SUGARCANE BAGASSE ASH SAND (SBAS): BRAZILIAN AGROINDUSTRIAL

BY-PRODUCTFOR USE IN MORTAR

Nama Kelompok :1. Yeni Fitriani2. M. Andrey Pradana3. Ariya Giri Chandra W4. Maulina Cita Devi5. Vanessa Vriscilla

Abstract

Mortar pores without SBAS

Mortar pores with SBAS

SBAS

SBAS in corporation30 % , by mass

Cl- depthCl- depth

INTRODUCTION

Sugarcane production is a major agricultural activity in Brazil. Sugarcane bagasse ash sand (SBAS) is one of the major by-products from the processing of sugarcane to produce sugar and ethanol. SBAS has high silica (SiO2) content (above 60% by mass), with variable and coarse particle size distribution.

INTRODUCTION

SBAS is the crude residue generated after the burning of sugarcane bagasse. This residue is collected from boilers at plants and has low levels of pozzolanic reactivity. The reactivity of sugarcane bagasse ash is directly dependent on the conditions when burning the bagasse. Maximum reactivity can be achieved by burning bagasse at around 500 C.

INTRODUCTION

In addition, sugarcane bagasse ash can become reactive by ultrafine grinding. However, grinding and/or controlled burning require energy, and treating large volumes of SBAS using these processes is costly. The SBAS used in this experimental programme had a predominantly crystalline structure of SiO2a-quartz, as determined by X-ray diffractometry in other studies, which revealed the absence of an amorphous halo in the diffractograms.

MATERIALS

Sugarcane bagasse ash sand (SBAS) was used as a fine aggregate in partial substitution for natural sand (at levels of 30% and 50%, by mass) to produce mortar.

BEFOREAFTER

The composition of the mixture (SBAS + natural sand) was classified according to the usable area as a fine aggregate, considering levels of 30% and 50% by mass. The SBAS used in this experimental programme had a predominantly crystalline structure of SiO2a-quartz, as determined by X-ray diffractometry in other studies, which revealed the absence of an amorphous halo in the diffractograms. The values obtained by chemical analysis (before and after standardisation) are presented in Table.

PRODUCTION OF MORTAR

Three series of mortars with different SBAS contents were produced, with 0% (reference mortar, RM), 30% (M30) and 50% (M50) substitutions of natural sand (by mass). The proportions of materials used in each series of mortar were the same proportions as determined by other studies [14], considering a mortar content of 51.3%.

PHYSICAL AND MECHANICAL CHARACTERISTICS OF THE MORTARS

The physical properties of the mortars were verified by testing their water absorption, void ratio and dry bulk density.

CARBONATION TEST IN MORTARS

Carbonation tests in the mortars were conducted in two stages: pre-conditioning and conditioning in accelerated environment.

1. Pre-conditioning The first step was initiated after 28 days of moist curing. The specimens were dried at 50 ± 5 C for 7 days to obtain mass constancy. Subsequently, the samples were kept for 5 days in a dry climatic chamber at a temperature of 23 ± 1 C and relative humidity of 60% ± 5%.

In the second phase (conditioning), the specimens were kept in an accelerated carbonation chamber. In this chamber, the CO2 content was 15% ± 2% (by volume) and the relative humidity ranged from 50% to 85%; both were chosen according to other studies. Some authors recommended carbon dioxide levels below 20%, in order to avoid microstructural changes developed at higher levels that are not developed under natural conditions

The use of mortar specimens was intended to exclude the interference of coarse aggregate in the analysis of concrete carbonation. Coarse aggregate acts as a barrier to the penetration of CO2 into the mortar matrix. Thus, the carbonation depth in concrete is usually less than the carbonation depth observed in mortars.

CHLORIDE PENETRATION IN MORTARS

The chloride penetration test was conducted using the colorimetry method by sprinkling silver nitrate and fluorescein solution.