Sand Dunes Stabilization Using Silica Gel and Cement kiln Dust
Sand Dunes Stabilization Using Silica Gel and Cement kiln Dust
College of Engineering / University of Anbar
https://nahje.com/index.php/main/article/view/176
This research includes the study of adding some available cheap and Local materials to Sand Dunes (SD) such as, Silica Gel (SG) and Cement kiln Dust (CKD) which are used as stabilizers and sand improvement . The Laboratory tests out on (June 2013 to November 2013 .) Some Physical and chemical characteristics of(SD),(SG) and (CKD) were obtained, also Grain Size Distribution(GSD) and chemical composition were obtained. The program was divided into two stages the first one includes preparing four mixtures three of them Silica gel were added to tape water to make solution (2.5%,5% and 7.5%) , then adding to the sand dunes, which is denoted by (m1, m2 and m3) respectively , the fourth mixture represent reference( sand dunes) ,these mixtures aging for (7, 14 and 28 ) days. Pure sand dunes and these three mixtures were tested to determine the wind velocity effects on drifting sand, shear strength force, cohesion and penetration .The second stage includes determining the best results of three previous mixtures, which called typical mixture, and (2.5%,5% and 7.5%) of CKD were added to the typical mixture, which is denoted by (m41, m42 and m43) respectively , these mixtures aging- curing period- for (7, 14 and 28 ) days.
Generally, this study showed significant improvement in the performance of sand dunes by using Silica Gel and Cement Kiln Dust, which means that, they can be used as stabilizer and soil improvement as economic and available materials.
NUCEJ Vol.18 No.2,2015 Rammal,Jubair, pp.179-1911866-solution will mixed with CKD then spry to the sand dunes molds , this Mixture denoted by the symbol (m4). 7-Determine the engineering characteristics of mixtures , sand drifting, , drained shear strength-resistance-parameters (c ,ø),which determined by the direct shear test to obtain the shear strength-resistance at failure (τf) and penetration after (7, 14 and 28) days for the mixture(m4).8-Determine theoptimum mixture (bestresult) of engineering characteristics for mixtures , figure (6) shows flow chart of methodology .Figure 6:Flowchart of methodology10Results and DiscussionThis research includes stabilization of sand dunes using silica gel and (CKD) ,sand dunes grain size distribution . Table (2) shows some chemical and physical properties of silica sand, Thespecific gravity is (2.56). The chlorides and sulfate were obtained according to the specification(BS1377 test No.9) are (0.011% and 0.11% ) respectively .The hydrogen ion concentration (pH-value ) is (7.85) , also the coefficient of uniform (CU) is 3.6, Figure.(4), shows that the sand dunes is classify as sandy (97.09% sand and 2.91% clay) .Table (3) shows the chemical analysis of silicagel represent one of the dissolved polymers. The polymer silicate ions consist of manychain series or three-dimensional chain .The chemical formula of silicagel is (Na2O. SiO3.5H2O). Figure.(5) show the grain size distribution of CKD , which show that (75% ) is smaller than (10 microns) , and the bulk density about ( 800 -850) (gram/litter) and the hydrogen ion concentration (pH-value ) is between (10.5 -13) .Table (5) show the Wind effect or drifting sand velocity , Four velocities (5, 15, 30 and 45 ) meter per second by using blower motor to apply air (wind) on the sand dunes surfaces to detect the initial velocity which can effect on the sand surfaces, and Anemometer apparatus used to measure air velocity .The results show that the drifting sand happen at ( 5 m/s) for pure sand dune, ( 30 m/s) required to drifting sand occur for (m1) at (7 days age) and ( 45 m/s) required to drifting sand occur for (m1) at (all ages), while drifting sand not occur for (m1) at (28 days age). drifting sand not occur for (m2) at (all ages). drifting sand not occur for (m3) until velocity(45 m/s) for (all ages).The results show that adding silica gel is increasing sand resistance to drift (erosion), and the best result is adding (5%) of silica gel to sand dunes , which denoted by mixture (m2).