The pulp black liquor waste (PBL), a byproduct from paper-making, is applied as a cement admixture in two types of cement, namely Ordinary Portland cement (OPC) and Portland limestone cement (LPC). The results showed that the water of consistency of cement pastes premixed with PBL was gradually increased with the concentration of PBL while the setting times (initial and final) were decreased. So, it can be used as an accelerator. The compressive strength increased slightly during the early ages of hydration but sharply during the later ages, particularly with those premixed with PBL. The combined water content and bulk density displayed the same trend as the compressive strength, whilst the apparent porosity decreased at all curing times. The IR spectra of cement pastes showed that the intensities of the different peaks of cement pastes with PBL are higher than those of the pure samples. The SEM images proved that the incorporation of PBL with cement did not affect the chemical composition of OPC or LPC hydrates, but it only affected the physical state, shape, size, morphology and crystallinity of the formed hydrates. The 2 wt. % of PBL is the optimum concentration.
The present work introduces mild-room temperature-potassium permanganate treatment of cellulosic materials, namely already bleached pulps. Such treatment represents a new approach for upgrading pulp and paper quality, which is lacking in the literature. Potassium permanganate was investigated as a purifying and mild oxidizing agent for commercial already bleached softwood and bagasse pulps. It was found that treatment of the bleached beaten pulps, with 0.25-2% KMnO 4 (based on pulp weight), led to significant improvement in paper properties. The breaking length increased greatly and the brightness increased significantly due to treatment. The improvements were related to the degree of polymerization, and to the alphacellulose content of pulps. Moreover, potassium permanganate serves as a disinfectant and deodorizer. Thus treatment of bleached pulps with KMnO 4 is a promising remedy for the side effects which pulps suffer, during transportation and storage, before papermaking. p 3 of 18 tp
In this study, the use of bagasse fiber (BF) and unbleached bagasse pulp (BP) in a cement matrix, as a raw material, to produce lightweight construction materials is reported. The bagasse was used as partial replacement of cement at different levels: 0% (control cement), 1%, 2% 3%, and 4% by weight. The average size of bagasse fibers was less than 2 mm. Although a reduction in the physical and mechanical strength was observed, the incorporation of either fiber or pulp increased the water of consistency and setting time. A composite containing 4% of bagasse fibers can be used for lightweight concrete. FT-IR spectra showed that the BF or BP adversely affect the rate of calcium silicate hydrate (CSH) formation by decreasing its promotion.
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