Sugarcane ash: Compressive strength and rheology of a self-compacting concrete

Abstract

In the present research work, the mechanical and rheological properties of a self-compacting concrete (CAC) were determined, with additions of sugar cane ash (CCA) as a pozzolanic material; plus, a superplasticizer additive to maintain workability. The mechanical properties were determined as a function of curing time. The CCA was collectedfrom the cane fields during the harvest in the province of Ascope (Trujillo-Peru) after burning them, then it went through a grinding processusing only the Nº325 mesh pass-through in this case; the Portlandcement (PC) used was the type I; the fine aggregates (coarse sand) and coarse aggregate were acquired from the quarries of El Milagro (Trujillo-Peru). The superplasticizer addit ive used was Euco Plastol 3000PC. The mix design was based on the recommendations stipulated in ACI-211, the percentages of CCA additions were (0.5, 1.0, 1.5 2.0, 2.5, 3.0, and 3.5) %, and the superplasticizer additive was used at (0.69, 0.72 0.77, 0.85, 0.98, 1.18, 1.45 and1.89)% in both cases with respect to the weight of the cement used, the data collection times of mechanical tests (ASTM C39 and ASTM C469) were performed at (7, 14, 28 and 56) days after making the mixtures; In addition, characterization was carried out in the fresh state of the mixture, accordingto the ASTM C1611 andASTM C1621 standards and theEFNARC (2002) and GPE (2005) specifications in order to evaluate their fluidity, the CCA was characterized by AT D, ATG, and RDX. The aggregates were characterized by the standards ASTM C136, ASTM C566, ASTM C29, ASTMC127, andASTM C128. From the results obtained, we can mention that the addition of CCA exceeds the limit of the recommendedwater/finesratio, although it has shown to improve the effectiveness of self-compacting concrete, partially; the evaluation of the fillingcapacity determined that the sampleswith the addition of CCA (0.5, 1.0, 1.5 and2.0)% are classSF2, while the sampleswith the additionof (2.5, and3.5)% belongto the SF3 class; the passability analysis according to ASTM 1621 classified the samples with pozzolanaddition of (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0)% as mixtures with novisible blocking, however for the sample with 3.5% of additionpresents an apparent blockage, with respect to fluidity all samples were classified as VS2 type, however the samples with addition of CCA at 3.0 and 3.5% present a high degree of viscosity; thesuperplasticizer additive is the factor with the greatest influence on the rheological properties of the CAC, the mechanical properties increased as a function of the curing time, among the values obtained are those of 622 kg/cm2, in the case of compressivestrength and a modulus of elasticity of 317.962 kg/cm2, whichare values that exceed the samples without the use of CCA, so these are considered to have pozzolanic properties.