INVESTIGATION OF THE INFLUENCE OF COW DUNG ASH AS FILLER AND POLYETHYLENE TEREPHTHALATE AS BITUMEN REPLACEMENT IN ASPHALT CONCRETE

This study investigated the influence of Cow Dung Ash (CDA) and Polyethylene Terephthalate (PET) as partial replacement of filler and binder respectively on the volumetric and Marshall Properties of asphalt concrete in separate mixes. In one mix, the filler was partially replaced with CDA at 4, 8, 12, 16 and 20% while for the other mix, the bitumen was partially replaced with PET at 3, 6, 9, 12 and 15 %. Asphalt briquettes were produced in accordance with marshal procedure for wearing course of medium traffic roads and marshal stability, while properties of the mixes were obtained from the flow and volumetric parameters. Results showed that replacing the filler between 4% and 8% with CDA has the potential for use in asphalt concrete. Also, for mixes with PET replacement, percentages between 6 and 15% can be considered for wearing course of medium trafficked roads

Comparative Analysis of Cement and Lateralite on the Engineering Properties of Niger Delta Soils for Pavement Construction

This is the final published version. It first appeared at http://sciencedomain.org/abstract/9224.This study investigated the effect of cement and lateralite in improving some engineering properties of Niger Delta soils, classified as clayey soil, silty/clayey sand, and fine sand. Cement had very good effect in reducing the plasticity of the clayey soil and the silty/clayey sand but increased the plasticity of the fine sand, and all the samples had increased soaked CBR and UCS at 28 days especially with 6% and 8% cement contents. 14% lateralite content had the best effect on the silty/clayey sand in reducing the plasticity and increasing both the CBR and UCS. However, no positive effect on the plasticity indices was noticed for the clayey soil and the fine sand, but appreciable increases in their unsoaked and soaked CBR and UCS at 28 days curing. The applications of cement (6% and 8%) and 14% lateralite would make the stabilized soils applicable as sub-base and base materials.The sponsorship of the PhD program of the first author by Schlumberger Faculty for the Future Foundation at the University of Cambridge, United Kingdom and the funding by Cambridge- Africa Alborada Scheme of this study which formed part of the PhD research are acknowledged

USE OF DRILL CUTTINGS ASH AS STABILISING AGENT FOR SELECTED NIGER DELTA SOILS FOR ROAD CONSTRUCTION

his study investigated potential of the use of Drill Cuttings Ash (DCA) in the stabilisation of Niger Delta soils for road construction. Most of the in-situ soils encountered in the region are fine-grained and highly plastic that would require special treatment. Four soil samples were obtained and the following tests were carried out: classification, compaction, California Bearing Ratio (CBR), and Unconfined Compressive strength (UCS). Dry DCA quantities ranging 2 – 8 percentages by weight of the soil was added to the air-dried soils for the stabilisation process. They were classified as A-6 (clayey soil), A-2-6 (clayey sand), A-3 (silty fine sand), and A-4 (silty clay soil). Generically, the unstabilised soils were fine-grained having low to medium plasticity, with low shear strength. Other results showed that 6% DCA content caused improvement in the texture, plasticity, and dry density of the clayey soil, while its CBR and UCS parameters compared favourably well with the unstabilised soil values. Also, there was increase in CBR value of the clayey soil after soaking for 24 hours. DCA increased the plasticity of the clayey sand, silty fine sand, and silty clay soil, and there was no substantial improvement in their strength properties. These results showed that DCA would be useful in improving clayey soilswhich are known to be prone to excessive swelling and difficult to handle during construction especially after heavy rainfall.     &nbsp

ASSESSMENT OF THE MICRO-STRUCTURE OF COMPACTED SOILS USING VARIED COMPACTIVE EFFORTS: A CASE STUDY OF SOME SELECTED AREAS IN PORT HARCOURT, NIGERIA

This research studies the effects of varying British standard heavy and British standard light compactions on the resulting micro-structures of soils using digital microscope. Three soils classified as A-6, A-7-6, and A-2-7 using AASHTO classification system were analysed. The initial properties tests and moisture- dry density relationship were carried out in accordance to British standard 1377 of 1990. The liquid limits ranged from 50.5% to 34.7% using the Casagrande liquid limit apparatus, plasticity index ranged from 22.3% to 12.4% and natural moisture content ranged from 24.3% to 21.2%. The lower the plasticity index the higher the maximum dry density for both degrees of compactions. From the micro-structural analysis, there was evidence of lines of shear at the wet-side of optimum moisture for all compactions and that the presence of these lines is high for soils of lower plasticity index at low compaction energies. At higher compaction effort, there was closer inter-particle aggregation of grains than at lower compaction efforts. The voids at the optimum moisture are smaller compared to those at the extremes of optimum, with voids on the wet-side of optimum larger than those at the dry side of optimum moisture for both compactive efforts. Thus, the micro-structure of the compacted soil revealed that the degree of compaction influences the degree of compactness of gains, the average dimension of voids, and the occurrence of thin lines of shear in their structure

STABILISATION OF NIGER DELTA FAT CLAY WITH BLEND OF BINDERS FOR SUBGRADE APPLICATION (PART 3) - TRIAL STABILISED ROAD SECTIONS IN SAMPOU, NIGER DELTA

The field performance of subgrade fat clay stabilised with additives and cement (PC) was evaluate by constructing trial sections along Odoni-Agbere road in Sampou, Bayelsa state. The blends mixed with the subgrade used in the study were, Drill Cuttings Ash (DCA)-PC (1:1), sand-PC (4:1), and lateralite-PC (2:1). Comparison of the dry density of cored stabilised samples with the laboratory samples showed that 100% compaction was achieved in the field for all the sections. Dynamic Cone Penetrometer (DCP) and field plate loading tests were used to determine the in-situ California Bearing Ratio (CBR) and settlement respectively. The in-situ CBR of the unstabilised and stabilised sections exceeded the targeted 15%. However, the in-situ CBR of the unstabilised section could be compromised if the soil is excessively manipulated and excess water is present. The percentage increase in settlement after two cyclic loading operations for the stabilised section ranging from -17 to 7%. This study revealed that the stability of the stabilised sections could be ensured if they are sealed on or before the 45th day after construction