Engineering

In this study, interface frictional resistance between organic soil and some of construction material was investigated. Construction materials used in this work are concrete, metal, and wood. Interface friction angle were determined for three different water contents values of organic soil dry, 25%, 50%, and 75% respectively. Different face roughnesses were tested for different water content. All tests were carried out using direct shear test device. Three different normal forces were used and shear stress at 10% strain rate was taken as maximum shear stress. Test results showed that water content of the organic soil, material type, and surface roughness should be considered while selecting interface friction angle between organic soil and construction materials.

This paper discusses the results of a series of direct shear test that were undertaken to investigate the behaviour of organic soil with granular soil column. The tests focused on effect of diameter of granular column in organic soil. Water content of the organic soil was kept constant for all tests. It was 125% that is liquid limit value. Four different column diameters were used. Sand used in the test is poorly graded and passing the No. 5 sieve and retaining on sieve No. 40 sieve. Shear strength properties of the samples were determined from direct shear  test. Loading was performed under undrained condition. Test results showed that ratio of sand column area to organic soil (S/O) are an important factor effecting shear strength properties of improved organic soil.

In this study, effect of water content, density, and sand content on shear strength parameters of organic soil were investigated. For this purpose, three sets of tests were carried out in the laboratory. In the first set, water content of the samples was changed at same density. In the second set, water content was kept constant but density was changed. In the third set different percent of sand by weight was mixed with organic soil.  Direct shear test was used in all tests. Test results showed that water content, density, and sand content effects shear strength of organic soil.

In this study, effect of different sand content on compaction properties of organic soil was investigated. Organic soil used in the study was taken from Sakarya region, Turkey. Compaction test was carried out with standard 2.5 kg hammer. Five different sand content was used that are 10%, 20%, 30%, 40% and 50%. Test results showed that sand content has an important effect on both dry density and optimum moisture content. When the sand content incresed in the organic soil optimum moisture content reduced and the maximum dry density increased.

In this study, the effect of sand content on compaction,
shear strength, and compressibility of fibrous peat
was investigated. The sand used for the study is rounded
and poorly graded passing 2-mm sieve and retaining on 1-
mm sieve. Samples were prepared by adding 10, 20, 30, 40,
and 50%sand by weight, respectively. Standard Proctor tests
were carried out for each mixture to determine the optimum
moisture content and maximum dry densities of the samples.
Shear strength and consolidation tests were performed on five
different mixtures that were prepared at their optimum moisture
content andmaximumdry densities.Tests results showed
that the amount of sand content has a significant effect on
compaction, shear strength, and compressibility parameters
of fibrous peat.

In past few years, the use of bacterial calcium carbonate precipitation (biocementation) has
become popular as a ground improvement technique for sandy soil. However, this technique was not applied
to organic soil. This study focused on bacterial calcium carbonate precipitation and its effect on permeability
in organic soil. A special injection system was prepared for inducing bacterial solution to the samples. The
bacterial solution supplied to the samples by gravity for 4 days in specific molds designed for this work.
Calcite precipitation was observed by monitoring pH value and measuring amount of calcium carbonate.
Change in the permeability was measured before and after biocementation. The test results showed that the
pH values indicates that the treatment medium is appropriate for calcite precipitation, and amount of
precipitated calcium carbonate in organic soil increased about 20% from untreated one. It was also found
that the biocementation can be considered as an effective method for reducing permeability of organic soil.
The results were supported by Scanning electron microscopy (SEM) analysis and energy-dispersive x-ray
(EDX) analysis.

This article presents the result of laboratory study conducted on expansive soil specimens
treated with lignin, rice husk powder (RHP) and rice husk ash (RHA). The amount of lignin produced from
paper industry and RHP were varied from 0 to 20% and RHA from 0 to 10% by weight. The treated
specimens were subjected to unconfined compressive strength (UCS),swelling test and Atterberg limit tests.
The effect of additives on UCS and atterberg limit test results were reported. It was observed that the
additives and curing duration had a significant effect on the strength value of treated specimens. Generally
(except the sample treated with 20% RHP for 3-day) with increasing additive and curing duration the UCS
value increases. A RHP content of 15% was found to be the optimum with regard to 3-day cure UCS.

The fluidity and rheological properties of the grout mixtures treated with rice husk powder (RHP) were studied. The experimen ts were
done by using different RHP content (%4, %8, %12, %16 and %20 respectively) with cement grouts proportioned with different water
to cement ratio (0.75, 1.00, 1.25 and 1.50). This experiment aims to help contribute to the industry in saving the environmen t, to
encourage the municipality to find solutions regarding the disposal to landfills of waste materials and save the environment, to
provide new knowledge to the contractors and developers on how to improve the grout methods and services by using rice husk, and
to sustain good product performance and meet recycling goals. Observations from the tests performed were conducted in the
laboratory where precise data were gathered and completely attained.

The paper presents the results of series of direct shear tests made on recycled waste expanded polystyrene foams (EPS). Waste EPS were thermally modified in an oven at 130 o C through 15 minutes and crushed into aggregate size before tested. Heat treatment of the EPS increased its density from 15 kg/m 3 to nearly 200 kg/m 3. Shear strength behavior of modified EPS were investigated in loose and dense states under three different normal stresses. The test results showed that shear strength behavior of modified EPS is similar to that of sand. Internal friction angle of modified waste EPS in the dense state is higher than of loose state.

This work presents an investigation of the effect of waste aluminum beverage cans strips on strength and swelling properties of lean clay. Waste beverage cans (WBC) were cut into 5 mm strips and mixed with soil in 2, 4, 6, 8, and 10 % (dry weight of soil) before use. Three standard tests were carried on the prepared samples: compaction, free swelling, and California Bering Ratio (CBR). Test results showed that WBC significantly affected the compaction characteristics, swelling and strength properties of the clay.

This study was carried out with an intention to observe any sign of improvement of clayey soil due to addition of waste soda lime glass powder (WSLGP). Waste soda lime glasses were crushed and sieved through #200 (75 μm) sieve and mixed with clay in 3, 6, 9, and 12% in dry weight of the clay. Strength and consistency test were carried out on mixed samples after curing. The test results indicated that the addition of WSLGP into clay has a significant effect on the strength and consistency properties of the clay.

Peat is found in many countries throughout the world where it can be generally seen in thick layers in limited areas. Peat is an extreme form of soft soil and is considered problematic due to the low shear strength and large compressibility. This project presents laboratory finding on the compressibility and shear strength characteristics of fibrous peat with sand column. The peat used in the study is classified as fibrous peat and H 1 –H 4 in Von Post scale. Its liquid limit is 119%. In all tests, the peat used for the tests passing 2 mm and remain on .15 mm. The rounded sand used for making sand column is poorly graded passing from 2 mm sieve size and retaining on 1 mm sieve size. The tests conducted to investigate effect of area ratio of sand column on shear strength and compressibility of the peat. Three different area ratios were used for both compressibility and shear strength tests. Consolidation test results showed that when the area ratio increases compressibility characteristic of the peat improved. Shear strength of the organic soil was also affected from the sand column.

This study concluded the results of a research on the features of cement based permeation grout, based on some important grout parameters, such as the rheological properties (yield stress and viscosity), coefficient of permeability to grout (kG) and the inject ability of cement grout (N and Nc assessment), which govern the performance of cement based permeation grouting in porous media. Due to the limited knowledge of these important grout parameters and other influencing factors (filtration pressure, rate and time of injection and the grout volume) used in the field work, the application of cement based permeation grouting is still largely a trial and error process in the current practice, especially in the local construction industry. It is seen possible to use simple formulas in order to select the injection parameters and to evaluate their inter-relationship, as well as to optimize injection spacing and times with respect to injection source dimensions and in-situ permeability. The validity of spherical and cylindrical flow model was not verified by any past research works covered in the literature review. Therefore, a theoretical investigation including grout flow models and significant grout parameters for the design of permeation grouting was conducted in this study. This two grout flow models were applied for three grout mixes prepared for w/c=0.75, w/c=1.00 and w/c=1.25 in this study. The relations between injection times, radius, pump pressure and flow rate for both flow models were investigated and the results were presented. Furthermore, in order to investigate these two flow model, some rheological properties of the grout mixes, particle size distribution of the cement used in this study and some geotechnical properties of the sand used in this work were defined and presented.