Prediction of Aggregate Impact Values and Aggregate Crushing Values Using Light Compaction Test

Crushing test and Impact test are very important to estimate strength and toughness characteristics of the road aggregate. Extensive experimental procedures and different sets of equipment are required for these types of aggregate testing. Therefore, the objective of the study is to investigate whether the light compaction test can be a suitable alternative for both these tests. For this experimental procedure, 60 aggregate samples were collected from different rock quarries spread along North-eastern states of India. The specifications of the aggregate samples are kept similar for all of these three test procedures. The result indicates a strong correlation of Light compaction values (LCV) with Aggregate crushing values (ACV) and Aggregate Impact Values (AIV). The R2 values for the relationship was found to be more than 0.9 for both these relationships. It indicates that the LCV can be used to closely predict the ACV and AIV. The root mean square error (RMSE) values estimated based on the actual and predicted values were also found to be low which further concrete the claim that light compaction test can be a suitable alternative for crushing test and impact test of the aggregates.

Optimization Design of Mix Proportion of Large Stone Permeable Mixture Based on Target Air Voids

Through theoretical analysis, this paper preliminarily puts forward the optimization design method of a mix proportion large stone permeable mixture based on target voidage. The optimized large stone permeable mixture is abbreviated as OLSPM (optimization large stone permeable mixture). On this basis, the asphalt content was verified by leakage analysis experiment, and the molding method was determined by comparing the volume parameter changes and the appearance of the specimen in the molding process of both a Marshall compaction test and rotary compaction test. The final experimental analysis results show that the asphalt content calculated by this method can meet the technical requirements of leakage loss. The rotary compaction method is the suitable molding method for indoor cylindrical specimens of OLSPM, and the voidage is used as the index to control the compac-tion times of OLSPM. Under the same voidage, OLSPM-25 has more fine aggregates and thus leads to a relatively large amount of asphalt. In addition, the content of 4.75–19 mm coarse aggregate in its coarse aggregate is also higher than that of LSPM-25.

Calibration of Drucker–Prager Cap Constitutive Model for Ceramic Powder Compaction through Inverse Analysis

Phenomenological plasticity models that relate relative density to plastic strain are frequently used to simulate ceramic powder compaction. With respect to the form implemented in finite element codes, they need to be modified in order to define governing parameters as functions of relative densities. Such a modification increases the number of constitutive parameters and makes their calibration a demanding task that involves a large number of experiments. The novel calibration procedure investigated in this paper is based on inverse analysis methodology, centered on the minimization of a discrepancy function that quantifies the difference between experimentally measured and numerically computed quantities. In order to capture the influence of sought parameters on measured quantities, three different geometries of die and punches are proposed, resulting from a sensitivity analysis performed using numerical simulations of the test. The formulated calibration protocol requires only data that can be collected during the compaction test and, thus, involves a relatively smaller number of experiments. The developed procedure is tested on an alumina powder mixture, used for refractory products, by making a reference to the modified Drucker–Prager Cap model. The assessed parameters are compared to reference values, obtained through more laborious destructive tests performed on green bodies, and are further used to simulate the compaction test with arbitrary geometries. Both comparisons evidenced excellent agreement.

Comparison of fly ash with Lapindo mud as a land stabilizer for landfill in Pasuruan–Indonesia

The paper discusses the comparison of fly ash with Lapindo mud as a land stabilizer for a landfill in Pasuruan, Indonesia. Land for landfills has a low level of stability due to the condition of garbage that has accumulated and undergoes a process of decay. This land condition is less favorable to support the construction of the building above it if one day the location is used for construction. Therefore, it is necessary to stabilize the soil first. The purpose of this study was to determine the effect of adding a mixture of TPA soil with fly ash and Lapindo mud. The method used by sieve testing and compaction of the specimens for each treatment consisted of a mixture of TPA soil with fly ash and TPA soil with Lapindo mud, while the percentages of fly ash and Lapindo mud to the dry weight of the original soil were respectively 0 %, 10 %, 15 %, and 20 %. The results showed that stabilization of the landfill with fly ash reduced the silt content while stabilization with Lapindo mud increased the levels of silt in the landfill so that fly ash was better than Lapindo mud for stabilization of the landfill. The specific gravity values for both stabilization mixtures increased equally. Based on the results of the standard compaction test for the addition of a mixture of fly ash, the OMC value decreases and the greater the value of dmaxs indicates that fly ash is good for landfill stabilization, while the addition of a mixture of Lapindo mud increases the OMC the smaller the value of dmaxs. For the direct shear test of the two mixed soils, the value of the internal friction angle (Æ) increased. The percentage value of the optimum mixture of mixed soil+fly ash is 14 % with an internal shear angle (Æ) of 38°, while the stabilization of landfill with Lapindo mud obtained the optimum mixture percentage value of 11 % with an internal shear angle (Æ) of 31°

Pengaruh Penambahan Serat Rami pada Tanah Terjun-Medan dengan Pengujian Standard Compaction, Triaxial Unconsolidated Undrained, dan Prediksi Balik dengan Plaxis 2D

Tanah mempunyai peranan yang penting dalam konstruksi. Daya dukung tanah wajib mampu menahan beban struktur di atasnya. Problematika tanah lunak yang sering dijumpai seperti kerusakan jalan perkerasan lentur maupun kaku, kelongsoran timbunan, kelongsoran lereng, dan penurunan tanah yang menyebabkan kerusakan struktur. Diperlukan inovasi yang ramah lingkungan dalam penanganan tanah lunak tersebut secara in-situ disamping dengan pertimbangan dari segi ekonomis, waktu, dan ketersediaan material. Penelitian bertujuan untuk mengetahui pengaruh penambahan serat rami pada tanah terhadap kekuatan geser dan kepadatan kering maksimum tanah. Penelitian ini menggunakan serat rami yang dicampurkan secara acak dengan tanah dengan kadar rami sebesar 1%, 2%, 3%, 4% dan 5% dari berat tanah kemudian dilakukan compaction test dan Triaxial UU. Pengujian Triaxial UU dilakukan untuk tanah dengan kandungan serat maksimum. Hasil penelitian ini yaitu kepadatan kering maksimum (ℽdmax) tanah mengalami penurunan seiring dengan penambahan serat rami dimana ℽdmax tertinggi sebesar 1,595 g/cm3 sedangkan ℽdmax terendah sebesar 1,438 g/cm3. Penambahan serat rami sebesar 5% menghasilkan peningkatan pada nilai kekuatan geser (cu) hasil pengujian Triaxial UU sebesar 477,1% dari 1,05 kg/cm2 menjadi 5,01 kg/cm2. Hasil pemodelan Triaxial UU dengan pemodelan harderning soil model pada program Plaxis 2D cukup mendekati dengan hasil pengujian laboratorim dengan hasil tegangan deviatorik yang relatif sama.

Experimental Study of Improving the Properties of Lime-Stabilized Structural Lateritic Soil for Highway Structural Works using Groundnut Shell Ash

This research considered the viability of groundnut shell ash (GSA) on lime-stabilized lateritic soil for highway structural works. Three samples of lateritic soil, named samples A, B, and C, were gathered from Idita-Mokuro, NTA-Mokuro, and ETF burrow pits, respectively, in Ile-Ife, Osun State, Nigeria. Preliminary tests were completed on the samples in their natural states and when stabilized with optimum lime. Engineering properties were performed while 2, 4, and 6 % GSA contents were added to the soil samples at optimum lime. The Atterberg limit tests showed a significant reduction in the plasticity index for samples A and C when stabilized with lime. Compaction test showed a decrease in the maximum dry density from 1,685 to 1,590 kg/m3 for sample A, 1,599 to 1,512 kg/m3 for sample B, and 1,396 to 1,270 kg/m3 for sample C on stabilizing with lime; the introduction of GSA to stabilized lime soil diminished the maximum dry density for all the soil samples, with sample A reduced to 1,435 and 1,385 kg/m3 at 2 and 4 GSA contents, respectively. The addition of GSA improved the engineering properties of lime-stabilized soils as the unsoaked CBR esteems expanded for all soil samples. At an optimum lime dosage, the addition of 2 % GSA expanded the triaxial shear strength from 60.43 to 188.36 kN/m2 for sample A and, at 4 % GSA content, both soil samples B and C increased from 19.19 to 201.48 kN/m2 and 30.62 to 111.65 kN/m2, respectively. Conclusively, GSA improved the toughness and strength of lime-stabilized lateritic soil for highway structural works.

Experimental and Statistical Study on Black Cotton Soil Modified with Cement–Iron Ore Tailings

The investigation focused on the response of black cotton soil (BCS) treated with mixtures of iron ore tailings (IOT) and cement to varying compaction effort (CE). Preliminary tests showed that the un-treated soil is A-7-6 (22) on the basis of AASHTO protocols of classification while the USCS (Unified Soil Classification System) guidelines placed the soil in CH group. Laboratory tests carried out included cation exchange capacity, CEC, Specific gravity (Gs) and compaction test. Three compaction energy levels (i.e., British Standard heavy (BSH), West African Standard (WAS) and British Standard light (BSL)) were adopted for the compaction test. Test results showed that CEC decreased; Gs and MDD increased while OMC also decreased for all cement contents considered when admixed with the different IOT contents up to 10 % IOT by the soil dry weight. MDD values of 1.58, 1.59, 1.62, 1.64, 1.64 and 1.66 Mg/m3 were noted for 1% cement and 0, 2, 4, 6, 8 and 10% IOT content compacted with BSL energy. Also, OMC values of 21.2, 20.8, 20.5, 20, 20.3 and 20.2% were noted for 1% cement and 0, 2, 4, 6, 8 and 10% IOT content compacted with BSL energy. Same trend was noted for higher cement concentrations and compactive efforts. Regression models for MDD and OMC, considered as dependent variables while C (cement content), CE, IOT, Gs and PF (percentage of fine) as independent variables were developed using software (Mini-tab R15). The result of regression analysis shows that the independent variables considered greatly influence the dependent variables. ANOVA (Analysis of variance) was use to establish the levels of contributions of cement and IOT to the improvements recorded. Therefore, black cotton soil optimally treated with 4% cement 10% IOT blend and compacted with BSH energy is recommended for soil remediation or geotechnical engineering applications. Keywords— Compaction effort, iron ore tailings, black cotton soil (BCS), Analysis of Variance, regression analysis.

Geology and geotechnical investigations of part of the Anambra Basin, Southeastern Nigeria: implication for gully erosion hazards

Background Geologic and geotechnical conditions of soils where Nanka and Ajali Formations outcropped in Anambra Basin, Southeastern Nigeria were investigated and accessed. This was done using detailed mapping and mechanical soil laboratory tests to unravel the genesis and continued expansion of gully erosion in the study areas. Results Field study revealed that gully erosions are more pronounced in the study area with poor vegetation cover and a high degree of slope steepness. Grain size analysis revealed that the soils of the Nanka Formation have an average sand content value of 90.90% (sandy) and silt content value of 3.0% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 5.29%. The soils have an average cohesion value of 0.30 kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.67 × 10–3 cm/s. The compaction test further revealed that the soils are loosely compacted. The soils for the Ajali Formation have an average sand content value of 95.10% (sandy) and silt content value of 1.43% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 2.70%. The soils have an average cohesion value of 0.30 kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.70 × 10–3 cm/s. The compaction test revealed that the soils are loosely compacted. Conclusion After field surveys and laboratory analyses, it was found that the gully erosions have been developing respectively on steep slopes and non-vegetated areas, and their genesis facilitated by the cohesionless and very permeable nature of the sandy formations. Following those key findings, it was proposed many practices (agronomic and engineering mainly) that can help mitigate the formations as well as the expansion of this very damaging hazard type. The potential implications of these gully erosion include damaging of buildings, residential houses, bridges, and roads, loss of farmland and vegetation, isolation of villages and towns, increased migration of inhabitants as well as degradation of agricultural fertile land.

Geology and Geotechnical Investigations of the Anambra Basin, Southeastern Nigeria: Implication for Gully Erosion Hazards

BackgroundGeologic and geotechnical conditions of soils where Nanka and Ajali Formations outcropped in Anambra Basin, Southeastern Nigeria were investigated and accessed. This was done using detailed mapping and mechanical soil laboratory tests to unravel the genesis and continued expansion of gully erosion in the study areas. ResultsField study revealed that gully erosions are more pronounced in the study area with poor vegetation cover and a high degree of slope steepness. Grain size analysis revealed that the soils of the Nanka Formation have an average sand content value of 90.90% (sandy) and silt content value of 3.0% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 5.29%. The soils have an average cohesion value of 0.30kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.67x10-3 cm/sec. The compaction test further revealed that the soils are loosely compacted. The soils for the Ajali Formation have an average sand content value of 95.10% (sandy) and silt content value of 1.43% (low fine portions). The plasticity index of the fine portions indicates that the soils are weak plastic, with a mean value of 2.70%. The soils have an average cohesion value of 0.30kg/cm2 indicating a very weak cohesion. The soils are highly permeable; with an average value of 2.70x10-3 cm/sec. The compaction test revealed that the soils are loosely compacted.ConclusionsAfter field surveys and laboratory analyses, it was found that the gully erosions have been developing respectively on steep slopes and non-vegetated areas, and their genesis facilitated by the cohesionless and very permeable nature of the sandy formations. Following those key findings, it was proposed many practices (agronomic and engineering mainly) that can help mitigate the formations as well as the expansion of this very damaging hazard type. The potential implications of these gully erosion include damaging of buildings, residential houses, bridges and roads, loss of farmland and vegetation, isolation of villages and towns, increased migration of inhabitants as well as degradation of agricultural fertile land.