Progress 08/15/16 to 04/14/17
Outputs
Target Audience:This proposal will be interested in the areas of nanophase chemistry, cement chemistry civil engineers and structural engineeers.. Changes/Problems:We want extension for Phase I study till 2018. WORK PLAN FOR EXTENSION PERIOD Evaluating the Use of Modified Biosilica from Biosilica as a Super Pozzolan in Ultra-High Strength Concrete Mixtures Investigator: Dr. Rajan K. Vempati President ChK Group, Inc. 2045 Belgium Dr. Plano TX 75025 chkgroup@att.net (214) 704 4128 Prasad Rangaraju, Ph.D., P.E., FAC Professor 220 Lowry Hall Department of Civil Engineering Clemson University Clemson, SC, 29634-0911 (864) 656-1241 864) 656-2670 prangar@clemson.edu ChK Group, Inc. We will make 10 lbs. of Biosilica using Harrop Industries, Inc. rotary furnace. Then we will synthesize Modified Biosilica (MB) using HCl to use as ultra high performance (UHPC) concrete. Clemson University INTRODUCTION The proposed program covers the work plan to be accomplished in the extension period requested to complete the USDA SBIR study. During this extension, the characteristics of Modified Biosilica (MB) finalized from the preliminary treatments with varying composition and concentrations of HCl will be studied. The properties of the MB to be assessed include: Density Particle size distribution Specific surface area X-ray diffraction pattern to assess the glassy nature of the silica and pozzolanic reactivity Strength activity index with portland cement Time of Setting (Initial and Final) Flow Unit weight Rate and Degree of hydration, and Microstructure and composition of Modified Biosilica and the reaction products obtained from the pozzolanic reactions Density Due to its level of purity, the density of the MS can be expected to be significantly lower than that of portland cement. If not properly accounted for, the use of MS on a simple mass replacement of portland cement can result in a grossly erroneous prediction on the performance of the UHPC mixtures. In this regard, the density of the MS will be determined using a LeChatelier's Flask using kerosene as a displacing liquid as per the ASTM C 188 standard. Particle Size Distribution The particle size distribution of a pozzolanic material plays an important role not only in affecting its pozzolanic reactivity but also its ability to act as a filler-material in the interfacial transition zone in the portland cement concrete. The particle size distribution of the MS will be determined using X-ray sedigraph. Also, in this regard the dispersion of MS in the cement paste is of utmost importance for its effective use. Methods to evaluate dispersion of MS in cement paste will be developed as part of this study. Specific Surface Area The specific surface area of a pozzolanic material is another fundamental physical parameter that dictates the reactivity of a material such as MS. The specific surface area of the MS sample will be evaluated using the BET method. X-Ray Diffraction X-ray diffraction patterns will be used not only to characterize the composition of the MS but also to monitor the changes in the hydration products that form upon pozzolanic reaction with lime and portland cement. Strength Activity Index with Portland Cement The strength activity index of the MS sample will be evaluated using the procedure described in the ASTM C 311 standard. In order to determine the optimal replacement level for achieving maximum strength, a range of cement replacement levels will be evaluated. The strength activity index will be determined both at 7 days and 28 days of age. Time of Setting (Initial and Final): Time of initial and final setting are important parameters of portland and blended cements which determines the age at which the mixture attains sufficient rigidity to take a final shape and some bearing stresses to enable further operations. Time of setting will be determined using a Vicat Apparatus as per the ASTM C 191. Flow: Flow of mortar is a fundamental rheological measure of a cementitious mixture. It is important to know how MS influences the flow behavior of mortars as a function of its dosage in the mixture. Flow of the MS mortars will be determined using ASTM C 1437-01. Unit Weight: Unit weight of the mortars will be determined and compared to the theoretical values to gravimetrically assess the air content of the mixes. Any tendency of MS to entrain air in the mixture will be ascertained from these findings. Rate and Degree of Hydration The degree of hydration represents the amount of portland cement that has hydrated at any given time. Periodic determination of degree of hydration provides information on the rate of hydration of a given cement. Information on the rate and degree of hydration provides important information on the accelerating effects of MS on the hydration of cement and the effectiveness of pozzolanic reaction. The degree of hydration is determined by measuring the amount of non-evaporable water present in the cement. This is accomplished by taking a known mass of hydrated cement paste and conditioning it to a constant mass at 105ºC and thereafter heating it to over 1000ºC in a muffle furnace to determine the chemically bound water in the hydrated cement paste. The amount of mass loss primarily attributable to moisture loss can then back-correlated to determine the degree of hydration in the portland cement. Microstructure and Composition of the Pozzolanic Reaction Products It is important to characterize the microstructure of the MS and that of the hydrated cement paste containing the MS sample to understand the specific role MS will play in improving the properties of the hydrated cement paste and hence concrete. This will be accomplished by using secondary and back-scatter detectors in a Hitachi S-3400N Scanning Electron Microscopy equipped with an Oxford X-ray analysis unit. Powder mounts as well as epoxy-impregnated specimens will be evaluated to assess the microstructure and the composition of the hydration products. Testing Matrix Table 1 - Matrix of Tests Test Relevant Standard Number of Samples Density ASTM C 188 3 Particle Size Distribution --- 2 Specific Surface Area (BET, X-Ray Sedigraph) --- 2 Strength Activity Index ASTM C 311 3 Time of Set ASTM C 191 3 Flow ASTM C 1437 2 Unit Weight ASTM C 138 3 Rate and Degree of Hydration --- 2 XRD/XRF --- 1 SEM-EDX of Pastes and Mortars --- 1 Final Report: At the conclusion of the study a comprehensive final report will be prepared and submitted. Interim progress on the work will be updated through phone calls and emails. Amount of Sample Needed We will require 10 lbs of the MS sample to conduct all the testing proposed. Budget No additional budget is requested for the extension period requested. What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?We are calcinating organic compounds from roie hulls to make12 lbs of Biosilica (off-white/white and amorphous SiO2) by using rotary furnace;then, synthesize modified Biosilica. Then test Nanophase Silica to be an additive for ultra high performance concrete (UHPC). We are seeking extension for Phase I project.
Impacts
What was accomplished under these goals?
In Mid Term report: We tested Nanophase Silica (NS) from rice hulls which is easy to synthesize and compete with silica fumes. We test the NS as an ultra high performance cement (UHPC).
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Progress 08/15/16 to 04/14/17
Outputs
Target Audience:The Target Audience is: cement manufacturers, Cement additive industries, high performance concrete for bridges, high risen building and pavements, architectural, transportation,green chemists,building and cement professionals.. Changes/Problems:We were able to make Nanophase Silica, in range of 60 -100 nm, using a special grinder made by NETZSCH, Germany company. The process does not use of inorganic or organic compounds. Also,steam can be generated by incinerating rice hulls that can be used for grind. In Phase II proposal we will make 30 lbs. and test the product as Ultra High Performance Concrete IUHPC). What opportunities for training and professional development has the project provided?
Nothing Reported
How have the results been disseminated to communities of interest?The Biosilica andf Modified Biosilica can be used for high value added products instead landfilling. The raw material can fetch the producers. What do you plan to do during the next reporting period to accomplish the goals?This is the final report and Phase II will be submitted in future.
Impacts
What was accomplished under these goals?
Followings were accomplished: Made Biosilica from rice hulls Synthesized Modified Biosilica (MB)using acid Grind Biosilica particles in average100 nm. Calculated the steam generated by incinerationg 50,000 tons ofrice hulls Successful Tested MB for Ultra High Performance Concrete (UHPC)
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