Editing Building material (section)

===Cement composites===
[[Cement]] bonded composites are made of hydrated cement paste that binds wood, particles, or fibers to make pre-cast building components. Various fiberous materials, including [[paper]], [[fiberglass]], and [[carbon-fiber]] have been used as binders.

Wood and natural fibers are composed of various soluble organic compounds like [[carbohydrate]]s, [[glycoside]]s and phenolics. These compounds are known to retard cement setting. Therefore, before using a wood in making cement bonded composites, its compatibility with cement is assessed.

Wood-cement compatibility is the ratio of a parameter related to the property of a wood-cement composite to that of a neat cement paste. The compatibility is often expressed as a percentage value. To determine wood-cement compatibility, methods based on different properties are used, such as, hydration characteristics, strength, interfacial bond and morphology. Various methods are used by researchers such as the measurement of hydration characteristics of a cement-aggregate mix;<ref>{{cite journal |last1=Sandermann |first1=Wilhelm |last2=Kohler |first2=Roland |title=Über eine kurze Eignungsprüfung von Hölzern für zementgebundene Werkstoffe - Studien über mineralgebundene Holzwerkstoffe, VI. Mitteilung |journal=Holzforschung |date=January 1964 |volume=18 |issue=1–2 |pages=53–59 |doi=10.1515/hfsg.1964.18.1-2.53 }}</ref><ref>{{cite journal |last1=Weatherwax |first1=R C |last2=Tarkow |first2=H |date=1964 |title=Effect of Wood on Setting of Portland Cement |journal=Forest Products Journal |volume=14 |pages=567–568 }}</ref><ref>{{cite journal |last1=Hachmi |first1=M. |last2=Moslemi |first2=A. A. |last3=Campbell |first3=A. G. |title=A new technique to classify the compatibility of wood with cement |journal=Wood Science and Technology |date=October 1990 |volume=24 |issue=4 |pages=345–354 |doi=10.1007/BF00227055 }}</ref> the comparison of the mechanical properties of cement-aggregate mixes<ref>{{cite journal |id={{INIST|8084764}} |last1=Lee |first1=A. W. C |last2=Hong |first2=Zhongli |title=Compressive strength of cylindrical samples as an indicator of wood-cement compatibility |journal=Forest Products Journal |date=1986 |volume=36 |issue=11–12 |pages=87–90 }}</ref><ref>{{cite journal |last1=Demirbaş |first1=A |last2=Aslan |first2=A |title=Effects of ground hazelnut shell, wood, and tea waste on the mechanical properties of cement22Communicated by A.K. Chatterjee |journal=Cement and Concrete Research |date=August 1998 |volume=28 |issue=8 |pages=1101–1104 |doi=10.1016/S0008-8846(98)00064-7 }}</ref> and the visual assessment of microstructural properties of the wood-cement mixes.<ref>{{cite journal |last1=Ahn |first1=W.Y. |last2=Moslemi |first2=A.A. |title=SEM examination of wood-Portland cement bonds |journal=Wood Science |volume=13 |issue=2 |pages=77–82 }}</ref> It has been found that the hydration test by measuring the change in hydration temperature with time is the most convenient method. Recently, Karade et al.<ref>{{cite journal |last1=Karade |first1=S. R. |last2=Irle |first2=M. |last3=Maher |first3=K. |title=Assessment of Wood-Cement Compatibility: A New Approach |journal=Holzforschung |date=30 October 2003 |volume=57 |issue=6 |pages=672–680 |doi=10.1515/HF.2003.101 }}</ref> have reviewed these methods of compatibility assessment and suggested a method based on the ‘maturity concept’ i.e. taking in consideration both time and temperature of cement hydration reaction. Recent work on aging of lignocellulosic materials in the cement paste showed hydrolysis of hemicelluloses and lignin<ref>{{cite journal |last1=Li |first1=Juan |last2=Kasal |first2=Bohumil |title=The immediate and short-term degradation of the wood surface in a cement environment measured by AFM |journal=Materials and Structures |date=September 2022 |volume=55 |issue=7 |doi=10.1617/s11527-022-01988-8 |doi-access=free }}</ref> that affects the interface between particles or fibers and concrete and causes degradation.<ref>{{cite journal |last1=Li |first1=Juan |last2=Kasal |first2=Bohumil |title=Degradation Mechanism of the Wood-Cell Wall Surface in a Cement Environment Measured by Atomic Force Microscopy |journal=Journal of Materials in Civil Engineering |date=July 2023 |volume=35 |issue=7 |doi=10.1061/JMCEE7.MTENG-14910 }}</ref>

Bricks were laid in [[lime mortar]] from the time of the Romans until supplanted by Portland cement [[mortar (masonry)|mortar]] in the early 20th century. [[Concrete masonry unit|Cement blocks]] also sometimes are filled with [[grout]] or covered with a [[parge coat]].