumb rubber, plastic waste etc. But gypsum is used now a days to enhance the geotechnical properties. So, in this research paper gypsum and calcium chloride has been used to improve the various strength properties of natural soil. The objective of this research paper is to examine the strength properties of natural clayey soil reinforced with different percentage of gypsum by the weight of soil and fixed percentage of calcium chloride(Cacl2) as a binding material. A series of Standard Proctor tests(for calculation of MDD and OMC) and California Bearing Ratio (C.B.R) tests are conducted on both raw clayey soil and reinforced soil with different percentages of gypsum (2%, 4%, 6% and 8%) by weight and with fixed percentage of calcium chloride (0.75%). A comparison between properties of raw clayey soil, raw clayey soil mixed with gypsum and raw clayey soil mixed with gypsum and calcium chloride (CaCl2) are performed. It is found that the properties of clayey soil mixed with gypsum and calcium chloride (CaCl2) are suitably enhanced.

Strengthening the clayey gravel and sand soils for Subbase course highway using different waste materials

The stabilization of clayey gravel and sand soil used in construction of subbase course pavement highway is one of the engineering solutions in order to increase structural capacity of underneath pavement layers. There are many sorts of soil stabilization which are classified into mechanical and chemical methods. Recently, there has been an increasing social concern about the issue of waste management, by production industrial waste and waste disposal. This project presents the study of the influence of waste ceramic dust (WCD) on strength of clayey gravel and sand materials used in construction of subbase course. The subbase collected locally was mixed with waste ceramic dust from (0 to 25%) by weight of dry soil. The target of this study is to clear that waste is often used as filling and reinforcement and for this reason California Bearing Ratio test (CBR) was conducted to research the strength of waste ceramic and plastic strip of subbase material. The application of plastic waste in various forms is one among the emerging areas of ground improvement technique and there are economic and eco-friendly advantages. A detailed analysis of their results depicts that it is often utilized in the fields effectively and economically as reinforcing materiel. Plastic strips with dimensions (12 mm × 6 mm) are mixed with soil containing the optimum proportion of ceramic dust and California bearing tests are conducted. The effect of waste plastic strip (WPS) content is 0.5% to2% (by weight of sub base material) on the CBR of strip reinforced subbase was studied. The ratio is decided by changing its length and width. From the CBR on soil with and without plastic reinforcements, it had been found that after reinforcement the soil gained its strength appreciably. The best percent of waste ceramic dust was (20%) with waste plastic strip is (1%) which gave higher percent of CBR.

Investigation of Pindan soil modified with polymer stablisers for road pavement

Road failures are often caused by structural weaknesses, and particularly unsealed roads are vulnerable to water as water easily flows into road structures. Moisture susceptibility of materials is an important aspect when pavements are designed as moisture can weaken bonds between aggregates. Pindan soil is a red soil, known as a soft and moisture sensitive soil. Polymer stabilisers have been proved that they can improve soil mechanical properties by providing an internal waterproofing. Studies of the polymer-Pindan soil stabilisation have been focused on engineering performances, but literature shows little information on the fundamental information of Pindan soil. This project focuses on fundamental information of Pindan soil and its improved performances using polymer stabilisers. Plastic index, specific gravity and particle size distribution were tested to obtain the basic properties. Compaction, Unconfined Compressive Strength and California Bearing Ratio tests were performed to determine the mechanical properties. The chemical property was examined using X-ray diffraction. Furthermore, the waterproof effect of the polymers on the stabilised Pindan soil was investigated from capillary rise tests. In addition, the mechanical properties of individual soil grains were investigated using nanoindentation tests. The materials used for this investigation primarily consisted of Pindan soil collected in Broome, Western Australia, and three polymer products manufactured in Australia. Based on the results, it is evident that the failure behaviour, strain and strength as well as the basic properties of the soils are affected and changed by the Polymer stabilisers. The type of polymer influenced the optimum moisture contents and strengths rather than the amount of polymer. Similarly, Nanoindentation technology provided various information such as elastic modulus, hardness, packing density, stiffness, cohesion and fracture toughness of soils at nano-scales. Polymers can reduce water ingress and minimise moisture in the pavement structures. Thus, the structures can maintain its strength and prevent deformation, which will increase the lifetime of unsealed pavements.

Prediction of the California bearing ratio from some field measurements of soils

In this study, the fast and safe predictability of the California bearing ratio (CBR) from some important soil parameters that can be obtained easily and cheaply was investigated. Within the scope of this study, the CBR values of 21 different soils in different regions of Sivas province (Turkey) were determined in situ by CBR tests. Then, standard penetration tests (SPT) and ground vibration measurements were conducted on the same soils. At the same time, some physical properties of the soils were determined as a result of field and laboratory studies. Regression analyses were carried out in order to develop correlations between the CBR, and field and laboratory study results. Significant and highly correlated relations between the CBR and peak particle velocity, blow number (SPT-N value), water content (w) and dry unit weight(γd), were obtained. Prediction performance of all proposed equations were tested by using the root mean square error (RMSE) and variance account for (VAF) indices, and particularly, correlations obtained between the CBR – ground vibration and CBR – standard penetration values were observed to have high prediction performance. Good performance indices (correlation coefficients, RMSE, VAF) indicate that the CBR values of soils can be used for initial assessment.

Fuzzy-Based Model for Predicting Strength of Geogrid-Reinforced Subgrade Soil with Optimal Depth of Geogrid Reinforcement

A fuzzy logic (FL)–based modeling approach is employed for geogrid-reinforced subgrade soil of unpaved roads. A review of the literature reveals that fuzzy logic has not been used for predicting the behavior of geogrid-reinforced subgrade. This paper presents FL-based two models with fuzzy Triangular and Gaussian membership functions for input and output variables. It consists of eight input parameters/factors, namely, reinforced/unreinforced section, depth of reinforcement, liquid limit, plastic limit, plasticity index, optimum moisture content, maximum dry unit weight, and soaked/unsoaked condition, and California bearing ratio (CBR) as an output parameter. The fuzzy rules are deduced from the experimental data. The laboratory CBR tests were performed on the subgrade soil reinforced with geogrid. The precision of models was examined by comparing the predicted CBR values with the experimental CBR values for Triangular and Gaussian membership functions. The sensitivity analysis reflects a set of dominant parameters. The results indicated a significant improvement in the CBR value of geogrid-reinforced subgrade soil due to the inclusion of geogrid. The range for optimal depth of geogrid reinforcement is found to be 36 to 60% of the thickness of the soil layer. The potentialities of FL were found to be satisfactory.

A study on the effects of groundnut shell ash on strength characteristics of soil

This study investigated the effect of groundnut shell ash (GSA) on the strength of selected lateritic soils, with a view to determining the optimum percentage of GSA that will give the best strength properties of the soils. Soil samples were collected from two different borrow pits and identified as sample A and sample B respectively. Preliminary tests (Natural moisture content, specific gravity, grain size analysis, Atterberg limit) and engineering tests (compaction and unsoaked California bearing ratio (CBR)) were conducted on the soil samples in their natural state. GSA was then added to the soils at 2 %, 4 % and 6 % proportions. Atterberg limits, compaction and unsoaked CBR tests were conducted for each addition of GSA. The results showed that there was much improvement in the properties of the soils, with values of plasticity index (PI) reducing from 23.02 % (at 0 % GSA) to 12.55 % (at 6 % GSA) for sample A; and 35.14 % (at 0 % GSA) to 2..54 % (at 6 % GSA) for sample B. It was also observed that addition of GSA generally caused reduction in optimum moisture content (OMC) with an increase in corresponding maximum dry density (MDD). For sample A the maximum value of unsoaked CBR (17 %) was obtained at 2 % GSA, while for sample B, maximum CBR value (4 %) was obtained at 4 % GSA. It was concluded that GSA could be used to significantly improve the strength of lateritic soil.

Geotechnical Properties of Anthropogenic Soils in Road Engineering

The construction of a roads network consumes high amounts of materials. The road materials are required to fulfill high standards like bearing capacity and low settlement susceptibility due to cyclic loading. Therefore, crushed aggregates are the primary subbase construction material. The material-intensity of road engineering leads to depletion of natural resources, and to avoid it, the alternative recycled materials are required to be applied to achieve sustainable development. The anthropogenic soils (AS), which are defined as man-made unbound aggregates, are the response to these requirements. For the successful application of the AS, a series of geotechnical laboratory and field tests were conducted. In this article, we present the set of 58 test results, including California Bearing Ratio (CBR) bearing capacity tests, oedometric tests, and cyclic CBR tests, to characterize the behavior of three AS types and to compare its reaction with natural aggregate (NA). The AS tested in this study are recycled concrete aggregate (RCA), fly ash and bottom ash mix (BS), and blast furnace slag (BFS). The results of the tests show that the AS has similar characteristics to NA, and in some cases, like compression characteristic, RCA and BFS behave a stiffer response to cyclic loading. The test results and analysis presented here extend the knowledge about AS compressibility and AS response to cyclic loading.

Chemical Stabilization of Black Cotton Clay and Laterite Soil Using Drycon Powder for Suitability as Construction Materials

This paper used drycon powder (DP) as stabilization additive for improving the engineering properties of problem soils, specifically, black cotton clay (BCC) and laterite soil (LS), for use as a road construction material. The study was carried out in some parts of the Greater Accra Region of Ghana, through the conduction of index properties tests such as gradation, Atterberg limits, California bearing ratio (CBR), Compaction characteristics and X-ray diffraction (XRD) on the problem soils. CBR, Atterberg limits and environmental quality tests were specifically conducted on DP stabilized soils for comparative analysis. Gradation results revealed 38% fines for BCC and 14% fines for LS. X-ray diffraction analysis revealed the presence of quartz and montmorillonite in BCC, and quartz and kaolinite in LS. Generally, the results of the various tests conducted revealed that DP has the potential of improving the engineering properties of problem soils with significant strength improvement. It can also be inferred from the results that, DP is environmental friendly soil stabilizer.

Geotechnical properties of recycled construction and demolition materials for filling applications

Abstract Modern societies make a hard effort to improve the sustainability of resources due to enhanced environmental sensitivities in nowadays. This paper investigates the usability of recycled construction and demolition materials as an alternative to virgin aggregates in geotechnical applications such as the filling. The physical and geotechnical properties of recycled construction and demolition materials were determined by laboratory tests (i.e. sieve test, flatness test, Los Angeles abrasion test, water absorption test, pycnometer test, modified compaction test, California bearing ratio test, unconfined compressive strength test and resilient modulus test) and a comprehensive laboratory evaluation was carried out. Moreover, similar tests were conducted with a type of high-quality virgin aggregate material frequently used in fillings. The results of the tests conducted on construction and demolition materials were compared with results of the tests conducted on both virgin aggregate and different recycled aggregates which are accepted as an alternative to virgin aggregates used in the filling in the literature. Results of the tests conducted on construction and demolition materials were also evaluated according to the limit values in technical specifications of highway administrations of various countries. As a result of this study, it has been concluded that construction and demolition materials can be a good alternative to virgin aggregate used in the filling provided that it is taken measure against excessive water absorption value.

Experimental investigation of bottom ash as a capable Soil Stabilizer

The development of infrastructure in India is rapidly growing. These structure demands adequate soil as foundation/subgrade but in India where expansive soil cover 51.8 hectare land surface nearly. Stabilization of these expansive is the priority of engineers. Where on the other hand bottom ash from a thermal power plant is directly dumped which contaminatesthe environment. In soil stabilization, a stabilizer is added to soil in optimum quantity to achieve maximum dry density and have minimum penetration. In this study bottom ash’s potential is examined as a soil stabilizer and compared with non-conventional stabilizer. Soil is modified with bottom ash at dosages of 10%, 20%, 30% and 40% to inspect the various engineering properties. Atterberg limits (LL, PL, and PI), Compaction characteristics (OMC &MDD) and California bearing ratio test are performed and compared with nano-polymer modified soil samples. Results show that bottom ash can be utilized as a stabilizer for road construction.

Evaluation of Recycled Demolition Waste Aggregates for base and sub-base use in Roads

Recycling of debris to obtain the recycled aggregates for sub-base materials in road construction is a foremost application to be promoted to gain economical and sustainable benefits. In this study, different types of demolition waste samples were subjected classification tests such as chemical tests, particle size distribution, compaction, California Bearing Ratio (CBR) test. The experimental work included fourteen samples at different weight were taken to determine the proportion of demolition waste subbase. The result of sampling tests were compared with the general specifications for roads and bridges (SORB/R6), it was f that the effect of SO3, gypsum and total soluble salt (TSS) parameter on the demolition waste subbase were low and the gradation of demolition waste subbase was class A. the California bearing ratio CBR value was 37% with maximum dry density 2035 kg/m3, in addition the average compaction test was 95.98%, whereas the optimum moisture content of the study materials was 8%.

Influence of Jute Fibre on CBR Value of Expansive Soil

Construction of structures on expansive soil is highly risky due to its susceptible behavior towards differential settlements. Different soil stabilization techniques including soil reinforcement have been adopted to improve the properties of the unsuitable soils. In this present study, randomly distributed jute fibres have been used to improve geotechnical properties of expansive soil collected from South Delhi (India). California Bearing Ratio (CBR) tests were carried out on the expansive soil blended with jute fibres. Jute fibres of length 10 mm and 30 mm were included in different percentages viz. 0.25, 0.50, 0.75, 1.00, 1.25 and 1.50 by the dry weight of the soil. The test results indicate that the inclusion of randomly distributed jute fibres significantly improves the CBR value of the soil. The Optimum value of fibre content is found to be 1.25%. An improvement of 226.92% in CBR value of the reinforced soil as compared to unreinforced soil has been observed at the optimum jute fibre content. Since Jute is agricultural waste, the present study provides a cost-effective solution to problematic clayey soils.

Experimental Study of Natural Materials Utilization as a Stabilization Agent on Soft Soil

Chemical soil stabilization is known as the most economical method compared to others. The development of stabilization materials has led to studies of the utilization of natural materials and waste materials to replace cement and lime which has become the most popular binder agent ever known. This research utilizes natural minerals such as overboulder, zeolite and Palm Oil Fuel Ash (POFA) as its binder agents. The amount of natural material varies at intervals 3% - 15% by the weight of soil. Additional of natural materials is done to increase bearing capacity as a subbase layer, which is based on FHWA standards CBR minimum is 20%. California Bearing Ratio (CBR) tests were carried out to see the effect of each material for increase bearing capacity of soft soil. Curing periode is varies at 7 days, 14 days and 28 days. The results shows, by adding natural minerals such as overboulder, zeolite, and POFA increasing the CBR value up to 5 times, 6 times and 5 times compared to untreated soil and close to the CBR value of cement stabilized soil. Referring to FHWA standards, we can conclude that natural materials can be used for stabilization materials on subbase layer.

Influence of Fly Ash Addition on Behavior of Soft Clayey Soil

This paper investigates the impact of the fly Ash addition on the Geotechnical properties of soft soil as well as chooses the optimum percentage added of fly ash. To understand the behavior of fly ash mixed with soil, a number of laboratory experiments testing conducted on clayey soil-fly ash mixture in several percentages (5,10,15,20,25, and 30%) as Atterberg test, Specific gravity test, compaction test, California Bearing Ratio (C.B.R) Test, Unconfined Compressive Strength (UCS) Test, Consolidation Test. Test results indicate rising in plastic limit and liquid limit as fly ash adding. Specific gravity decreased essentially by adding fly ash. Whereas there was falling on the Dry unit weight value with the contract to the decreasing in the water content. The CBR and UCS values were increased with increasing fly ash content. 20% was the optimum fly Ash content. This study also benefits the effective use of fly ash and thus a cost-effective method for improving the soil properties.

Pemanfaatan Geopolimer Abu Terbang Sebagai Pozzolanic Tanah Lempung Untuk Material Tanah Dasar Perkerasan

California Bearing Ratio (CBR) is one of a method for determining soil bearing capacity. Extraction of industrial disposal to be used as material for road pavement construction is still lacking. This research aims to determine changing CBR values due to the fly ash addition in clay under conditions with or without curing and soaked. Samples curing for 28 days were done in two conditions firstly, curing in mold and wrapped with plastic. Secondly, wrapped with plastic off mold. Looking at the CBR test results, plasticity index, density and specific gravity (Gs) is decreased. The addition of fly ash rises the value of the optimum water content (OMC). CBR value increased due to the addition of fly ash, a significantly increase occurred in the fly ash addition by 15%. Curing method uses different CBR values, where curing using mold has a high CBR value. In soaked CBR test, the CBR value varies due to the characteristics of the fly ash and clay which absorbed water. Water absorption varies depend on the percentage of the mixture of fly ash content and clay. The width variance of moisture content with OMC, because water absorption, affect to value of CBR. Samples with moisture content is more close to OMC the CBR value is more bigger

Influence of Geosynthetic Reinforcement on Unpaved Roads Based on CBR, and Static and Dynamic Cone Penetration Tests

Dynamic cone penetrometer has been used widely as a pavement evaluation technique for many years. Unpaved roads constructed on weak soil subgrade are frequently subjected to severe damage and hence, they require regular maintenance and repair. One of the main stabilization methods of improvement of the serviceability of these roads is to reinforce them with geosynthetics (geotextile/geogrid). Field experiments were conducted on unpaved test sections reinforced with geotextile and geogrid, with the potential use of dynamic cone penetrometer (DCP) and digital static cone penetrometer (SCP) to assess benefits of geotextile and geogrid reinforcement. Laboratory California bearing ratio (CBR) tests were also conducted on subgrade–aggregate section and the effect of geosynthetic reinforcement was investigated by placing the reinforcement layer at the interface of the base course layer and weak subgrade. Digital SCP was used to measure the load–displacement behavior of geosynthetic-reinforced test section in the field. The field test results of DCP were expressed in terms of dynamic cone penetration index (DCPI, mm/blow), defined as the penetration depth of the cone per hammer blow and recorded along with the depth profile. A decrease in DCPI value was observed for the reinforced test sections as compared to the unreinforced test section. DCP results were able to detect transition zone and significant change in the strength of unpaved test section along with penetration depth. The field results indicate the greater resistance to penetration in the geosynthetic-reinforced test section and the penetrometer resistance increases with the depth. Higher penetration resistance offered by the geotextile has more contribution to the performance improvement of the test section.

Field Evaluation of Coir Geotextile Reinforced Subgrade for Low Volume Pavements

ABSTRACT This investigative study focuses on the response of full scale coir reinforced low volume roads when subjected to static loading. The test track of 1.736 km consists of a control section and eight reinforced sections including two types of coir geotextiles and subbase with varying thickness. An assessment of the general behavior of coir geotextile-reinforced sections, to static plate load tests, California Bearing Ratio tests, geogauge and dynamic cone penetration tests is done for evaluation. The study summarizes the results of the executed tests on the reinforced test track in comparison to the unreinforced one. The results reveal that the geotextile with higher apparent opening size is not as good as that of the finer mesh geotextile. A maximum of 112% improvement in the elastic modulus of subgrade is achieved by using a woven coir geotextile of 740 g/m2 mass per unit area whereas 70% increment is attained while using an alternate geotextile of 365 g/m2 mass per unit area. The elastic modulus values are determined from the various field tests and the overall damage analysis is carried out using KENPAVE software. From the analysis, it is noted that an appreciable decrease in the aggregate layer thickness is achieved by using coir geotextile as reinforcement. Use of coir geotextiles in pavements as a reinforcement can therefore help in reducing the demand and consumption of fast-depleting natural resources.

Effectiveness of crumb rubber for subgrade soil stabilization

The properties of subgrade soil are important in the pavement design as its main function is to support the load transmitted from overlying pavement layers. Subgrade must have sufficient strength and stability even under bad traffic and climate conditions. Soil with good qualities should be used as subgrade but not all soil possesses the required abilities as there are some locations that have poor qualities of in-situ soil. The stabilization of soil can be used to improve the poor subgrade; hence it may reduce the thickness of pavement design and also increase life of the pavement. In this study, soil stabilization using crumb rubber is the alteration of subgrade soil as the properties of crumb rubber are lightweight and high shear strength. Moreover, it can also reduce the improper tyre’s disposal problem and pollutions. The soil used are collected from a landslide site located near to Mengkuang Dam in Seberang Perai Tengah, Penang in order to investigate the performance of subgrade soil stabilized with 2%, 4%, 6% and 8% of Crumb Rubber (CR). A series of laboratory testing of unsoaked and soaked (4 days) California Bearing Ratio (CBR) test have been performed to evaluate the best percentage of CR which fulfilled the JKR specification for subgrade. The results show that all mixtures; M2 (2% CR), M3 (4% CR), M4 (6% CR), and M5 (8% CR) are fulfilled the subgrade requirement according to the Public Works Department Malaysia (JKR) standard specification for road works where the CBR value must achieve more than 5%. The mixture with 4% CR (M3) shows the highest unsoaked and soaked CBR values, thus, the 4% CR is recommended to be implemented for subgrade soil stabilization.

Stabilisation of Sohar’s Sabkha soil using waste gypsum plasterboard

Sabkha soil are salt-encrusted desert flats typically found in arid regions. Construction developments on naturally occurring Sabkha soils are usually problematic. This study examines the properties of Sabkha soil obtained from Sohar city of Oman. The Sabkha soil samples were further treated with Gypsum obtained from waste plasterboards at varying percentages of 3, 6, 9 and 12 with a view to stabilising the soil. From the results, Sohar Sabkha soil is a poorly graded sand (SP) with AASHTO classification of A-2-7(0), therefore, it is unsuitable for supporting infrastructures in its natural form. The pH test confirms the reaction between Sabkha and Gypsum, while both the compaction and unconfined compression strength (UCS) tests revealed the optimum percentage of gypsum required to enhance the properties of Sabkha soil to be 6%. The California Bearing Ratio (CBR) test yielded a 33.3% increase in CBR value for Sabkha treated with 6% of Gypsum over untreated Sabkha. Overall, a better understanding of sabkha soil and the confirmation of the potential use of Gypsum for its stabilisation was achieved in this study.

Mechanical Properties Improvement of Clays Using Silica Sand Waste and Dust Sand Foundry Waste

The increase of industrial waste and many road damages due to unstable subgrade invite the research on soil additives made from waste treatment as stabilizers to improve the mechanical value of clay. This study used California Bearing Ratio Test based on the ASTM standard for mechanical properties testing of clay. The soil stabilization method was carried out by mixing the clay with Silica Sand waste and Dust Sand Foundry waste in a predetermined composition. California Bearing Ratio value of 2.5 mm penetration showed a significant increase of 47.9% from the original clay in the composition of the waste 5% Silica Sand and 5% Dust Sand Foundry.