The effect of concrete additives on physical properties of soil stabilized with lime

Sand and gravel materials are commonly use for structure layers of roads. These materials are providing from riverbeds and mines، which are usually far from the operation site area. While the process involves manipulation of riverbeds and mines it also has a significant cost، most of it in extraction، transportation، Gradation correction، fuel and machinery. Researches done in different countries are showing that in cases soil is in good quality، stabilized mixture of soil can be used instead of sand and gravel. These can reults a signifactnt amount of money saving by providing soil from near the road and eliminating the process of Gradation correction. However، there are resistance and inflammatory parameters of fine soils، which play an important، usually problematic، role in structure buildings. The abundance of fine-grained clayey soils in the country، have created serious problems in construction projects. One of the ways to modify or improve the properties of these soils is stabilizing. Lime as a stabilizer for fine-grained soils is famous. In this thesis، the effect of four chemical additives on the CBR strength of soil stabilized with lime is studied. In addition، effect of additives on properties such as swelling، water absorption and density of soil stabilized with lime is studied. These additives with names «Panplast R»، «RB - PC 386»، «RB - PC 375» and «Planicrete SP» as a lubricant and concrete superplasticizer have the desired effect on the chemical and physical properties of concrete. Moreover، the Cementation act of stabilized soil with lime is like cement. In this study، the effects of those additives on lime-stabilized soil are studied. First four different combinations of soil and different percentages of lime made. The results obtained optimized percentage of lime. Then optimized percentage of lime and different percentages of additives used to build the different samples. In order to avoid faults and testing errors، each combination made by two samples. All desired results were presente as mean values obtained from two samples. Total of 49 samples were built and tested. Due to determine the effect of curing time of each combination، two sample with 7-day curing time and two other with 14-day curing time are made. In order to preserve the moisture in the samples during the curing time they were stored in sealed thick nylon bags. After curing time for each sample for 96 hours at constant temperature water baths were maintaine to monitor inflation and the water absorption. After time the CBR test done. Finally، the Additives «Panplast-R» and «RB-PC 375» had a favorable impact on listed properties، so that the CBR result was 90% and 99%، the «RB-PC 386» was almost effectless، and the «Planicrete-SP» has shown Negative impact on the properties of interest. so that the CBR result was 65%.