Browsing by Author "Sezer, Alper"
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Item Assessment of the effect of sulfate attack on cement stabilized montmorillonite(Techno-Press, 2016-03-07) Kalıpçılar, İrem; Sezer, Gözde İnan; Altun, Selim; Sezer, Alper; Mardani, Ali Aghabaglou; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0003-0326-5015; AAJ-6415-2021; 57669486700In this study, aiming to investigate the effects of sulfate attack on cement stabilized highly plastic clay; an experimental study was carried out considering the effects of cement type, sulfate type and its concentration, cement content and curing period. Unconfined compressive strength and chloride-ion penetration tests were performed to obtain strength and permeability characteristics of specimens cured under different conditions. Test results were evaluated along with microstructural investigations including SEM and EDS analyses. Results revealed that use of sulfate resistance cement instead of normal portland cement is more plausible for soils under the threat of sulfate attack. Besides, it was verified that sulfate concentration is responsible for strength loss and permeability increase in cement stabilized montmorillonite. Finally, empirical equations were proposed to estimate the unconfined compressive strength of cement stabilized montmorillonite, which was exposed to sulfate attack for 28 days.Item An investigation into strength and permittivity of compacted sand-clay mixtures by partial replacement of water with lignosulfonate(Polish Acad Sciences Inst Physics, 2016-07) Sezer, Alper; Boz, Aslı; Tanrinian, Nazar; Mardani, Ali Aghabağlou; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0003-0326-5015; AAJ-6415-2021; 57669486700Strength and permeability of sand-bentonite mixtures are of main concern, particularly in liner design. This study presents the results obtained from an experimental investigation of strength and permittivity of compacted sand-bentonite mixtures in the presence of water-reducing admixture of lignosulfonate. For this, sand-bentonite mixtures containing 4, 8, 12, 16% of bentonite were subjected to standard Proctor tests, to obtain the optimum water content and maximum void ratio of the mixtures. Similar specimens were prepared by partially replacing 0.5, 1 and 2% of water in the mixture with lignosulfonate. Additional specimens containing 16% of bentonite were prepared with 5% deviation towards the wet and dry sides of optimum water content, which was partially replaced with lignosulfonate for evaluation of the effects of deviation from optimum moisture content during densification. It was observed that partial replacement of water with lignosulfonate slightly increases the strength and decreases the permittivity, and that this effect was more pronounced as the replacement level was increased. Additionally, test results reveal that lignosulfonate replacement was more effective on the dry side of optimum water content.Publication Prediction of mechanical and penetrability properties of cement-stabilized clay exposed to sulfate attack by use of soft computing methods(Springer, 2020-05-06) Sezer, Alper; Sezer, Gözde Inan; Mardani-Aghabaglou, Ali; Altun, Selim; Mardani-Aghabaglou, Ali; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0003-0326-5015; C-7860-2015; AAJ-6415-2021Similar to its effects on any type of cementitious composite, it is a well-known fact that sulfate attack has also a negative influence on engineering behavior of cement-stabilized soils. However, the level of degradation in engineering properties of the cement-stabilized soils still needs more scientific attention. In the light of this, a database including a total of 260 unconfined compression and chloride ion penetration tests on cement-stabilized kaolin specimens exposed to sulfate attack was constituted. The data include information about cement type (sulfate resistant-SR; normal portland (N) and pozzolanic-P), and its content (0, 5, 10 and 15%), sulfate type (sodium or magnesium sulfate) as well as its concentration (0.3, 0.5, 1%) and curing period (1, 7, 28 and 90 days). Using this database, linear and nonlinear regression analysis (RA), backpropagation neural networks and adaptive neuro-fuzzy inference techniques were employed to question whether these methods are capable of predicting unconfined compressive strength and chloride ion penetration of cement-stabilized clay exposed to sulfate attack. The results revealed that these methods have a great potential in modeling the strength and penetrability properties of cement-stabilized clays exposed to sulfate attack. While the performance of regression method is at an acceptable level, results show that adaptive neuro-fuzzy inference systems and backpropagation neural networks are superior in modeling.Item Sustainability of cement-stabilised clay: Sulfate resistance(Ice Puplishing, 2018-08) Kalıpçılar, İrem; Sezer, Alper; Altun, Selim; Sezer, Gözde İnan; Mardani, Ali Aghabaglou; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0003-0326-5015; AAJ-6415-2021; 57669486700Sulfate attack on cement-stabilised soil is a durability problem which is directly related to the sustainability of the foundations. In this study, an experimental framework was established to evaluate the effects of sulfate attack on the strength and penetrability properties of cement-stabilised kaolin clay. Specimens incorporating ordinary Portland, pozzolanic and sulfate-resistant cements were compacted by standard Proctor effort, later cured for 1, 7, 28 and 90 d. Sodium and magnesium sulfates were used at concentrations of 0.3, 0.5 and 1%. At the end of the curing periods, the strength and penetrability characteristics of specimens were determined by conducting unconfined compressive strength and chloride-ion penetration tests. The results revealed that increase in cement content and curing time led to evident increase in strength and decrease in penetrability. Moreover, magnesium sulfate salt adversely affected hydration bonding between soil and cement in stabilised specimens. Increase in cement content caused increases in unconfined compressive strength; however, the rate of strength gain decreased in specimens exposed to sulfate attack. After 7 d of curing, the penetrability of specimens incorporating normal Portland cement is lower compared with that of other specimens including other types of cements; nevertheless, the reverse situation is valid after 28-d curing.