Mechanical characteristics of soft clay treated with fibre and cement
ABSTRACT: In this study, the influence of three types of fibre – polypropylene, recycled carpet and steel – on the mechanical properties of cement-treated clay is investigated. Cement-treated clay specimens were prepared with cement contents of 5%, 10% and 15% by weight of dry soil, and cured for 14 days. To investigate and understand the influence of different fibre types and contents, three different percentages of fibre content were adopted. The results of unconfined compression tests on 90 cylindrical samples of cement-treated clay with varied cement and fibre contents are analysed to discern the relationships between these parameters and the key mechanical properties, including unconfined compressive strength and stiffness of treated soil. Furthermore, indirect tension test results of a further 90 treated soil samples have been used to determine the influence of fibre and cement content on the tensile strength of the treated soil. The fibre reinforcement increases the peak compressive strength. The a...
ENHANCING THE ENGINEERING PROPERTIES OF EXPANSIVE SOIL USING BAGASSE ASH AND HYDRATED LIME
The main objective of this paper is to investigate the influence of hydrated lime and bagasse ash on engineering properties of expansive soil obtained from an array of laboratory tests. Bagasse ash is a readily available waste by-product of the sugar-cane refining industry posing risks to environment. Bagasse ash is considered in this investigation in order to evaluate the potential benefits of its pozzolanic material for stabilisation of expansive soil. The preparation of stabilised soil specimens was conducted by changing the bagasse ash contents from 0 to 25% by dry weight of expansive soil along with an increase in hydrated lime. The bearing capacity and shrinkage properties of stabilised expansive soil were examined through a series of experimental tests including linear shrinkage and California bearing ratio (CBR) after various curing periods of 3, 7 and 28 days. The results reveal that the additions of hydrated lime and bagasse ash improved the strength and bearing capacity of stabilised expansive soil remarkably, and meanwhile significantly reduced the linear shrinkage of treated expansive soil. Hence, the application of hydrated lime and bagasse ash as reinforcing material can not only enhance the engineering properties of expansive soil, but also facilitate sustainable development by using sugarcane waste by-product to improve unusable clay material in road construction.
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.