Linseed Oil Formulations As Curing And Antiscaling Compounds For Concrete

LINSEED OIL FORMULATIONS AS CURINGAND ANTISCALING COMPOUNDS FOR CONCRETECecil H. Best and James F. Crary, College of Engineering,Kansas State University; andLyle E. Gast and William L. Kubie , Oilseed Crops Laboratory,U. S. Department of Agriculture, PeoriaAn extensive testing program was undertaken to determine the effectivenessof linseed oil in mineral spirits both as a curing compound and as an antiscaling compound for inadequately air-entrained portland cement concrete.The testing program is discussed in light of the immediate and residualeffectiveness and the value of such linseed oil formulation treatments. LABORATORY tests were conducted to determine the effectiveness of linseed oil in amineral spirits solution as a curing and antiscaling compound for concrete. A discussion of the test materials, facilities and equipment, procedures, and results follows.MATERIALSConcreteA single lot of Type I portland cement (ASTM C 150) was used. The entire supply ofcement was blended into steel drums that were then sealed with gasketed lids to protectthe cement from atmospheric water and carbon dioxide until time of use.The coarse aggregate used was crushed limestone from a quarry in WaubunseeCounty, Kansas. It was graded within t he limits for No. 67 in ASTM C 33 (sieve size:%in. to No. 4). Its mea sured absorption capacity was 1.38 pe rcent of oven-dry weight.The fine aggregate used was from a deposit in the Kansas River. This material isproduced according to the specifications for state road and bridge construction (sectionJl-3) of the Kansas State Highway Commission.Supplies of coarse and fine aggregates w, re individually tempered to the saturated,surface-dry condition and stored in 30-gal (114 litre) steel drums with gasketed lids.This was done to preserve the moisture condition until time of use when a given drumwas emptied and the contents were thoroughly blended prior to batching to redistributeany possible moisture concentration that may have occurr ed during storage.The air-entraining agent was a commercial neut ralized vinsol resin (ASTM C 494).Tap water was used for mixing.Curing and AntiscalingBoiled linseed oil, mineral spirits, and resin-based and wax-based white-pigmentedcuring compounds (ASTM C 309) were obtained from a commercial supplier in lots sufficient for the entire project.Boiled linseed oil emulsion developed by the Northern Laboratory was obtained froma commercial producer.All other curing and antiscaling materials, including the National Flaxseed watersoluble curing compound, were supplied in quantity by the Northern Laboratory.Publication of this paper sponsored by Committee on Curing of Concrete.63

64FACILITIES AND EQUIPMENTAll work was carried out in the De partment of Applied Mechanics laboratories, whichhouse a full complement of standard concrete fabrication and testing equipment.The surface abrasion apparatus was built according to drawings and instructions fromthe California Highway Commission. We followed the California testing procedure andcall the results California abrasion loss, which may be interpreted as a relative measure of surface strength.PROCEDURESStandardsApplicable portions of current ASTM specifications for concrete testing were adheredto throughout the project with the following exceptions:Our old automatic freeze-thaw equipment conforms with the requirements of ASTMC 666 except for the requirement that a nominal cycle shall not exceed 4 hours. With afull load of 50 specimens in brine in individual polyethylene containers, the nominal cycle in our machine is 6 hours. Photography was used instead of weight loss and durability factor to record performance.Abrasion resistance was determined by the California method rather than by ASTMC418.Concrete Mix ProportionsA single concrete mixture was proportioned by trial to yield a standard compressivestrength of 4,000 to 5,000 psi (27.58 to 34.47 MPa) and 5 to 6 percent entrained air (byvolume). (The prescribed amount of entrained air is inadequate because it is less thanthe average or 7 percent 1·ecommended by ACI for concrete containing %-in. maximumaggregat e .) Properties of the 1·esulting concrete we1·e slump, 3% in. (8.9 cm)· unitweight, 140.1 lb/ft 3 (2244 kg/m 3); air content, 5.5 percent (by volume): water/cementratio, 6.2 gal/sack (0 .55) ; cement fact or, 5. 1 s acks/yd 3 (284 kg/m3); and standard compressive strength, 4,530 psi (3123 kPa). Mixture proportioning was not an element ofthe study, therefore mix-determined proportions were used for making all test specimens.Test SpecimensFor each test condition (Table 4), two slabs 16 by 18 by 4 in. (40.6 by 45.7 by 10.2cm) and three beams 3 by 4 by 16 in. (7.6 by 10.2 by 40.6 cm) were cast from a singleconcrete batch.At the conclusion of the prescribed curing and surface treatment, three beams weresawed from one of the slabs, vacuum saturated, and tested in flexure with center-pointloading (three values) and in modified-cube compression (six values).The remaining slab was stored in the laboratory and air controlled at 70 F (21 C)and 50 percent relative humidity pending abrasion testing at 2, 4, and 6 months.The formed faces of the three beams were coated with boiled linseed oil in mineralspirits to inhibit salt intrusion through these faces; the finished surface of each specimen was the only surface of interest. AU beams were exposed to laboratory air at70 F (21 C) and 50 percent relative humidity for a period of 14 days before being exposedto freezing and thawing in 2 percent sodium chloride solution.Portions of beam ends from the flexure and modified-cube compression tests weretxeated.on.the.i:tacture.sw;Iace-wit O-pe-l'Gent.s ulfur-ic;:- ae.id-solut-ion-and-wei·e-e-ha-rredin an oven to delineate penetration of the prescribed surface treatment material into theconcrete substrate.RESULTSData for strength in flexure and in modified-cube compression are given in Table 1,and California abrasion loss data for all conditions of test are given in Table 2. Typical durability results through 300 cycles of freezing and thawing in 2 percent NaCl brine

Table 1. Compressive andflexural strength data.Compressive StrengthFlexural Stre ngthV(percent)Strength(psi)0(psi)V(percent)Stren 904,6904,860290211211110735.754.1 84.222 .351. 1781131.972.496. 32493145334;666.995.725. 734.25(psi)Note: 1 psi 6 894 757 kPa.Table 2. California abrasionloss data.California Abrasion Loss (grams)Condition2 Months4 Months6 Months1100120013001400150029.526.329.820.223.929. 726.529 .032. 9.426.627 .223.023.126.423. 727.225.04006400740084009401032.127.028.327 401240134014401524.226.022.831.233. Depth of Penetrationof Surface TreatmentFormulation (mm)ConditionDepth of Penetrationof Surface TreatmentFormulation (mm)11001200130014001500n/a240044005'I, to 1 'I,210222012202230123021 to 2Not measurable2Not measurable5400140024003 1/,Table 3. Penetration data.'!,1 to 21/, to 1 '/, 1/,40064007400840094010401140124013401440151/,to 1 '/, '/, 'I, '!,1/, Lu 11/, to 1'I,1 to 21/, to 1

66are shown in Figure 1, and data from penetration of surface treatments into the concretesubstrate are given in Table 3.DISCUSSION OF RESULTSThis test was designed to answer certain questions about inadequately air-entrainedportland cement concrete. Testing was done within the constraints of particular conditions (Table 4).Question 1Is boiled linseed oil in mineral spirits an effective antiscaling compound for concreteexposed to freezing and thawing in the presence of deicing salts?Test conditions 1100 through 1500 (F ig. 1) are used to answer this question. Condition 1100 (cont rol) shows evidence of surface scaling after only 20 cycles, with serioussurface det erioration s etting in after about 40 cycles. Conditions 1300 and 1500 held upbetter than the cont rol through 20 cycles but performed much like the control thereafter.Condition 1200 held up well t hrough about 80 ycles, and condition 1400 through morethan 100 cycles . The r efore, 1400 (75 percent linseed oil in mine r al spir its) is superiorto 1200 (50 percent linseed oil in mineral s pirits), which i s superior to 1300 (25 percentlinseed oil in mineral spirits), which is roughly equal to 1100 (control) in inhibitingsurface deterioration under the prescribed test conditions. Recoating condition 1300 atthe same coating rate after 24 hours (producing condition 1500) did not improve performance significantly.Within these test constraints, boiled linseed oil in mineral spirits is an effectiveantiscaling agent roughly in proportion to the concentration of oil and therefore in proportion to the oil treatment rate for a one-shot treatment. A one-shot treatment ismarkedly superior to a two-shot treatment, which totals the same oil treatment rate.Question 2Is the effectiveness of boiled linseed oil in mineral spirits as an antiscaling compoundimpaired by the presence of a wax-based or a resin-based curing compound?Pertinent test conditions for answering this question are 2201 through 2302.The performances of conditions 2201 (wax-cured) and 2301 (resin-cured) were verysimilar to that of condition 1100 (control), whereas the pe rformance of condition 2202(wax-cured plus t reat ment with linseed oil in mineral spirit s ) and 2302 (resin-cured plustreatment with linseed oil in mineral spirits) was very s imilar t o that of 1200 (standardcured plus treatment with linseed oil in mineral spirits), with perhaps a slight edge tocondition 2202.Table 3 gives the depth of peneh·ation of oil through the curmg membranes to a depthequal to or greater t han t he penetration depth in the absence of curing membranes.Figure 2a s hows the r esin- cured specimen, and Figure 2b shows an oil-treated, resincured specimen before sulfuric acid treatment. The light streak at as much as 5 mmbelow the treated surface is pigment from the curing compound carried into the concretesubstrate by the boiled !IP.seed oil in mineral spirits.Within these test conditions the presence of a wax-based or a resm-based curingcompound does not impair the effectiveness of boiled linseed oil in mineral spirits as anantiscaling compound.Question 3any-0f-seve-r.a-l-athe-r :ins eea-0il---fo1 mulat-ions--effective-a nttsca-tlng-compounds ?Test conditions 2102, 4001 to 4003, 4007 to 4010, and 4013 are used to answer thisquestion.The performance of blends of ZS-bodied linseed oil and boiled linseed oil emulsion(4001 to 4003) was roughly equivalent to the performance of boiled linseed oil in minerals pirit s (1200) through 100 cycles of freezing and t hawing. Condition 4001 (15 percentZ8 and 85 percent emuls ion) was 1·oughly equal t o 4002 (20 percent Z8 and 80 percentemulsion) , which was superior to 4003 (2 5 percent Z8 and 75 percent emuls ion) , which- - - - -. i: