Ali Asghar Firoozi

Laboratory investigation on the strength characteristics of cement treated base

Cement-Treated Base (CTB) is a non-conventional method used in road bases materials to improve its engineering properties due to the hardening of cement when moisture is present and extends the period of curing times. This study investigates the effects of cement additive on properties of base layer using laboratory mechanistic evaluation of stabilized soil mixtures. Laboratory tests conducted were Unconfined Compressive Strength (UCS), Indirect Tension test for Resilient Modulus (ITRM) and Flexure Strength (FS) tests. The results revealed that by adding Portland cement, the mechanical properties of the mixture have improved where the UCS is found to be an important quality indicator. In addition, the variables that influenced these tests, which are cement content, curing time, moisture content, and dry density, play important role to determine the performance of CTB. This paper presents the finding of a correlation conducted to analyse the influences of these variables using regression and ANOVA to establish significant models with the aim of predicting the strength base on mixture parameters. Keywords: Cement-Treated Base, Unconfined Compressive Strength, Indirect Tension test for Resilient Modulus, Flexure Strength, Moisture Content, Dry Density, Regression Analysis.

Effects on engineering properties of cement-treated road base with slow setting bitumen emulsion

Abstract This study investigated the effects of the type and amount of Portland cement and cationic slow setting bitumen emulsion additives on the short- and long-term performance of road-based properties using laboratory mechanistic evaluation. Stabilised specimens with Portland cement (0–6%) and bitumen emulsion (0–6%) were compacted, cured for 7, 28 and 60 days; and finally subjected to different stress sequences to study their unconfined compressive strength, indirect tensile resident modulus and indirect tensile strength tests. The durability of stabilised soil specimens was investigated by conducting wetting and drying (WD) cycling test on 7 days cured specimens. The results showed the added 4% portland cement–3% bitumen emulsion mix was ideal and produced a 179.4% reduction in the water absorption and permeability, 256.3% reduction in volume changes and 211.95% reduction in weight losses relative to a 4% cement sample. This paper presents the findings of a correlation that was conducted using non-linear regression analysis regarding the influences of the affected variables in order to establish models to predict the mixture strength parameters.

Fundamentals of soil stabilization

Clayey soils are usually stiff when they are dry and give up their stiffness as they become saturated. Soft clays are associated with low compressive strength and excessive settlement. This reduction in strength due to moisture leads to severe damages to buildings and foundations. The soil behavior can be a challenge to the designer build infrastructure plans to on clay deposits. The damage due to the expansive soils every year is expected to be

Examination of the behavior of gravity quay wall against liquefaction under the effect of wall width and soil improvement.

1 billion in the USA, £150 million in the UK, and many billions of pounds worldwide. The damages associated with expansive soils are not because of the lack of inadequate engineering solutions but to the failure to identify the existence and magnitude of expansion of these soils in the early stage of project planning. One of the methods for soil improvement is that the problematic soil is replaced by suitable soil. The high cost involved in this method has led researchers to identify alternative methods, and soil stabilization with different additives is one of those methods. Recently, modern scientific techniques of soil stabilization are on offer for this purpose. Stabilized soil is a composite material that is obtained from the combination and optimization of properties of constituent materials. Adding cementing agents such as lime, cement and industrial byproducts like fly ash and slag, with soil results in improved geotechnical properties. However, during the past few decades, a number of cases have been reported where sulfate-rich soils stabilized by cement or lime underwent a significant amount of heave leading to pavement failure. This research paper addressed the some fundamental and success soil improvement that used in civil engineering field.

Effect of styrene-butadiene copolymer latex on properties and durability of road base stabilized with Portland cement additive

Deformation of quay walls is one of the main sources of damage to port facility while liquefaction of backfill and base soil of the wall are the main reasons for failures of quay walls. During earthquakes, the most susceptible materials for liquefaction in seashore regions are loose saturated sand. In this study, effects of enhancing the wall width and the soil improvement on the behavior of gravity quay walls are examined in order to obtain the optimum improved region. The FLAC 2D software was used for analyzing and modeling progressed models of soil and loading under difference conditions. Also, the behavior of liquefiable soil is simulated by the use of “Finn” constitutive model in the analysis models. The “Finn” constitutive model is especially created to determine liquefaction phenomena and excess pore pressure generation.