Properties of sandcrete blocks stabilized with cashew apple ash as a partial replacement for cement.

The use of by-products from agricultural production as stabilizers in concrete and mortar in developing countries could result in numerous benefits. These by-products are readily available, cheap, and have a lesser carbon footprint. As Portland cement prices keep rising, the search for alternatives to sustainable construction materials is necessary. Cashew apples are left on cashew farms as waste material after the nuts have been removed due to lack of utilization. In this study, the properties of sandcrete blocks produced with cashew apple ash (CAA) as a partial replacement for cement were investigated. A total of 180 block specimens of size 100 × 100 × 130 mm were prepared from six different mortar mixes of control, 5, 10, 15, 20, and 25% CAA replacement of cement by weight were prepared. Results revealed that the highest compressive and tensile strengths after 28 days of curing CAA blocks were 11.45 and 1.08 N/mm2 respectively. The best water absorption resistance obtained was 2.66%. The study recommends the use of 5% CAA replacement of cement to block manufacturers for use in manufacturing sandcrete blocks. This study is useful because the cashew apple waste ash used as an alternative material to cement in sandcrete block production will be beneficial to the environment and may also save the cost of production of sandcrete blocks.

Paperbricks produced from wastes: modeling and optimization of compressive strength by response surface approach.

The high cost of building materials occasioned by the increased cost of constituent materials has contributed immensely to the problem of housing deficit faced in Africa and major developing countries of the world. Waste paper can be recycled into bricks but there are limited studies to that effect. Waste glass is used as partial cement replacement to reduce the cost of cement and is also used as a pozzolan. This study focused on the development of paperbricks from the wastes of paper and glass. Response surface method (RSM) was involved in the design of the experiment involving 4 factors: glass powder replacement of cement (A), curing duration (B), compaction pressure (C), and water/cement ratio (D). Box-Behnken method was engaged for the 4-factor, 3-level design. The result of ANOVA showed that experimental inputs had a significant effect on compressive strength response. Factors A, B, and C had a synergetic effect on the response while factor D had an antagonistic effect on the response. Combined interaction between the factors that the response depended on the interactive patterns of the factors. A statistical fit model was developed to predict the compressive strength of the composite. RSM optimization revealed a combination of 36.68%, 57.82 days, 8.50 MPa, and 0.364 for factors A, B, C, and D, respectively, predicting a strength value of 7.358 MPa. Validation experiment carried out using the optimal conditions yielded 7.54 MPa; a deviation of + 0.0247. Since the deviation is less than ± 0.05, the model was statistically validated and fit.

Mechanical performance and Taguchi optimization of kenaf fiber/cement-paperboard composite for interior application.

Demand for particleboards keeps increasing and as such more trees are fell for its production, engendering deforestation. For the purpose of reducing falling of trees, this study, focused on recycling of waste paper in the development of paperboard as alternative to particleboards used for furniture and interior household applications. Kenaf fiber (KF) was blended at varying proportions of 0, 1, 2, 3, 4, and 5 wt.% with 20 wt.% constant cement and 20 wt.% constant coconut shell powder while the remaining was paper pulp. Board specimen developed were cured for 14, 28, and 90 days and mechanical properties were examined. Results obtained showed that fiber dosage improved bond strength and screw holding strengths as compared with the control mix. Similarly, modulus of rupture was enhanced with KF loading as compared with control mix while 1 to 3 wt.% KF spawned enhancement of modulus of elasticity. However, 4 and 5 wt.% KF led to a reduction in the modulus. Infusion of the fiber enhanced tensile strength from 1 to 3 wt.% content. 14-day and 28-day curing periods were observed to improve properties while the 90-day curing period is detrimental to all properties. Optimization via signal-to-noise ratio revealed an optimum mix of 2 wt.% obtained for fiber and an optimum curing duration of 28 days.

Recycling of synthetic waste wig fiber in the production of cement-adobe for building envelope: physio-hydric properties.

Waste wigs are often disposed off in their volume on landfills, thus constituting a nuisance to the environment. Recycling these wigs in masonry bricks is a way via which they can be recycled and reused. On such premise, waste wig fiber (WWF) was recycled by incorporating into the cement-sand-clay composite mix for masonry bricks production. The challenges masonry bricks face include shrinkage and water susceptibility; hence, the contributory effect of WWF on physio-hydric properties was assessed in this study. Sample preparation entailed blending of cement, sand, clay soil, and waste wig fiber. The control mix was prepared by commixing clay with 10% cement (by clay volume) and 20% sand (by clay volume). Other mix proportions were reinforced with 1, 2, 3, 4, and 5% WWF by clay volume. Prepared composite brick samples were cured for 28 and 56 days and tested for physio-hydric properties. Results revealed WWF contributed significantly in improving hydro-resisting properties by minimizing porosity, water and moisture absorption, capillary suction, and water permeability. Furthermore, WWF contributed to dimensional stability by reducing shrinkages and weight loss. Hydration time impacts significantly in reducing apparent porosity, water permeability coefficient, moisture and water absorption, and capillary suction coefficient and increasing apparent density, weight loss, linear, and volumetric shrinkage. The general outcome depicts that WWF showed promising performance in bricks developed in enhancing water and moisture susceptibility resistance and promoting mass and dimensional stability, hence can be employed in reinforcing cement adobe bricks at an optimum mix of 5% vol fraction.